MasterClass in Science Education: Transforming Teaching and Learning 9781474289429, 9781474289412, 9781474289450, 9781474289436

Table of contents :
Cover
Contents
List of Figures
List of Tables
Preface
Series Editor’s Foreword
PART I INTRODUCTION
1 Enquiring into Science Teaching
PART II PERSPECTIVES ON SCIENCE TEACHING
2 Critiquing the Science Curriculum
3 Reflecting the Nature of Scientific Knowledge in Science Education
4 Subject Knowledge and Continuing Professional Development
5 Identifying and Sequencing Learning Quanta
6 The Nature of Students’ Scientific Knowledge
7 Recognising Productive Lesson Activities
8 Seeking Evidence of Significant Learning
PART III ISSUES IN TEACHING SCIENCE SUBJECTS
9 A Twenty-First Century Notion of Scientific Knowledge
10 The Value of Not Believing in Science
11 A Challenge in Teaching Biology: Natural Selection
12 A Challenge in Teaching Chemistry: Submicroscopic Particle Models
13 A Challenge in Teaching Physics: Electrical Circuits in the Lower Secondary School
14 Teaching Science as Enquiry and Supporting ‘Minds-on’ Practical Work
15 Challenging the Gifted Young Scientist (and Other Young Scientists)
References
Index

Citation preview

MasterClass in Science Education

Also available in the MasterClass series MasterClass in English Education, edited by Sue Brindley and Bethan Marshall MasterClass in Drama Education, Michael Anderson MasterClass in History Education, edited by Christine Counsell, Katharine Burn and Arthur Chapman MasterClass in Music Education, edited by John Finney and Felicity Laurence MasterClass in Religious Education, Liam Gearon MasterClass in Mathematics Education, edited by Paul Andrews and Tim Rowland

MasterClass in Science Education Transforming Teaching and Learning Keith S. Taber

BLOOMSBURY ACADEMIC Bloomsbury Publishing Plc 50 Bedford Square, London, WC1B 3DP, UK 1385 Broadway, New York, NY 10018, USA BLOOMSBURY, BLOOMSBURY ACADEMIC and the Diana logo are trademarks of Bloomsbury Publishing Plc First published in Great Britain 2019 Copyright © Keith S. Taber, 2019 Keith S. Taber has asserted his right under the Copyright, Designs and Patents Act 1988 to be identified as author of this work. Cover design by 3C Design Partnership Ltd Cover image © Claudio Ventrella / iStock All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage or retrieval system, without prior permission in writing from the publisher. Bloomsbury Publishing Plc does not have any control over, or responsibility for, any third-party websites referred to in this book. All internet addresses given in this book were correct at the time of going to press. The author and publisher regret any inconvenience caused if addresses have changed or sites have ceased to exist, but can accept no responsibility for any such changes. A catalogue record for this book is available from the British Library. A catalog record for this book is available from the Library of Congress. ISBN: HB: 978-1-4742-8942-9 PB: 978-1-4742-8941-2 ePDF: 978-1-4742-8943-6 eBook: 978-1-4742-8944-3 Series: MasterClass Typeset by Integra Software Services Pvt. Ltd. To find out more about our authors and books visit www.bloomsbury.com and sign up for our newsletters.

Dedicated to the memory of my beloved wife, Philippa.

Contents List of Figures ix List of Tables xi Prefacexii Series Editor’s Foreword xiii PART I  INTRODUCTION

1 Enquiring into Science Teaching

3

PART II  PERSPECTIVES ON SCIENCE TEACHING

2 Critiquing the Science Curriculum 3 Reflecting the Nature of Scientific Knowledge in Science

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4 Subject Knowledge and Continuing Professional Development 5 Identifying and Sequencing Learning Quanta 6 The Nature of Students’ Scientific Knowledge 7 Recognising Productive Lesson Activities 8 Seeking Evidence of Significant Learning

69 79 95 107 121

PART III  ISSUES IN TEACHING SCIENCE SUBJECTS

9 A Twenty-First Century Notion of Scientific Knowledge 10 The Value of Not Believing in Science 11 A Challenge in Teaching Biology: Natural Selection

135 147 163

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Contents

12 A Challenge in Teaching Chemistry: Submicroscopic Particle Models

13 A Challenge in Teaching Physics: Electrical Circuits in the Lower Secondary School

14 Teaching Science as Enquiry and Supporting ‘Minds-on’ Practical Work

15 Challenging the Gifted Young Scientist (and Other Young Scientists)

175 191 203 213

References222 Index229

List of Figures 1.1 Two ways of conceptualising nested identities – as a category of scientist or as a category of teacher 4 1.2 A way of conceptualising science teacher identity as both scientist and teacher 4 1.3 Schematic suggesting that even when science degrees are mostly linked to school curriculum topics, they may offer limited coverage of the school science curriculum 5 1.4 Representation of a naive notion of the task of the teacher 8 1.5 A representation of a more realistic notion of the task of the teacher 8 1.6 Science requires coordination between theory and practical knowledge (represented here with the distinctions labelled by Aristotle) 11 2.1 Science education seen as a means to provide a background to (and pathways towards) vocational and professional preparation for a minority of students 28 2.2 Aristotle identified different forms of knowledge related to theory, craft know-how and wisdom in applying ethics in practice 33 3.1 Sailing the good ship science towards new knowledge 53 3.2 Conventions used in representations may not be so obvious to the uninitiated60 4.1 Researching or evaluating teaching requires us to define exactly what we think teaching actually is 72 4.2 Pedagogic content knowledge (PCK) is developed over time when teaching is treated as an enquiry activity 77 5.1 It may be helpful to literally ‘map out’ the relationship between key ideas in a topic, as in this concept map of some of the key ideas in this chapter 87 6.1 An individual will hold a vast range of different conceptions, with widely varying properties 98 6.2 What is learnt is not always what we thought we taught 100 6.3 Teaching analogies, models and metaphors used to relate abstract ideas to the familiar can sometimes act as impediments to further learning 102 7.1 Much of the work of the teacher is subject to external constraints, or involves real-time honing according to the responses of our students, so the lesson plan is the key focus for a teacher’s creativity and professional expression108

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List of Figures 7.2 Spot the couples: Applying the definition as a learning activity 7.3 What do we discover by calculating the turning effects of these pairs of forces? 7.4 An introductory task to review prerequisite learning (for the activity illustrated in Figure 7.3) 7.5 Some options for scaffolding the learning activity presented in Figure 7.3 8.1 There is a general tendency that those things that are easier to assess objectively relate to lower-level educational objectives 8.2 A hypothetical lesson structure, where the teacher shifts between exploring different ideas and developing the canonical scientific account, and between working with the whole class and supporting working in groups. (Based on the ideas of Mortimer & Scott, 2003.) 10.1 How the scientific approach of methodological naturalism relates to some key metaphysical positions 12.1 Students commonly misconstrue key features of the particle model of matter as taught in school 12.2 Perceived phenomena may be conceptualised both in formal macroscopic scientific descriptions and in theoretical models at a submicroscopic scale (after Taber, 2013e) 12.3 Chemists can use the symbolic level to bridge between a technical macroscopic description and a molecular-level explanation (after Taber, 2017) 13.1 A visual representation of average measured knowledge gains in classes taking an innovative module compared with a matched sample of classes being taught the same topic (electricity) according to their schools’ usual schemes 13.2 The overall design of the epiSTEMe module 14.1 Degrees of demand in working towards authentic enquiry 15.1 Learners need to be challenged by work with higher-level demands 15.2 Significant learning is most likely when activities are pitched to be challenging for a learner, but temporary support is provided to facilitate success

117 117 118 119 122

124 157 181

188 189

199 200 206 216 217

List of Tables 1.1 Some choices facing teachers 1.2 Some examples of resources on science education research 1.3 Comparing two search engines: the same search terms were entered into the Google search engine and the more specialist Google Scholar search engine to see how many resources were identified and the nature of the first ‘hit’ 7.1 Observing and analysing teaching 9.1 Measurements of the temperature of some water being heated 9.2 Measurements of the length of a spring under increasing loads 11.1 Two approaches to teaching evolution 14.1 Three of the categories used to survey student performance in science in England, Wales and Northern Ireland prior to the adoption of a national curriculum

11 14

17 109 141 141 173

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Preface Teaching is a challenging occupation, which can be frustrating at times, yet also intensely rewarding. This book is intended for all those teaching as specialists in the sciences, and invites readers to consider some of the key issues underpinning effective teaching. The book describes science as a kind of dialectic that depends upon the interplay between empirical observation and theory development. Much the same can be said about teaching. Teaching– learning is a complex process, embedded in myriad particular, unique, classroom contexts. Theory suggests a great many factors that can influence classroom learning, such that the possibility of identifying the relevant variables, let alone measuring or seeking to control them all, is unrealistic. However, teachers informed by theory can – through classroom enquiry – find out what is most important, and what can make substantial differences, in their particular professional contexts, and develop their practice to transform teaching and learning. That is, good teaching, just like science itself, is a form of ongoing enquiry. Teaching-as-enquiry is seldom as straightforward as the naive stereotype of how science is sometimes considered to proceed through a clean sequence of conjectures and critical experiments – rather it often proceeds through hunches, compromised innovations and qualitative evaluations lacking meaningful control conditions. Yet scholarship into the nature of science suggests that, even in the natural sciences, progress seldom matches the simplistic ideal of hypothesis–test–knowledge. Rather, science in the making involves extended periods of compromised investigations relying on tacit decision-making, and offering multiple theoryladen interpretations. The teacher who sees their teaching as a form of enquiry is involved in scientific work to the degree they adopt the scientific attitude; that is, to retain a critical perspective on their own views, and to see the knowledge they develop in their classroom work – although certainly a basis for professional decision-making – as open to refinement, or even substitution, in the light of future classroom experience. In this way, the scientist who chooses to enter teaching brings not only their scientific knowledge but also scientific practice to their classroom work.

Series Editor’s Foreword It is rare to find a text which is both informative and engaging, and with such a strong but balanced personal voice as this – Professor Keith Taber’s MasterClass in Science Education – and it is a delight to read. Known widely for his work within science but also teacher education and teacher research, Keith Taber brings a challenging but informed sense of debate to the field of science education and invites his readers in to take up that conversation with enthusiasm. Science in a school context is generally understood as three subjects – physics, biology and chemistry – so it is completely appropriate to start in Part I with an investigation into how science teachers construct knowledge. This is a theme which continues throughout the book, and within the context of both research and practice, teachers are positioned as representing knowledge seekers – bringing both scientific understanding but also scientific perspectives to the whole question of learning. This first chapter establishes the parameters and types of questions that shape the book. Part II – ‘Perspectives on Science Teaching’ – critiques some of the thinking around the construction of (and need for) the teaching of science, but with a clearly practical approach. So in this part, there are discussions about professional development, organisation of the curriculum, planning for effective teaching and learning, and how to assess that learning, mirroring always the scientific principles and practices that distinguish knowledge building in science. Part III returns us to the question of knowledge – how knowledge is understood and how it changes. Chapter 10 asks perhaps the biggest question of all – what is the relationship between science and religion? This is an area that Professor Taber has researched in widely, and his presentation (with reference to naughty fairies and lost socks) is typically entertaining and deals with the entirely serious in ways which make this fascinating area simultaneously accessible and profound. It is a chapter which in my view should be required reading for all science teachers. Chapters 11–13 address separately the three key science disciplines, and Chapter 14 returns us to enquiry and research as the basis for meaningful teaching and learning. As Keith Taber says in the Preface, good teaching, just like science itself, is a form of ongoing enquiry. Students are here positioned not as passive receivers of a body of knowledge, but as creators of knowledge through engagement with real events – ‘An alternative is to start by asking students to undertake practical activities which produce phenomena they have not yet been taught about at the theoretical level. If they observe the natural phenomena for themselves, especially ones that might appear counter-intuitive, then there is a motivation to

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Series Editor’s Foreword develop an explanation, which involves the construction of some theory.’ This challenging of students as ‘real’ scientists provides the theme of the final chapter, where Keith Taber outlines an approach to differentiated teaching which starts from the top, with the expectation that that is where students will either arrive or progress from – a refreshing antidote to the idea of teaching as arduous climbing up from foothills to peak. The book is thus a tour de force of science teaching and learning, modelling approaches through its own stance of enquiry and thoughtful engagement with the big questions of science and science teaching. It is a privilege to have Professor Taber’s book as one of the MasterClass series. I’d like to end on a more personal note. You may have seen Professor Taber’s dedication of this volume to the memory of his wife, Philippa. Keith and Philippa shared an approach to the world characterised by warmth and humanity, of kindness and good humour. Philippa Taber suffered a period of ill health with stoicism, rarely allowing it to dominate her landscape and instead focusing on the outside world and all its opportunities. Her untimely and indeed unexpected death was a shock to everyone who knew her, and she is missed. I am honoured that Keith chose this book for his poignant dedication. Dr Sue Brindley, University of Cambridge

Part I Introduction

Enquiring into Science Teaching

Chapter outline Teaching science, or teaching a science? Every teacher of science is a learner of science Every teacher of a science is a science teacher The teacher as an evidence-based practitioner Developing as a leader in science teaching Suggested further reading

3 6 9 10 18 21

This book in the MasterClass series is designed to support teachers of school science subjects who wish to develop their professional skills and standards. This introductory chapter introduces the approach taken in the book and the philosophy informing that approach – the notion of the ‘fully professional science teacher’. First though, I briefly explore a potential tension that may be felt in science teaching between being a teacher of ‘science’ and a teacher of ‘a science’ subject.

Teaching science, or teaching a science? In preparing this book, I have assumed that the readership will in broad terms be science teachers (or those preparing to be science teachers). However, it is recognised that for some readers there may be a tension between being a ‘science teacher’ and being, for example, a biology teacher. Other teachers may not recognise this tension, either considering themselves to simply be a ‘science teacher’ or accepting they can be both a science teacher and a biology teacher (or chemistry teacher, or physics teacher etc.) without this being problematic in any way.

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MasterClass in Science Education More broadly, some secondary teachers (like many primary teachers) see themselves as a teacher first, and see the subject(s) they happen to teach as less critical to their professional identity. There is the story of the conversation at a dinner party which included the following exchange: ‘I understand you are a teacher – what do you teach?’ ‘Children.’ Yet many science teachers consider themselves primarily as scientists who have entered teaching and may even think of themselves as having more in common professionally with other (non-teaching) scientists than teachers of other subjects (see Figure 1.1). Identity may be complex and nuanced, and there is nothing wrong with being, say, ‘a teacher’, ‘a secondary teacher’, ‘a chemist’, ‘a scientist’, ‘a science teacher’ and ‘a chemistry teacher’ – with these different emphases coming into focus at different moments. So the reader may be a teacher of secondary-age children, and of science and of (say) physics, without any contradiction (see Figure 1.2).

Figure 1.1  Two ways of conceptualising nested identities – as a category of scientist or as a category of teacher.

Figure 1.2  A way of conceptualising science teacher identity as both scientist and teacher.

Enquiring into Science Teaching Some readers will be largely teaching within a science specialism, and perhaps in some school contexts mainly working with students at the high-grade levels of the school system. Others will teach an undifferentiated curriculum subject that is labelled as ‘science’. Many others will shift between subject labels within their timetable according to the particular group they are teaching at a particular moment. Teachers will also differ considerably in terms of both the extent to which they feel their preparation for teaching was focused within a specific science subject and in the extent to which they feel their own academic background supports teaching across the wider science curriculum. In the English system (where the author of this volume has worked in schools, further education and initial teacher education), teaching candidates may enter graduate training courses for science teaching with a wide range of degree backgrounds such as geology, genetics, astrophysics, psychology, industrial chemistry and electrical engineering. A candidate should hold a degree where at least half the material studied is relevant to the school curriculum subject. This was easily met by such a range of graduates from different science disciplines – but, of course, having a degree which is mostly relevant to what is taught in school science is not the same as having a degree which is relevant to most of what is taught in school science (see Figure 1.3). There is generally an issue then that teachers’ own subject knowledge, even when very advanced, is unlikely to be a perfect match for the range of topics they may be expected to teach. That is often true even if someone is only teaching (or intending to teach) biology or chemistry or physics. The graduate in marine biology or biochemistry or chemical engineering or astrophysics will find their degree-level preparation does not cover all of the topics taught within a school science subject. In some other national contexts, it is commoner for teachers to focus on one teaching subject (chemistry, say) and to enter undergraduate degree courses designed to prepare them

Figure 1.3  Schematic suggesting that even when science degrees are mostly linked to school curriculum topics, they may offer limited coverage of the school science curriculum.

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MasterClass in Science Education for teaching just that particular specialism. There can be a much greater fit between degreelevel education and later teaching practice in such a system. However, sciences do not remain static: so even in this situation the teacher will find new curriculum topics introduced which they may feel are outside their area of expertise. I recall changes in teaching schemes during my own time teaching in schools that introduced some topics which I had never studied during my own school or university education. I was also asked to teach courses with content outside my own background. For example, on moving to a new school where I was to teach physics and chemistry, I was asked if I could take on the ‘physical environment’ section of an environmental science course that some senior students in the school chose as one of their (A level) options. I was receptive to the idea, and it was sold to me on the basis that this part of the syllabus was really chemistry and physics. It transpired that although the material I was to teach was underpinned by physics and chemistry, it included a lot of earth science I had never studied myself. As a teacher there are three attitudes one can take in responding to such challenges: 1. I am a specialist, with specialist knowledge, and that is what I teach. 2. The school knows what my background is, and if they timetable me to teach anything else, it is their responsibility to prepare me properly for teaching new subject matter. 3. I am a scientist, and a qualified teacher, and I should be able to develop both subject knowledge (what I need to teach) and specialist pedagogic knowledge (how to effectively teach particular subject matter) from within any area of science.

Only the last approach seems appropriate for a professional science teacher. That is not to say that schools should ignore teacher specialisms (or indeed preferences) and assign teaching without negotiation in order to fill gaps in timetabling. Yet as teachers we should value learning and personal development: none of us would be very impressed with students in our classes who claimed they enjoyed learning about acids (or plants or magnetism) but had no intention of making any effort to learn about rates of reaction (or food webs or optics) as that was not something they were interested in – not ‘their topic’.

Every teacher of science is a learner of science An assumption underpinning this book then is that although science teachers, or teachers of specific science subjects, should be well prepared in terms of subject knowledge, it can never be assumed that just because someone is a graduate or a qualified science teacher they know enough science to support all the curriculum topics they will be expected to teach. Becoming a ‘master’ teacher will involve continuing to learn science throughout a teaching career – whether this means topics outside a specialist background, completely new areas of science or the latest applications and theoretical developments in areas of strength.

Enquiring into Science Teaching Without wishing to unduly alarm or insult readers, I would also suggest that readers of this book will also have got some of the science they think they understand wrong. Perhaps there are some exceptions among the discerning readers selecting to pick up this volume … but I actually suspect not. That (perhaps seemingly arrogant or condescending) claim is based on both personal experience and a wealth of research in science education. As a teacher in schools and further education I found even the most committed and capable students sometimes misunderstood concepts they were being taught. I also sometimes found some of my teaching colleagues got things wrong – including things they had been confidently teaching for years. I am sure that I was no exception to this general rule – although of course it is easier to spot flaws in another’s knowledge than our own. I have interviewed graduates with excellent degree results from prestigious universities applying for teacher preparation who have demonstrated errors in their understanding of basic concepts – sometimes in topics they have specially prepared to present at interview. On one occasion I remember one candidate with a master’s degree telling a colleague on the interview panel that she, the applicant, was right and that the interviewer (a very experienced teacher and teacher educator, and a fellow of both a Cambridge college and the Institute of Physics) had got her physics wrong. The applicant misunderstood her physics, but was convinced that her incorrect understanding was the accepted science. Confidence is generally something positive in classroom teaching, but there is a balance to be reached between being confident in what we know and accepting that we cannot know everything about our subject, and that being human we can also be wrong sometimes. Talking to graduates on teacher preparation courses, or reading their work, or observing them teaching also reveals such problems. Teacher subject knowledge is generally flawed (see Chapter 4), that is, not perfect. When we think about why that could be, it becomes obvious this is almost inevitably going to be the case. Beyond personal experience, the research literature suggests that in just about any topic one might select, learners commonly demonstrate misunderstandings of science concepts (Taber, 2014). This is discussed further in Chapter 6. Given the nature of human learning, and the nature of scientific concepts, intended learning is something often achieved only with considerable effort by students, and great skill on the part of the teacher. Students generally come out of science learning having misinterpreted and misunderstood some (and in some cases, a good deal) of what they were expected to learn (Driver, 1983). That even applies to some extent to those who go on to teach the subject. Indeed it may be that in some especially tricky science topics, misunderstandings of teachers are being effectively taught to students, some of whom will go on to become teachers and teach the flawed ideas themselves (Taber & Tan, 2011). It is important not to be alarmist or overly pessimistic here. Of course, students do often develop strong knowledge in some topics. However, this issue of flawed subject knowledge is one key theme of this book because common sense might suggest to us that when students are taught topics, they will learn what they are taught to some extent. That is, the expected likely outcome of studying will be a point somewhere on a dimension between ignorance of

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MasterClass in Science Education the topic (knowing nothing) and correctly learning all the material (see Figure 1.4). Perhaps we might conclude from an assessment a student has learnt 65 per cent of the topic material and still has to learn 35 per cent. Yet that common-sense view is not reflected in practice. Student knowledge is not just either (somewhat) present or (largely) absent – but is very often somewhat different to what is being taught (see Figure 1.5). Ignorance, what might be considered as a gap in expected knowledge, is relatively easy to identify and respond to. Knowledge that only partially matches the canonical account, and which can differ from it in a wide range of ways, and to various degrees, is a much greater challenge for the teacher – in terms both of ‘diagnosis’ and ‘treatment’. The same problem exists, even if to a much lesser extent, regarding the imperfections in teacher knowledge, which are often likely to be more extensive when one is teaching outside a main science specialism.

Figure 1.4  Representation of a naive notion of the task of the teacher.

Figure 1.5  A representation of a more realistic notion of the task of the teacher.

Enquiring into Science Teaching

Every teacher of a science is a science teacher This book is then addressed to teachers of science, including teachers who primarily identify with particular science subjects. Every science topic has its own challenges for teachers: particular challenges that are specific to that topic. Later chapters give some examples of this. Chapters 11–13 highlight rather different challenges relating to three particular school science topics, whilst raising issues that will be met by all science teachers. Moreover, there are particular issues that tend to occur across topics within the particular science subjects. An example might be the application of mathematics. This can be an issue in all sciences, but may be a particular problem for some students in physics, as in the higher grades most topics involve what appears to many students a considerable use of mathematics. In practice this often involves little more than arithmetic and some basic algebra – a rather limited set of mathematics competences. However, for students struggling to apply this level of mathematics this still constitutes a barrier to performing in most physics lessons. In chemistry, most topics require students to coordinate thinking about chemical concepts at the level of substances handled in the laboratory with thinking in terms of models of matter at submicroscopic scales (e.g. molecules, ions). This is challenging for many students (an issue explored in Chapter 12), and again is an issue that recurs throughout a chemistry course. Beyond the specifics of particular science topics there is the wider question of what it means to teach or learn science/a science. This has become increasingly important in recent years as national standards and curricula, and so examination specifications and high-stakes assessment, have increasingly focused on issues such as scientific literacy and understanding the nature of science (Hodson, 2014; Lederman & Lederman, 2012; Roberts & Bybee, 2014). (This will be discussed further in Chapter 2 and revisited later in the book.) School science education should be about not just teaching some science, but also teaching about science itself, and it should empower students to engage with science in the public domain in ways that will support them as economic and political agents – that is, as citizens who will make choices in how to spend their money, and whether to support particular interest groups (such as environmental pressure groups, animal welfare organisations), potentially campaigning on issues that concern them (which might include nuclear power, fracking, abortion, genetically modified crops or intensive agriculture) and voting in elections for particular political candidates. School science should support learners in developing the critical thinking and background knowledge needed to address myriad science-related questions they might face, such as: Should they spend extra money on the motor oil with ‘muscle molecule’ or the shampoo with added protein? zzShould they opt for elective surgery, or invest in homeopathic remedies? zzShould they campaign against the proposed wind farm planned near a local beauty spot? zz

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MasterClass in Science Education Whilst some basic science might make people generally more sceptical of pseudoscience in advertising, these are not mostly issues where science can offer a definitive answer (as judgement also requires the application of personal values). Yet both some scientific knowledge and an understanding of key issues in the nature of science (such as the nature of evidence, what makes knowledge claims robust and trustworthy) may be essential in reaching an informed view. Teaching science, or a science, is then more than teaching something of the established products of the science that has already been completed (the structure of the kidney, the ideal gas equation, how to test for chloride ions in solution), but also means inducting students into the practices that make for scientific thinking and working.

The teacher as an evidence-based practitioner Science is evidence based. Evidence is also always a matter of interpretation, so data become evidence in a particular theoretical context. Therefore, as scientists, we should always be sceptical of the ‘self-evident’, as things become self-evident only within a particular mindset (or ‘paradigm’), and even in science there is sometimes a paradigm shift where well-established assumptions have to be put aside (Kuhn, 1996). However, theorising without seeking empirical evidence is not science, but perhaps philosophy. There is nothing wrong with philosophy qua philosophy, but the essence of natural science is an interplay between theory and evidence. Modern science developed from what was previously called ‘natural philosophy’ when the need to collect empirical evidence about natural phenomena was recognised as centrally important to understanding nature. The notion that there were different kinds of knowledge, including theoretical and practical know-how, dates back at least to Aristotle (see Figure 1.6), and science requires drawing upon both of these domains. Teaching should also be an evidence-based activity. This is clear if we consider some alternative strategies that teachers could use (see Table 1.1). Many more similar examples could be offered, but I suspect it is clear that evidence-based practice is the more professional approach. The type of evidence collection involved here would not usually be termed as research, but is in keeping with a scientific approach to teaching that checks assumptions against evidence.

Research-based practice The examples in Table 1.1 make it clear that collecting classroom evidence is a sensible approach to inform teaching. The fully professional science teacher is equipped not only to teach science but also to identify and investigate issues and problems arising in practice, and to seek and evaluate potential solutions (Taber, 2013a). So a good teacher is a researcher in the same sense that a good medical doctor is: some medics move into research as a specialised activity (as a small proportion of teachers do), but all doctors are expected to keep up with new

Enquiring into Science Teaching

Figure 1.6  Science requires coordination between theory and practical knowledge (represented here with the distinctions labelled by Aristotle).

Table 1.1  Some choices facing teachers a teacher can assume that students in the class have

or

a teacher can use diagnostic assessment to see whether

already learnt relevant concepts that should have been

students in the class have already learnt relevant concepts

taught in earlier classes

that should have been taught in earlier classes

a teacher can guess whether the learning objectives for a

or

topic have been achieved a teacher can decide that an explanation given to the

have been achieved or

class was clear, and was understood as intended a teacher can assume that completing practical work

a teacher can test whether the learning objectives for a topic

a teacher can check whether an explanation given to the class was clear, and was understood as intended

or

a teacher can investigate whether students in the class

ensures that students appreciate the ideas the practical

appreciated the ideas the practical activity is meant to

activity is meant to illustrate

illustrate

a teacher of a class of Christian students can deduce

or

a teacher of a class of Christian students can decide that

that because mainstream churches are happy to

even though mainstream churches are happy to accept

accept scientific ideas about origins (of the universe,

scientific ideas about origins (of the universe, of species),

of species), there is no reason students will be

it might be sensible to check whether any students

uncomfortable in studying these ideas in science

are uncomfortable in studying these ideas in science

classrooms

classrooms

a teacher may assume that no young people today would

or

a teacher can see if there is a need with some classes

consider professions such as engineer, physicist or

to actively challenge notions that professions such as

surgeon as less suitable careers for women

engineer, physicist or surgeon are less suitable careers for women

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MasterClass in Science Education research relevant to their work, and to be alert to issues that should be reported to the wider profession. Moreover, as everyone is slightly different, and responds to treatments differently (for example, the genetic differences that make us all somewhat unique also lead to a similar diversity in the behaviours of our individual immune systems), medical practice itself can be seen as a kind of case-based research programme. Whatever has happened in the past, this next patient might offer a new challenge. That should sound familiar to those of us working in education: whatever has happened in the past, this next student, this next group of learners, this next class or year group might offer a new challenge. Seeing teaching as in part being a kind of ‘learning doctor’ (Taber, 2014) helping different students overcome various barriers to effective learning means recognising good teaching as necessarily being a kind of research-based practice. We can never just pull out the ‘same’ lesson and teach it again with the assumption it will be optimised for the next class we meet. The observant teacher does not need to make a particular effort to go looking for research projects, as they will present themselves regularly.

Ethical enquiry into practice However, some readers of this book will be looking for a specific research focus or topic if they are taking a course (for a higher degree, for example) that requires them to undertake and report a study for a dissertation project. At various places in the book I have juxtaposed the main text with some ‘enquiry into practice’ ideas related to the topics being presented. These are purely meant as illustrations, and most readers will recognise many other possibilities related to the chapters in this book. Some of these examples include some hints at possible aspects of appropriate research methodology that might fit the suggested project. However, this book is not primarily about methodology, and readers setting out on a research course should refer to suitable sources. My own Classroom-Based Research And Evidence-Based Practice (Taber, 2013a) is an introduction to educational research written with teachers in particular in mind; however, that is only one of many relevant texts available. The suggestions for enquiry into practice are purely intended to offer examples of the kinds of enquiry activities that a teacher might find fruitful. Many of them are presented as a limited informal activity, but could be expanded into a more substantive project (perhaps as the basis of a research thesis, for example). It is assumed that in carrying out any of these activities, or any others, the teacher will consider carefully the potential for their actions to, for example, inconvenience, worry, disturb, disrupt or threaten others, and consider what information needs to be shared, and when an activity needs express consent from others who may be influenced. It is very important that teachers carrying out enquiry into their practice are mindful of the ethics of research. A number of the suggestions for enquiry into practice made in this book refer to activities such as observing and recording teaching. Clearly if you are observing another teacher, this should be done with their knowledge and approval. If you are

Enquiring into Science Teaching recording  your own class, it is sensible to explain to them (in general terms) that you are recording to allow you to review the lesson later. If such recording is undertaken purely for use within the school it probably will not require permission from parents, but you should check any school policies in place. If you are collecting data for publication (see below), it is likely you will need students’ and often parental approval. More detailed considerations of research ethics can be found in many books on education research (e.g. Chapter 9 in Taber, 2013a).

Ideology versus research Taking an evidence-based approach is in contrast to an ideological (and dogmatic) approach which does not consider that evidence is pertinent because the right way of doing things can be deduced simply by giving some thought to matters. Such a ‘principled’ approach might be termed a priori – but that could imply that such ideology somehow arises from pure reason rather that someone’s own (inevitably particular) experience. Teachers might be critical of such a stance when it is applied to public policy – such as when politicians seem to approach educational issues from an ideological perspective, and evidence may be sought, but to support or illustrate a preferred course of action. The scientific attitude requires that evidence is collected without prejudice and analysed and presented as fairly as possible. An ideological approach does not allow data to challenge existing understanding (which is simply assumed to be correct), but rather selects or suppresses data according to its value in supporting an argument. This is fine as rhetoric, but is not acceptable when we want to take a scientific (critical) approach. Of course, there is much research into the history of science which shows scientists do use rhetorical tools, and even sometimes select and suppress evidence to support views they think are right, but that reflects the imperfection of particular humans and the complexity of scientific arguments and evidence. The ideal is to reduce bias and be as open-minded and evidence-led as possible (see Chapters 9 and 10).

Determining the current state of knowledge Educational research outcomes often depend on context. What studies showed fifty years ago may not be the case now. What works with this class in that year group in this type of school with this teacher may not work so well in other contexts. This is a major complication for researchers. However, this does not mean that results of existing research will never apply to a new context, just that we should be careful not to assume they do. When a particular educational problem or issue is identified in some context, it is certainly sensible to ask whether the issue has already been studied. For example, I have probably never met the students in the classes taught by readers of this book. But there are a number of alternative conceptions in physics, chemistry and biology that I would expect some of the students in any class of secondary students are likely to exhibit when questioned about their ideas. Research has shown some alternative conceptions are very common regardless of diverse teaching contexts (see Chapter 6).

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MasterClass in Science Education If your department is concerned that the highest-achieving students in your school are not sufficiently challenged in science classes (see Chapter 15), then some of the various strategies and initiatives reported in the literature may prove to be helpful. These will likely not all be practical in your context, and some things that have been shown to be useful elsewhere may not have the desired effects in your context, but it still makes sense to look for starting points for your own evidence-based practice in what has proved to be helpful elsewhere. Education, as science, has an extensive research literature. There are many general educational journals, as well as many specialist journals (for example those focusing on science education). There are review journals that publish accounts of areas of research – for example the journal Studies in Science Education. There are many books reporting research, including some handbooks and other reference works that look to offer accounts of the state of the area of research (see the examples in Table 1.2). Accessing this research is not always so straightforward. Research journals are often very expensive and only available in research libraries such as those in universities. Academic books also tend to be expensive, and too specialised for most community (or school) libraries. Most journals are now available online (as well as, or even instead of, in hard copy), but often the subscriptions are still expensive. Table 1.2  Some examples of resources on science education research Type of resource

Resources

Review journal – offers accounts of areas of

Studies in Science Education

research Science education research journals

International Journal of Science Education Journal of Research in Science Teaching Research in Science Education Science Education

Research journals in specific science subjects

Chemistry Education Research and Practice Journal of Biological Education Physics Education

Periodicals aimed at teachers

School Science Review Education in Chemistry Science in School

Handbooks reporting areas of research

Second International Handbook of Science Education (2012 – Editors: B. Fraser, K. Tobin, & C.J. McRobbie) Handbook of Research on Science Education, Volume II (2014 – Editors: N.G. Lederman & S.K. Abell) International Handbook of Research in History, Philosophy and Science Teaching (2014 – Editor: M.R. Matthews)

Enquiring into Science Teaching Teachers who are registered as students in universities or similar organisations will likely have access to most of this material. Other teachers may find their local university offers some access to graduates or local teachers. Membership of a community library may allow access to some material by special arrangements (for example in the UK, libraries may buy vouchers for interlibrary loans through the British Library, which will provide loans of books or photocopies of journal articles). Teachers who have membership of some professional or scholarly organisations may find they have access to material through those organisations. For example, the Royal Society of Chemistry provides members with online access to material it has available (which includes some material on chemistry education, as well as a great deal of chemistry research).

Open access In recent years, there has been a shift in academic publishing which is making access to research both easier and yet more complicated. This is a combination of online publication and the open access movement. Online publication, making journal articles available via the internet, can lead to less expensive journals. A lot (but not all) of the cost of a traditional journal is derived from printing the journal and posting it around the world. Online journals have some production costs (editing, formatting, websites) but avoid the considerable expense of making hard copy. Whilst many traditional journals offer both options, in the last decade or so there has been an explosion of new internet-based journals on just about every conceivable subject. This makes finding apparently relevant research much easier – but at the cost of a decrease in quality of much published research – a point returned to below. The other innovation, open access, concerns a change in the business model for journals. There are basically four options for funding a journal: 1. 2. 3. 4.

charge those who want to read it; charge those who want to be published; persuade a sponsor (which might be philanthropic, or an advertiser) to provide support; some combination of the above.

The traditional model used by most journals was that the costs were largely recovered by charging readers for the journal. Authors were not usually charged for publishing their articles, and publication depended upon judgements of research quality made by editors supported by evaluations carried out by expert peer-reviewers. One objection to this model is that much research is funded directly or indirectly from the public purse – so in effect people’s taxes – so to ask people to pay to read the results means that they were paying twice. So government funding agencies are moving to a policy that research they support must be published as open access. A lot of top journals now operate a system where they charge readers who subscribe to the hard copy of the journal, and anyone can buy downloads of most of the published articles, but some are now freely available. If you go to the websites of research journals you may very well find that you can freely access some, but not all, of the articles in a particular issue. The articles that you can freely

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MasterClass in Science Education download may be selected by the publisher as a kind of taster of the journal, or those for which a publication fee has been paid by authors or their institutions to make work more accessible. Articles that are only initially downloadable upon payment of a fee may become open access once no longer recent (say after two years). Publishers may also allow authors to pass on free copies of the PDF version of their article if you contact them directly, even if you have not paid to download it. Authors may also be allowed to put manuscript copies of the articles (the version they prepared for submission, which may not be identical to the final published version and will not be in the final format) on their website, in institutional repositories or on community sites such as ResearchGate where researchers share their work. This is a somewhat messy and confused situation, so if you find a reference to an article in a top journal that looks useful, it is worth checking if it is freely accessible at the journal website. If it is not, you may still be able to get a free copy from the author’s webpages or by emailing the author and asking politely for a copy. There are now many journals where all the articles are free to access. This includes some high-quality journals. The top-ranked journal in chemistry education (Chemistry Education Research and Practice) is published by the Royal Society of Chemistry on its website and all articles are freely available as the society’s Education Division sponsors the journal. By contrast, many of the new internet-only, free-access journals do not have the same level of quality control as the more established journals. In some cases, this may simply be because new journals cannot attract experienced experts in the field to act as editors and reviewers, so the peer review process for the evaluation of articles is not always as robust as with the top journals (where academics get kudos for their work as editors or reviewers). However, many of the new journals seem to be motivated purely by financial considerations such that there is pressure to accept articles because of the associated author publication fees. Many well-established, top journals are published by commercial academic publishers, and these companies prize their reputation for publishing quality material and defer all editorial decisions to well-respected senior academics. Many of the new journals are not in a position to attract the same level of expertise or to be so choosy in what they publish. A good journal will reject most of the submissions received as of poor quality or of limited value to readers. However, if an author is prepared to pay the publication fee, they can almost certainly get a poorly conceived and reported study into a journal in the current market where there are so many new journals seeking material for publication. Top journals publish studies of high quality that are considered original and significant. Other reputable journals publish competent reports of less innovative research. Some of the newer internet journals seem desperate to attract any submissions (Taber, 2018a). This is problematic for those who may not be in a position to judge the quality of a journal – such as many teachers. (See Chapter 6 of Taber, 2013a for guidance on evaluating the quality of published research.) The journals listed in Table 1.2 are among those highly regarded and considered to have robust quality controls – and are good places to start looking for research that can inform classroom practice (and classroom research projects).

Enquiring into Science Teaching

The ‘paper chase’ One way to find relevant articles is to look at the contents pages of the top journals in a field. This will help you find some relevant papers, but it is inefficient. Most top journals have search facilities on their websites (but be careful to choose the ‘in this journal’ option, or you may be searching a database of hundreds of mostly unrelated journals) where you can enter keywords such as ‘differentiation’, ‘inquiry’, ‘genetics’ and ‘diagnostic assessment’. There are also specialist indices and search tools that work across a wide range of journals, but again these may require library access as these are often subscription services not available to the public. However, one very useful tool that is freely available is Google Scholar. Table 1.3 presents a comparison between the general-purpose search engine Google and the more specialist search engine Google Scholar for some searches related to science education. Google Scholar reports only articles in journals or similar academic sources. The general search engine will include results of this kind, but usually among a much wider range of material. The general search will include material relevant to teaching, but Google Scholar is better for a more directed search looking for formally published research (of the kind suitable for citing in academic assignments). Once relevant papers are found and accessed, some of the works cited in those articles may themselves be worth seeking out. Table 1.3  Comparing two search engines: the same search terms were entered into the Google search engine and the more specialist Google Scholar search engine to see how many resources were identified and the nature of the first ‘hit’ Google Search terms

“alternative

Hits

Top hit

Hits

c.43,000

Royal Society of Chemistry

c.9,340

c.55,100

A PowerPoint presentation

“physics”

from the Institute of

“electricity”

Physics to use in teaching c.613,000

Article in Evolution:

“biology”

Education and

“understanding”

Outreach

“enquiry teaching”

Review article in Studies in Science

resources

“chemistry”

“natural selection”

Top hit

Education

webpage with teaching

conceptions”

“teaching models”

Google Scholar

264

PDF version of a report

“simulations”

from the National

“laboratory”

Endowment for Science,

722

Article in International Journal of Science Education

c.866,000

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Article in Science Education

Article in Research in Science Education

Technology and the Arts “teaching science” “gifted learners”

c.79,900

Website of a university scholar

331

Article in Gifted Child Quarterly

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MasterClass in Science Education The research literature can suggest approaches to developing science teaching that have been proposed and tested in various contexts. Those contexts will match your own professional context to different degrees – but can suggest starting points for testing out ideas and approaches in your own classroom. Through such classroom enquiry, you can improve your own professional practice, as research-informed (that is, informed by being aware of what published research suggests) and evidence-based (that is, testing out, and evaluating, ideas in your own teaching) practice.

Developing as a leader in science teaching For many new teachers the idea of undertaking enquiry that might be published in any formal sense may seem unrealistic – although it is not unknown for trainee teachers to write up their work for journals, and at least one teacher training partnership has its own journal for this purpose (The Journal of Trainee Teacher Educational Research at http://jotter.educ.cam. ac.uk/). Your work as a science teacher may offer you enough challenges, or (more optimistically) enough satisfaction, for you not to be thinking about looking to take on responsibility for other colleagues and working towards a more senior role. I certainly felt that way when I started my first teaching job, and I even considered that I might stay in that school, doing that job, for the rest of my working life. However, by my third year, I was ready to take on some part-time study to further my knowledge and understanding of science teaching and learning, and soon after, a situation developed where I was asked to take on responsibility to lead on the teaching of physics in the school. When we think of leadership we might imagine this means the head teacher, and perhaps the heads of faculties or departments, but in the modern school leadership is understood in a more inclusive and distributed way. Responsibilities may be shared more widely so that most teachers in a department are given particular issues to focus on (different subjects, age groups or courses; the gifted; science clubs etc.). A fairly inexperienced member of a department might well be asked to take on some modest responsibility which offers them both a sense of sharing leadership and an opportunity to build up their record of contributions for when they might seek to apply for a more senior role. The effective departmental leader is not just reducing their own load by sharing out responsibilities, but is also capacity-building through delegation by supporting leadership development in less senior colleagues. One particular opportunity to share leadership is through research. A less senior member of a department with a strong interest in enquiry teaching, or differentiation, or multimedia production, or diagnostic assessment etc. can be charged with taking on a research project in this area and reporting back to the department. Leadership here comes not through seniority but through the authority of having done the reading, tested out ideas and activities, and evaluated the student response; that is, through having developed expertise to be shared with departmental colleagues.

Enquiring into Science Teaching

Putting your work in the public domain It might be asked whether there is a difference between evidence-based practice, as discussed above, and ‘actual’ research; does research go beyond the thoughtful approach to questioning the status quo, considering potential alternatives, trying out innovations and testing ideas by careful collection and analysis of data? In effect, there is no critical difference that prevents practitioner evidence-based practice counting as research. However, there is an expectation that undertaking something formally characterised as research implies a commitment to publication and dissemination. That is, it is usually expected that research should be reported to others. There are a number of considerations that need to be taken into account when you are thinking about publishing your research. All research (and teaching) needs to be informed by a strong ethical framework, and particular considerations come into play when one is publishing accounts of classroom work. First, however, we might consider what publication (putting into the public domain) means for research undertaken by a schoolteacher or teacher group. I would suggest the following things do not qualify formally as publishing research: talking to colleagues about your classroom work during the break between lessons; discussing things that you have tried out in your classroom at a department meeting to inform your colleagues in the school; zzpresenting examples of innovative practice in general terms as part of an internal professional development day, or in working with less experienced colleagues or student teachers; zzmaking general comments about things that have or have not worked for you in the classroom on blogs and social media outlets. zz zz

However, even in these relatively internal or informal contexts, it is important to remember the rights of the learners in your classes. Under the principle of copyright, any author or artist has rights relating to the use of texts or diagrams (or other designs) they have produced – including those 11-year-old authors and artists in your class completing a homework task. Being their teacher does not give you the right to publish work your students legally own. Talking to another teacher about some aspects of a student’s work within the context of the normal processes of teaching, planning and assessment within the school is entirely reasonable: posting a scan of a student’s diagram on Twitter without permission is an infringement of the learner’s rights (even if you do this to praise them!). They might not mind, indeed they might even be pleased, but technically they (or in practice their parents) would have recourse to law if they were not happy with this use of their work. Similarly, even in internal and informal settings, it makes sense to use examples we discuss anonymously, unless the focus of the activity requires otherwise (a case conference about a student; a selection of student work for a prize). This may require more than simply not using names. To talk about ‘a’ student in your class with visual impairment may in effect identify the particular learner you refer to.

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MasterClass in Science Education Clearly other settings are more public: presenting at a conference; talking at a meeting for parents of prospective students; writing an article for a periodical; writing a book – or a thesis for a university degree. Often teachers’ research theses are placed in a library (even if sadly most are seldom consulted). Generally, your students’ productions (texts, diagrams etc.) should be used in such circumstances only with voluntary, informed, consent – that is, with permission freely given by someone who understands what they are being asked to agree to. As most schoolchildren are legally considered minors, parental permission is often needed. In practice, most children and parents are very cooperative in this regard, but this should never be assumed without checking. Technically, the copyright owner is entitled to ask for a fee for the use of their work in this way. That’s very unlikely, but you do not want to find out that you are being charged a fee only after you have published something. People in some jobs give up their rights to copyright in material they produce as part of their work (in consideration of a fee or salary). A civil servant drafting a government document is considered to be producing a ‘work for hire’ and the copyright remains with the authority for which they work. Schoolchildren are not paid for their work so would not be considered to have sold their work in this way. University academics normally retain intellectual copyright in works they produce as part of their scholarship, so an academic who researches a topic to prepare lectures is free to write a book based on this scholarship and offer it to a publisher for financial reward (albeit the royalties from most academic works are pretty modest). This is an issue that is well established in the university sector but which is less commonly explored for schoolteachers. Probably a scheme of work produced for the teaching department would be considered to belong to the school, but the teacher’s own lesson notes and plans are their own intellectual property. (Of course, expectations may vary from country to country: in some countries, teachers are formally considered to be civil servants.) Many teachers may have values that suggest that as far as possible all educational material should be copyright waived and freely shared; however, the law protects copyright for those authors who do not wish their work to be exploited by others. In summary, the professional teacher engages in classroom-based enquiry to inform their own practice, and shares their experiences with colleagues. Sometimes when research is formally structured and offers insights of wider value, it may be appropriate to seek wider publication. This is one important way (if certainly not the only way) a classroom teacher can take on a leadership role in science teaching. Students, however, should not be participants in published research unless they have given informed consent following a careful ethical review. This will likely involve the identification of a suitable senior colleague as a ‘gatekeeper’ when a teacher is working with their own students (Taber, 2013a). Student participants need to be offered confidentiality and anonymity, and their copyright in their own work must be respected.

Enquiring into Science Teaching

Suggested further reading There are many books about educational research methods to support those wishing to undertake enquiry into their own practice or institution. The following was prepared with classroom teachers, and teachers in preparation, in mind: Taber, K. S. (2013). Classroom-based Research and Evidence-based Practice: An Introduction (2nd ed.). London: Sage.

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Part II Perspectives on Science Teaching

Critiquing the Science Curriculum

Chapter outline Why teach everyone science? Making curriculum choices The student experience Meeting curricular aims within a more integrated curriculum Suggested further reading

25 34 35 40 43

Why teach everyone science? It is very likely that if you are reading this book you think it is a good idea for science to be taught in schools, and you probably consider that all students should learn some science as part of their schooling. However, you may not have spent a lot of time asking yourself why you think this. Our intuitions about the world are often well grounded in our experiences, and may offer valuable insights (Brock, 2017). Nonetheless, as professionals, it is important to notice when we take things for granted, and check we have good reasons to back our intuitions. If you are to teach science to young people, especially young people who are required to attend school and study science (whether they want to or not), then it is useful to have given some serious consideration to what gives society the right to set out such requirements. There was a time when it would have been sufficient to argue that adults have decided this should happen (that is, adults know best) even if ‘because I say so’ is seldom a convincing reason for the child. However, there are now international conventions on the rights of children supporting the reasonable principle that children should have a say in any decisions which impinge on their lives. Whilst this is not generally considered to imply they can simply choose not to

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MasterClass in Science Education go to school, adults are, quite rightly, expected to give careful consideration to the decisions made on behalf of children and be able to justify those decisions. There is now often a focus in schools on the importance of what is called ‘student voice’ or ‘pupil voice’ (discussed later in this chapter). If we are going to argue that all children should be taught (i) the formula for kinetic energy, or (ii) to balance chemical equations or (iii) to explain the difference between meiosis and mitosis, then we should be able to provide a strong rationale for why we think this is so important. Science teachers have usually themselves enjoyed learning about such things, proved good at doing so and indeed built a career on their success – so our personal feelings and experience may be atypical. (Perhaps there were other school subjects you did not enjoy, you did not find interesting and where you cannot remember ever having found any situation or context that allowed you to apply what you had learnt after leaving school.) Moreover, unless we have worked through our rationale for requiring children and young people to learn science, we ourselves (collectively as a science education community or as school teaching departments or as individual classroom teachers) will not be in a strong position to decide what science we should teach, and what aspects should be most emphasised. This chapter explores this issue of the nature of the school science curriculum. Many arguments have been made for the importance of education, and of science education, to young people. Here I will discuss some (overlapping) themes from such arguments. I will label these as: the pipeline argument: the economic driver the choice argument: the aspirational driver zzthe liberal argument: the cultural driver or the developmental driver zzthe citizenship argument: the democratic driver zz zz

We should not align ourselves with just one of these options – we may to some extent agree with them all. However, these different rationales may suggest different curriculum priorities, different sets of content to be taught and learnt, and different ways of presenting science in the school curriculum. You should therefore give some consideration to the relative importance of these different ‘drivers’ – which you feel are most important in deciding how to teach science and what science to teach. You should also consider if you would balance these considerations differently for different groups of learners you might teach during your career.

Maintaining the pipeline One argument you may have come across is concerned with the supply of personnel to take up roles in the economic system. The future economic prosperity of society depends on

Critiquing the Science Curriculum producing enough electrical engineers, doctors, industrial chemists, computer technicians, laboratory assistants and so on. From this perspective, schools are part of a ‘pipeline’ that must provide staffing of the right specialisms, the right level of training and in the right numbers to provide the qualified people to do the jobs we all rely upon. Schools need to provide enough suitably educated people to enter degree courses, apprenticeships and so forth. Although this may be considered to be an ‘economic’ driver, that does not mean it is just about supporting multinational corporations to make large profits for their shareholders. If there is no qualified pharmacist available, then our medicines do not get dispensed. No one wants the lights to go out because the power station management cannot find qualified engineers to employ in safety-critical positions. Moreover, it is the qualified scientists and technologists of the future who are passing through schools now who will hopefully provide us with more energy-efficient technologies, more effective medicines, ‘greener’ materials, new strategies for protecting endangered species, new crop strains better at thriving in arid conditions and the like, so this is certainly an important consideration. The real issue here is to what extent the school curriculum should be led by the needs of professional and vocational training (see Figure 2.1). Enquiry into practice: Are we servicing a workforce pipeline? The notion of a ‘leaky’ STEM pipeline is sometimes discussed in policy documents, but does this influence thinking about science education among teachers? Metaphors, if they are not critically analysed, can be habitually adopted and may influence our thinking. zz

zz

Is the pipeline analogy useful, or does it focus attention too much on a limited aspect of what science education should be about? What might a ‘leaky pipeline’ potentially imply about those who ‘leak’ out of the pipeline into other areas of work?

This could be a theme for a study that interviewed teachers in a school (individually or in groups) or observed a focus group discussion. This exercise might inform a departmental meeting or development day activity considering how the department should develop and present the science curriculum (which courses, and which elective elements, to offer; how to present options to students and parents; etc.) Such an enquiry would likely be interpretivist (looking to make sense of how people perceive and understand aspects of their worlds). It might be idiographic (acknowledging and valuing the unique positions potentially adopted by individual teachers) or phenomenological (seeking to identify the range of perspectives and positions adopted within the department). Such an enquiry might adopt a personal constructivist position (focusing on individual meaning making of different teachers) or a social constructivist perspective (giving particular emphasis to how individuals negotiate their positions in interaction with their peers, and influenced by the wider culture – such as institutional norms of customs and practice in the department/school; the national curriculum context; the expectations of inspectors, parents etc.) Alternatively, if the department decides to review practice, the enquiry could adopt a constructionist perspective (exploring how the individuals in the department work together to create something new, such as a revised scheme of work).

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MasterClass in Science Education

Figure 2.1  Science education seen as a means to provide a background to (and pathways towards) vocational and professional preparation for a minority of students.

Providing opportunities for all A related argument looks at the role of school in preparing people for the world of work from the perspective of the individual learner, rather than the overall needs of society. Any young child who decides they want to be a doctor or a research scientist or an astronaut should be given the opportunity to work towards that goal. That is not to say schools are responsible for making dreams come true. Not every child has the aptitude for surgery for example, and there is presently a limited demand for astronauts, even if the vacancies tend to attract a disproportionate amount of attention. However, no child should be denied the chance to work towards their aspirations. If we think it is obvious that some groups of students are not suitable for certain roles in society, then it might be useful to recall that there was a time (within living memory) when many schools offered girls only biological sciences as chemistry and physics were judged unsuited (or irrelevant) to women. From this perspective, schools need to offer courses such that those children who are able to succeed at them can become suitably qualified to move on to whatever form of further or higher education and training they choose. This is what I mean by the aspirational driver: no one should be denied the possibility of a particular career direction because ‘my school did not offer that’ or ‘at our school there was no one to teach towards the higher levels/grades’. In England, at the end of the last century, many secondary schools did not offer their pupils the option of ‘triple science’ (or ‘separate sciences’), arguing that the National Curriculum required them to offer only the more limited ‘double science’ course. Whilst strictly this did not prevent students from proceeding to advanced study after completing their school examinations, it often meant students joining college classes where some of their classmates had studied additional topics (with their associated opportunities for reinforcing basic concepts and principles) that they had not met in their own school courses, putting them at a disadvantage from the start of their college courses. Even when the curriculum seems to offer the required opportunities, these rely upon suitable teaching expertise. Some physics specialists may be enthusiastic, knowledgeable

Critiquing the Science Curriculum and skilled teachers of biology topics (and vice versa). However, if staff timetabling relies on covering lessons with some kind of science teacher because the school cannot attract enough staff in a particular specialism, then students may not be properly supported with the opportunities they need to demonstrate their full potential to progress in a subject (see also Chapter 15).

Providing a liberal education A different starting point sees education as preparation to fully enter the wider culture rather than focusing on opportunities for work and careers. The culture of any society includes a range of areas of activity that are valued, so we might include, say, dance, music, fine art and literature as part of a culture. The argument is not that schools should prepare the students to become professional dancers or novelists, but rather that the cultural driver suggests that for a person to take a full part in society, to be educated in that context, they need to have some familiarity with, say, dance – to have some ‘literacy’ in relation to dance. Whether that means familiarity with a canon of ballets or the main forms of ballroom dancing, or both, or something else entirely, then has to be decided. But someone who leaves school knowing nothing about dance as a form of cultural activity does not have a rounded education. The author would be an example of that. I do not recall dance ever being mentioned during lessons at school. I recall one single session when I was asked to do any dance – and that was at a local teacher training college where some primary-age students went on Friday afternoons for alternative educational experiences (Bridges, 1969). What exactly needs to be included in such a schooling will reflect the particular culture. At one time the standard university curriculum in Europe meant all undergraduates began their course by studying grammar, logic and rhetoric; but culture moves on, and this is no longer seen as a universal foundation for degree courses. There is a strong argument that in modern, technologically advanced (and dependent) societies, science is a key part of culture. Science features on the television news, in the newspapers and magazines and in a wide range of documentaries and the like. Moreover, other cultural forms such as novels, theatre, television dramas and films assume a familiarity (if not always a detailed and entirely accurate familiarity) with science. The scientist and novelist C. P. Snow gave a popular lecture in 1959 broadcast on UK national radio which popularised the idea that there were ‘two cultures’ in British society (Snow, 1959/1998): those educated in arts and humanities (who often dominated politics and the civil service in the UK, where Lord Snow had held an influential role in science policy work after having worked as a research chemist) and those who knew about science. Snow’s point was that there was an asymmetry where scientists who were not familiar with, say, Shakespeare’s Hamlet or a Mozart horn concerto would be considered ignorant. Yet it was perfectly acceptable at polite dinner parties for the highly educated to admit no knowledge of, or indeed interest in, say, the second law of thermodynamics or the Wallace line. Snow’s

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MasterClass in Science Education point was not that everyone should have a special expertise in science, but that being educated in a modern society should include familiarity with science as much as with fine art or poetry. Educated people should be able to have an intelligent conversation about symphonies and landscapes and also about scientific discoveries and theories. Probably the situation has improved considerably since Snow’s ‘two cultures’ lecture. Perhaps, in part, this is due to those areas of science that have caught popular imagination – genetics, quantum theory and relativity for instance – and perhaps, in part, is due to the cultural recognition given to sci-fi characters such as Kirk, Spock, Picard and Data, with their phasers, matter transporters and warp drives. The popularity of television shows that feature forensic science is also a positive sign (even if they often tend to make such work seem much more cut and dried – no pun intended – than it is). Despite this, there remains among some groups in society a view that science and mathematics are inherently difficult and only geeks can be expected to have a strong enough interest in these areas to hold a meaningful conversation about them. Yet I expect most readers of this book found some other school subjects more difficult than the sciences. Even in the internationally very popular comedy show The Big Bang Theory, which features scientists and engineers as the main characters, this stereotype is strong (and the only leading female character in the early episodes was presented as largely uninterested in, and unable to understand, science). It is relevant here that science education is not only concerned with the cognitive domain (Bloom, 1968). Knowledge and understanding are very important. In most areas of science manipulative skills and observational skills are important, and so science educators are also concerned with the sensorimotor domain. However, they also need to consider the affective domain (Krathwohl, Bloom & Masia, 1968). We want learners to develop positive attitudes to science, and science education can contribute to the development of a coherent system of personal values (Taber, 2015b). Science also has great potential to engage the aesthetic sensibilities of students. Some are repelled by dissection. Many will find beauty in flowers, trees, shells, crystals, galaxies, rainbows and so on. Aesthetics may seem to have more to do with the arts and humanities, but science is the best placed curriculum area to help young people develop an aesthetic appreciation of nature (Kind & Kind, 2007). This is well recognised in Japan, where early education includes a curriculum subject which encompasses science but is just as much about developing a respect for, and relationship with, nature and the environment (Sumida, 2013).

Supporting the development of the whole person Supporting a young person to become a full member of their culture may (like the economic driver) seem to have a focus on what is good for the society in general; young people being encultured into adult society. Yet providing a liberal education is also about supporting the development of the whole person – a person who can think rationally but also creatively (both essential in science); a person who understands things and mechanisms but

Critiquing the Science Curriculum also people and groups; a person who can solve problems and make logical choices, but also appreciate different perspectives and enjoy aesthetic experiences that seem to transcend any obvious logic. This person can empathise, as well as rationalise; can imagine the fantastic, as well as the probable cause; and can be sensitive, as well as sensible. The graduate from such an education is ethically and morally – as well as cognitively – developed. A term that is used for education in some parts of continental Europe is Bildung, which is perhaps best understood as ‘formation’. Education supports the formation of character, through the maturation of the learner both as an individual and as a member of a society. From this perspective, a liberal education is as much about supporting individual development as it is about induction into culture. This might appeal to those who entered teaching to improve the world and help people (as well as teach some science!), especially where this is seen as a ‘critical’ or emancipatory mission, that is, to help and empower the less fortunate groups in society. A criticism sometimes made of schools and education systems is that they work to reproduce the culture (including class and other distinctions); that is, they are conservative agents that train the young to think like, and accept the values of, previous generations. Most schools espouse societal values; for example tolerance of differences. If these values are being instilled into the young, few of us would complain. We all probably approve of schooling reproducing the values we like, but would object to ‘indoctrination’ into values we abhor. Schooling does change over time, but this is often a reflection of societal changes rather than the schools themselves being in the avant-garde. I had lessons in woodwork and metalwork at school, alongside the other boys in my form, whilst the girls were doing domestic science (cooking and needlecraft). Such a division now seems inappropriate. Perhaps the best protection from schooling being seen as a process of maintaining the status quo is to adopt a mentality that fits the notion of education as Bildung, character formation. Schools should introduce young people to the recognised aspects of their culture, but do so in a way which always values the development of individuals who will learn to take on responsibilities in the light of their own priorities and values. It may not be immediately obvious that science is the best curriculum area to support this, but if we think this is central to our educational purposes, then we will shape the science curriculum to provide opportunities to support this aspect of character development. That may link with our final perspective.

Science for citizenship The final argument to be considered here (viz. the democratic driver) suggests that people living in a modern democratic society need to be able to go beyond having intelligent conversations about science to making principled decisions based on an understanding of science. Even those who will never work in an area directly engaging with science will make important decisions as moral and political agents that can be made intelligently only if they are informed by science.

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MasterClass in Science Education Many of us face important decisions for ourselves, or for our dependents, about medical treatment. Given certain diagnostic information, we are told about certain likelihoods of unwanted and more desirable medical outcomes. One or more possible treatments may be available – perhaps including surgical and medical options. Each possible treatment offers some likelihood of improved outcomes, but may also have side effects or risks. What should we do? Having a good understanding of the background to the problem, and the risks and benefits of possible treatments, cannot tell us what we should do – but it can at least ensure we make an informed decision. More generally, we need to make everyday lifestyle choices about diet, and exercise, that involve balancing costs and potential benefits. Enjoying chocolate, or potato chips covered with salt, is a valid aesthetic consideration, but should not be the only basis for dietary choices. We also make decisions as consumers – should we pay more for the shampoo that contains some special protein, or for the coffee that we are told is in the more environmentally friendly container? Just what benefit will there be to having thicker loft insulation, and when can we really expect to recoup the costs of its installation? Understanding the science gives a basis for informed choices. This also applies to the more explicitly political realm. Should we support the party intending to build more nuclear power stations? Should we commit leisure time to campaigning for an environmental group? Should we oppose the killing of badgers when the cull is intended to limit the spread of bovine TB? Some of these issues relate to questions where science might be able to offer good guidance towards a sensible decision. We might ask, for example, about the evidence that protein added to a shampoo will do anything other than get washed away when the shampoo is used. Other questions are more difficult, and science offers less definitive advice. For example, consider the hypothetical argument that the historical evidence shows that – statistically – nuclear power leads to less loss of life than power generation from fossil fuels (where many have died in coal mining and drilling for oil), but that in the very unlikely event that there were a major accident involving nuclear power a great many lives could be lost. Even if the argument and evidence for such an assessment convinced us that it was trustworthy, it still might not be clear what the best path of action should be. Is a very small chance of losing many lives acceptable if on balance selecting that option is most likely to save lives? Or is a more nuanced evaluation needed? Science can help us predict (on the basis of current best available evidence) the likely ‘average’ result, but not the level of risk we might consider acceptable. It is clear that in many major issues involving science, knowledge and understanding of the technical issues is necessary, but not sufficient, for wise decision-making. When one is considering what are called socioscientific issues (Holbrook & Rannikmae, 2017), scientific knowledge supports, but underdetermines, decision-making – as that also requires the application of extrascientific values (see Figure 2.2). Consider a hypothetical (but not unrealistic) case where industrial development would be at the cost of destroying habitat that scientists suggest would likely lead to the loss of a rare species  – but

Critiquing the Science Curriculum one that was not considered especially significant in the ecosystem. From an economic, and even environmental, perspective, the costs of development in terms of species loss are minimal (and perhaps there are significant benefits of the development going ahead), but there is a moral issue about whether humans should deliberately bring about changes that are expected to lead to the loss of a species. Science cannot tell us what is right or wrong – it can only put us in a position to make an informed judgement. A general principle that humans should avoid eradicating other kinds of living things was widely considered secondary when scientists worked to remove smallpox from the natural environment. Most people are not going to be able to effectively draw upon their scientific knowledge and understanding and apply this when evaluating social issues if their school science education has not supported them in developing the skills to do so. This is analogous to teaching students about the equations of kinematics, or the use of the flame test in identifying cations in salts, or the use of a branching key for identifying biological

Figure 2.2  Aristotle identified different forms of knowledge related to theory, craft know-how and wisdom in applying ethics in practice.

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MasterClass in Science Education specimens – but never giving students the opportunity to have experience of applying the ideas, and rather just assuming they would be able to do so if asked (in an examination, for example). Similarly, if we want students to understand public debate about contemporary scientific issues such as climate change, then they need to appreciate how science works through processes of argumentation about evidence (Adúriz-Bravo & Chion, 2017). If we teach about the consensual models and theories of science only once they have become well established, then real ‘science in the making’, with its claims and counterclaims will seem very unfamiliar. Most informed observers consider there to be a wide consensus among scientific experts that the climate is changing, and that human activity is a contributing factor. There are a few dissenting voices, and ongoing debates about such matters as how quickly change is occurring; how atypical the current rate of change is; and just how much of the change is down to anthropogenic inputs into the atmosphere. That diversity is normal and to be expected in an area of ongoing science, but this is not the image of science given by traditional science teaching, which often presents science as almost factual; as proven; as agreed upon by scientists as a whole. This has been described as presenting science as a rhetoric of conclusions (Schwab, 1962). Students who have experienced only formal science, represented with the authority of school science, as a set of clear-cut and unproblematic principles, laws etc. will find the media reports of climate change science to offer a confused and contested state of affairs. The climate debate may well seem to suggest that scientists simply do not know whether climate change is real, in which case perhaps rather than act upon what is ‘just theory’, it may seem we should better wait until climate change is proven or not. Yet scientists never know for certain, and do not really ‘prove’ their ideas (see Chapter 9). Climate change is theoretical, yet in many areas of science, theoretical knowledge is the end point (see Figure 3.1), even if, in principle, such theories remain open to challenge in the light of new evidence or a novel way of understanding existing data.

Making curriculum choices These different drivers may potentially suggest different priorities for developing the science curriculum. If, for example, we want to prepare young people so that they will be able to undertake socioscientific decision-making after they leave school, then teaching technical aspects of science decontextualised from their relevance to major societal issues will surely fall short. A major issue in education is what is known as ‘transfer’ of learning (Goldstone & Day, 2012) – to apply what is learnt in one situation to a novel context. For example, students may struggle in science classes to use mathematics that they are comfortable applying in mathematics lessons. How much more will young people struggle to make sense of scientific principles in socio-economic contexts if they have never been introduced to thinking about the role of science in decision-making in such contexts.

Critiquing the Science Curriculum Enquiry into practice: Exploring student difficulties in applying mathematics in science A teacher who was concerned that her students did not seem to be able to apply basic mathematical ideas and procedures in contexts arising in science classes (even when those same students were able to successfully use the ideas in mathematics lessons) might consider exploring what makes some students more successful in this aspect of science when others struggle. Such a study could look at a number of potential factors. One issue might be working memory (see Chapter 5), as there is strong research that all of us have very limited capacity to ‘mentipulate’ a range of different units of information at once (Stamovlasis & Tsaparlis, 2000). A mathematics problem that fits within working memory capacity may suddenly seem more complex when it is met in science and is embedded in contextual information. Perhaps students lack the procedural knowledge, or the skills involved in identifying and decontextualising the numerical information that needs to be processed mathematically, and then recontextualising the calculated answers (explaining why some students accept calculated answers that are clearly ridiculous in relation to the context – such as a man of mass 10 mg or a cyclist moving at 250 m s−1). Alternatively, perhaps some students have difficulties because of the way they compartmentalise knowledge learnt in different parts of the curriculum, making it more difficult to access things learnt in ‘other’ subjects. This has been found among successful, high-performing students, such as the college student who rejected the author’s suggestion in a chemistry lesson to think about a related practical she had recently undertaken in her physics class: her response was that it was difficult enough to think about chemistry in chemistry lessons, without being asked to consider physics (Taber, 1998). If this is an issue for some students, when others seem ready to make links and construct analogies across the curriculum, we might wonder if this is some deeply established feature of thinking which the teacher is unlikely to challenge, or a learnt strategy to cope with schooling that might be challenged by a suitable intervention. Perhaps compartmentalising learning in local packets of knowledge linked to a particular lesson or context is actually a sensible strategy when the school curriculum seems to be taught and assessed as a series of discrete topics. There is potential here for classroom research that explores the nature of the learning barriers operating for different students, and for studies that develop and evaluate interventions designed to respond to those barriers.

The student experience Most of the discussion above focused on the role of science education in preparing learners for their future, whether as advanced students, in seeking employment or making decisions as consumers and citizens. However, it is also important to consider how students themselves experience their science lessons. As suggested above, it is accepted internationally that just

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MasterClass in Science Education because a person is not yet an adult this does not mean they do not have the capacity to make an input into decisions which affect their lives. Of course, it is equally true that children depend upon wise adult guidance in learning to be responsible decision-makers, so there is a balance to be determined in relation to what extent decisions about school should be influenced by the views of pupils. A position widely adopted is that children have a right to be consulted and for their views to be considered, even if final decisions are vested in (‘responsible’) adults such as parents and teachers. Some approaches to learner consultation, such as having school councils and form/class representatives, go back many decades, even when student input into policies about curriculum, pedagogy and so forth was very limited. Students might be consulted about the school dress code or the name of a school newspaper, but do not usually get to decide which subjects are included in the curriculum or how teachers should teach. A common complaint from students is that they are not consulted on issues relating to teaching and learning. It is not suggested here that students should determine the timetable or teaching approaches, but it has become commoner to find ways to involve students in discussion on such matters.

Student voice Indeed there has been something of a movement in what is sometimes known as ‘student voice’ or ‘pupil voice’ (McIntyre, Peddar & Ruddock, 2005) that argues that school pupils are major stakeholders in what goes on in classrooms so need to be involved more in decision-making. Many teachers will understandably think that most pupils are not only minors (below the age where they legally obtain major responsibilities) but also amateurs as pedagogues, rather lacking in the professional training and experience that teachers have. Teachers should not abdicate their professional responsibilities. Poor learning outcomes cannot be defended on the grounds that the students chose the learning materials and activities – and chose poorly. However, teachers have themselves been encultured into certain norms and expectations, and we may take it for granted that the familiar (i.e. whatever is familiar) is the way things should be done. A colleague told me of how, in Sweden, the teacher and class agree at the start of the course how and when the assessment will take place. That seems very odd for someone who has been educated and taught in England. The teacher can usefully seek feedback on what pupils enjoy, consider interesting, find engaging and so forth. Building information on the pupil experience into the planning process, alongside other considerations, can be useful. There are many occasions when a teacher may be considering teaching particular material in one of several ways, or locating teaching within one of a number of contexts, where knowing student preferences may be helpful in choosing between viable options for particular classes. This is not delegating responsibility, but rather including student perceptions as one among a range of factors to be considered when making teaching choices.

Critiquing the Science Curriculum Enquiry into practice: What do pupils understand as the purpose of science education? Those of us working in schools, whether as teachers or students, can easily take a great deal for granted. There are many things we do not think to question. Do we know what students might think the purpose of learning science is? Do many of them assume that science lessons are only really important to those who want to do more science after leaving school? An enquiry might involve asking a sample of students, perhaps individually, perhaps in small groups, about why they think they are asked to study science, and the reasons (if any!) they think they should have to study science. You could also ask them about when they think they should be allowed to drop science or at least specialise within it (and why). Student suggestions could be used as prompts in other interviews, or focus groups: ‘One student I asked told me … what do you think about that idea?’ Do you expect students would suggest any of the rationales presented earlier in this chapter? You could prepare cards with succinct statements drawing on the different rationales discussed in this chapter. Students could be asked to read the cards, and comment on them – or perhaps sort them according to which ideas they thought were more or less important. Methodological note: Choosing between individual interviews, group interviews and focus groups (a kind of observation of group activity and discussion) should be made carefully, as they give different kinds of data. Perhaps a combination of methods might be useful (offering potential for triangulation – seeing if the interpretations of evidence from different data sources lead to similar inferences). If you are going to use student comments or cards with rationales as foci in research sessions, it might be better to do this only after asking students more open questions to see what their unprompted thoughts might be.

Giving pupils choice A particularly useful strategy that can sometimes be employed is in giving students choices within the classroom. Where this is feasible it offers a number of strengths. One is that of simply giving students an input and a sense of their views being valued. Another is that it allows individual students or groups to learn material through an activity or in a context they find particularly engaging. Another advantage links back our fundamental purposes of education and schooling. School needs to produce young people able to make responsible decisions. Giving students real decisions within their schooling (i.e. within a supportive context) is important preparation for life. In many school systems, it has long been traditional to give pupils some choice in subject options or academic slant (perhaps a science or humanities focus) at some point in their school career. This is a rather important decision, especially so for pupils who are not used to being given any choices about their learning. It seems sensible that students should be given some prior experience as preparation for making such critical decisions. This is also an issue where social background may be important. Some children will come from homes where parents or guardians are knowledgeable

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MasterClass in Science Education about career options and the subject choices that may support them; where such issues have been regularly raised in conversation over many years before students reach a decision point; and where the parents or guardians are well aware of the importance of such decision points and seek to engage their charges in meaningful conversations to support their decision-making. Some children will have been encouraged to have strong career aspirations, and to consider a broad range of options. Other children will come to these major decisions without the same resources to support them – they might be said to have less ‘social’ or ‘cultural’ capital if they lack the home relationships to facilitate effective parental guidance or if the family lacks the know-how to offer such guidance, respectively (Lyons, 2006). Enquiry into practice: What are pupils’ perceptions of the science-related career options available to them and of how subject choices may support or close down options? Your students probably know that science is needed to study medicine – but what about its relevance to architecture? (Those students with more cultural capital will recognise this: but perhaps not others.) When we teach science topics we assume students may have misconceptions and that it is important to be aware of their thinking to inform our teaching (see Chapter 6), but might we just take for granted how much they know about science-related careers and qualifications? Could an exploration of your students’ knowledge and understanding in these areas help you support them in making sensible career-related decisions?

Students generally do value being offered some level of choice, and so this can be motivating and enhance engagement. Offering choices may not always be possible without compromising other considerations, so the recommendation here is to look to see where and when there are opportunities to do so – it may be surprising just how often this is the case. As an example, consider a lesson that was taught to pupils around fourteen years of age focused on the idea of a scientific explanation. Explanation is core to scientific work, and if our purposes for science education relate to students understanding science (as an area of activity), as well as understanding some specific science, then we might want students to appreciate the nature of an explanation – and have some criteria they can use to evaluate explanations that they might construct or be asked to consider. It is clearly possible for a teacher to teach about scientific explanation selecting from contexts from across the sciences. The lesson was prepared with student activities that offered choice of context (Taber, 2007a). The students appreciated being given some choice in selecting the examples they would look at.

Examples from science learning The ‘cost’ of this choice was an increase in lesson preparation time as alternative versions of activities had to be prepared. Yet this need not be a major extra commitment. Once the framework for an activity had been designed, several examples had to be prepared. Yet it is likely that a teacher would always be considering a range of possible examples they might use with a class, and a wise teacher (cf. Figure 2.2) always has some backup examples in

Critiquing the Science Curriculum mind in case problems arise with the selected example. If students are unexpectedly struggling with an activity, the teacher may make a ‘live’ (‘online’) decision to change a lesson plan. The examples that had been intended for students could instead be worked through by the teacher leading a class discussion, and then another example could be given for students to work on. The idea that lesson plans have to be carefully designed, but open to flexibility in terms of responding to how the lesson is proceeding is discussed further in Chapter 7. Even when one is starting out on teaching a topic, it is sensible for lesson planning to include redundancy to avoid running out of material if students work faster than expected, or prove to have already mastered the material, or if chosen examples or activities prove to be unproductive. Moreover, experience with teaching and reflecting on topics, and ongoing reading around science and science education, are likely to suggest alternative examples and contexts for many topics. So even when a first iteration of a lesson does not offer choices to students, these may be added later when one is subsequently revisiting the lesson plan for future classes. Sometimes students are set mini projects (often in groups) to research and present work on some topic. If the theme was, for example, endangered species, then students could be given wide scope to select examples. The different examples can be presented to the class (offering learners opportunities to develop communication and presentation skills) – giving a range of contexts for the teacher to draw out and emphasise the key teaching points – which are likely to be general principles that apply across a wide range of examples. There are also techniques for teaching topics through a ‘jigsaw’ approach where different students or groups of students are tasked with working on some aspect of a larger activity, and where, after they have worked on each separate part, the different ‘pieces of the jigsaw’ are brought together by each student or group, explaining or demonstrating their aspect to the larger group (Berger & Hänze, 2015). There is an aphorism shared by teachers that they often only really understood a topic when they came to teach it to others; this suggests that if we want our students to engage with material to support deep learning, we might – at some carefully judged level – ask them to take on a similar teaching role (see Chapter 15). It may often be possible in such activities to give students some choice of the component they work upon. It is important to offer choice without limiting the learning experiences students have. For example, in some activities, there may be different roles (perhaps chair, or spokesperson or scribe), and it would not be good practice to allow some students to always take the same roles – think, for instance, of the hypothetical pupil who chooses to always record results in laboratory work, but never to manipulate the apparatus and materials. One should also be wary of students who may have got the idea that they have a particular ‘learning style’ which suggests they should best undertake particular types of learning activities. The notion of learning style can be a valid one, although only a few of the models that have been developed have strong empirical evidence (Coffield et al., 2004), and it is an idea sometimes trivialised in ways that are not helpful in the classroom (such as notions that some learners are primarily visual, auditory or tactile learners).

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Meeting curricular aims within a more integrated curriculum If we consider curriculum less as a list of subjects to be studied and more as the means we employ for meeting curricular aims such as those explored earlier in this chapter, then this raises the question of whether we need to package the curriculum (a tool for achieving overall educational goals) in terms of a timetable that is partitioned into discrete subject headings such as mathematics, science, history, … or indeed biology, chemistry, physics. One tradition associated with the ‘liberal’ perspective (see above) might suggest that our culture is generally understood in terms of spheres of activity such as science, fine art, literature, music and politics, and that traditional subject disciplines reflect these divisions at least to some extent. However, if our key aims relate to supporting the development of future citizens, then it may be less obvious that such distinctions are the best approach. For example, if we think it is important to teach about socioscientific issues, then this requires learners to apply scientific knowledge in social contexts that might normally be learnt about in humanities subjects such as economics, social geography or history; and appreciating different value systems (something that might normally be considered in subjects such as religious education or philosophy, or in areas such as personal, social and health education). Perhaps such teaching is best undertaken by sometimes working in cross-disciplinary teams that bring different expertise and pedagogic skills (Rennie, Venville & Wallace, 2012). Questions about curriculum integration then go beyond the question of whether and when science itself should be taught as a unitary subject or through separate timetable slots for named science disciplines. This raises the question of why in so many countries the school timetable is still organised along traditional subject lines. Perhaps, it might be conjectured, because this is educationally best. But a cynic might suggest that school systems carry a lot of institutional inertia, and there is a tendency to carry on doing things the way we always have (after all, they did it that way when the teachers went to school, and it seems to have done them no harm). We saw above that schools may tend to support ‘cultural reproduction’ rather than ‘cultural innovation’: that is, that schooling can (deliberately or inadvertently) become an instrument of the establishment which ensures that young people are inducted into the norms of the existing system, so working to maintain the status quo (Nash, 1990). One view would be that a more integrated form of curriculum delivery system (a timetable not based on discrete subjects) could be a better means of meeting educational goals (Broggy, O’Reilly & Erduran, 2017). So it might be argued that we could achieve more by students spending extended periods engaged in studies of issues and topics – perhaps based on project work that makes learning more authentic (as students are always working towards some substantial product at the end of a unit). However, the cynic might suggest that schools find it just too difficult to plan for such an approach in terms of teacher development and recruitment, and timetabling of teachers and resources (laboratories, workshops, libraries,  etc.).

Critiquing the Science Curriculum We  might also wonder how different newspapers might label such a proposal depending upon whether they would wish to present the idea as sensible or risky, as deserving support or ridicule, as groundbreaking and progressive, or as revolutionary and crackpot. This remains an open question in education, and one that is subject to ongoing exploration. There would almost certainly be some educational value in teaching students (at least some students, at least some of the time) through cross-curricular topics and projects, despite possible practical challenges. Yet there is also value in having subject specialisms, with specialist teachers controlling their own schemes of work and associated resources. Some students certainly value the variety of the timetable and look forward to the times in the week when they have their favourite lessons. Probably there is value in having subject-based timetables (and of course if our main driver for curriculum is ‘maintaining the pipeline’ this may seem the obvious choice) but with some opportunities for collapsing the curriculum and engaging in more integrative study. This is not a new idea. At the time the present author went to primary schools, many teachers taught through topics and projects (rather than subject-based lessons) much of the time. The author also attended a subject called ‘integrated studies’ in lower secondary school which taught English through topics that drew on the humanities (e.g. half a term learning about castles; half a term working on a public enquiry for a hypothetical new airport development). When I was preparing for teaching, one of my placements was in a school that collapsed the timetable for 11- to 12-year-olds for the final half-term of the school year, and I spent my last week of ‘teaching practice’ (as it was called then) in a field living in tents as part of this approach.

Science as part of STEM (or STEAM) education In recent years, a ‘STEM’ education agenda has been developed in many national contexts (Freeman, Marginson & Tytler, 2015). STEM usually stands for ‘science, technology, engineering and mathematics’ – a group of subject areas considered to have much in common. Mathematics is clearly essential to the other STEM areas, and science is similarly essential for the more applied areas of technology and engineering. The logic of identifying STEM is especially relevant to the ‘pipeline’ perspective on education. School is part of the pipeline that produces the scientists, engineers, medics etc. that society requires – and this pipeline relies on enough students doing well at STEM subjects in school and choosing to progress with study of these subjects. School science and mathematics, in particular, are core subjects for the pipeline. This is not to suggest there are not those who champion STEM from different perspectives. For example, concerns about female under-representation in areas such as physics and engineering may encourage some STEM advocates from an equity perspective: if girls come out of school less prepared, or less motivated, to consider careers in areas such as engineering, then perhaps the system is not offering them equal opportunities. This is not a simple

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MasterClass in Science Education issue – girls are not under-represented in all STEM areas, and the factors that influence such a phenomenon as girls’ under-representation in physics, for example, are believed to include matters that are not under the control of school – such as parental attitudes, the availability of suitable role models in the family, and media representations – as well as the effects of teacher attitudes and expectations (Taber, 1991). There clearly are cultural norms at work. Women were not under-represented in engineering in the Soviet Union. In some Western European countries where secondary teachers are traditionally female, women are not under-represented on physical science degree courses due to the number who intend to become school physics or chemistry teachers (which means there is, or is not, an issue depending upon which part of the ‘pipeline’ is being examined – plenty of female undergraduates, even if few go on to research or industrial careers). The extent to which education systems should instigate initiatives to respond to questioned cultural norms is an interesting issue. For example, should girls be offered more support in mathematics (perhaps subject-specific mentoring) if it is shown that they are more likely to lack confidence and have low self-efficacy in the subject? To some extent then, STEM is an umbrella term for a coalition of different professional and academic groups that share some common ground, and that cooperate in raising issues of mutual interest: in particular seeking to support initiatives to encourage more students to consider STEM careers. There is also sometimes a suggestion that as science is part of STEM, then it may make sense to teach STEM, rather than discrete courses in science, mathematics, and technology. Perhaps teaching a school subject of STEM could do more to address the supply of STEM professionals and potential equity issues in these important subjects. This would allow teaching to be based around authentic STEM projects where mathematics and science are not learnt in the abstract, but rather put to use in solving problems and developing real products. As suggested above, there are likely to be both strengths and limitations in teaching STEM rather than science and other subjects. As is also suggested above, it may be sensible to consider a curriculum approach where STEM subjects are usually taught discretely (if with coordination) but sometimes brought together to complement teaching in the separate disciplines (Taber, 2018b). There have also been attempts to develop the idea of STEM by incorporating other subject areas, and another acronym that has become widely used is STEAM. Usually the A in STEAM refers to the arts, and STEAM advocates often put emphasis on creativity in teaching and learning. An alternative STEAM has A for ‘agriculture’ – an approach deriving from work in Japan, where traditionally science in primary school has a strong flavour of what might once have been termed ‘nature study’ (Sumida, 2018).

Final thoughts This chapter has suggested there is a range of different reasons we might want to teach science. The different drivers identified all have some claim on informing the curriculum, and

Critiquing the Science Curriculum they might each suggest different priorities for organising the curriculum and selecting curriculum content. The science teacher will have more input into decisions about the curriculum in some teaching contexts than others – with policies being made at national, school and departmental as well as at classroom level. The choices made by individual teachers are still important, and perhaps more so when those teachers are working in a highly prescribed curriculum context. Those choices will often be about balance and degree. To what extent should teaching emphasise science content against science process, or the learning of concepts against the learning of skills and development of attitudes. This is a matter not of selecting one pole or another, but of rather making choices about when to privilege and prioritise certain goals and objectives. If the range of topics to be taught is not prescribed, then to what extent should teaching cover a broad range of topics rather than engage students in depth with key ideas or topics? If topics are prescribed, how much flexibility is there to apportion classroom time to focus in more depth on some topics? A useful question is not whether students’ views should be considered, but when and how to best take their ideas into account. It is not sensible to ask if student choice is ever appropriate (it surely is), but it does makes sense to ask when and how much choice is advisable within a (in principle) common curriculum. Similarly, it may be valuable to ask when, and to what extent, teaching and learning should take place within disciplinary boundaries, and when it might be more sensible to look to interdisciplinary work. It is wise to question why things are done in particular ways. Sometimes there will be very good reasons, and changes may be unproductive. Sometimes there were very good reasons when decisions were first made, but these may no longer apply. Sometimes custom and practice have become established with limited rationale, and innovation could be beneficial. It is easy to get caught up in the busy routines of school teaching, and simply follow a pattern laid out (by our head of department, by our predecessor or by ourselves when we first had to set up our teaching), so it is useful to regularly review our own thinking about why we teach science – and to check that what we are doing makes good sense in terms of our fundamental educational values and purposes.

Suggested further reading Cerini, B., Murray, I., & Reiss, M. (2003). Student Review of the Science Curriculum: Major Findings. London: Planet Science/Institute of Education/Science Museum. Hansen, K.-H., & Olson, J. (1996). How teachers construe curriculum integration: The Science, Technology, Society (STS) movement as Bildung. Journal of Curriculum Studies, 28(6), 669–682. Stuckey, M., Hofstein, A., Mamlok-Naaman, R., & Eilks, I. (2013). The meaning of ‘relevance’ in science education and its implications for the science curriculum. Studies in Science Education, 49(1), 1–34.

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Reflecting the Nature of Scientific Knowledge in Science Education

Chapter outline The languages of science, teaching and social life Knowledge as a concept used in teaching An objectivist/externalist notion of knowledge The need for metaphysical commitments Reflecting the nature of scientific knowledge in teaching Good practice in representing scientific ideas Suggested further reading

The languages of science, teaching and social life Consider the following terms: learning teaching zzunderstanding zzknowledge zzmemory zzintelligence zzclever zzforgetting zzthinking zz zz

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MasterClass in Science Education I think most readers would agree that these terms: a)  are very relevant to education b)  are commonly used by teachers c)  are generally considered unproblematic

So we might consider these terms part of the professional lexicon or vocabulary of the teacher – terms used by teachers in professional discourse – when talking to other educational professionals about their work. By comparison, consider the following list of words: element compound zzhypothesis zzspecies zzmomentum zztheory zzphotosynthesis zzviscosity zz zz

These are words that are used in science as technical terms that relate to the concepts that have been developed in the sciences. These terms are used by scientists to have particular meanings, and because they are defined in particular ways (that are learnt when we are becoming scientists), they tend to support effective communication among scientists. There seems to be a parallel here between these two sets of terms from within two professional areas of activity (teaching, science). Laypeople may use science vocabulary words such as these. Sometimes they have learnt the scientific meanings (in science lessons perhaps) and use these terms in a technical sense. More commonly, words such as ‘momentum’, ‘energy’ and ‘theory’ (or many others such as ‘force’, ‘element’, ‘field’, ‘acid’ and ‘animal’ are also used in everyday discourse in ways that are somewhat different from how they are used in science (e.g. ‘nervous energy’), often in less tightly defined ways, and perhaps in ways that are more variable across speakers. That is not problematic in everyday conversational talk, which often has as much a social function as being a means to communicate critical information and ideas. Everyday talk invites a good deal of metaphor, hyperbole and other rhetorical devices that are often excluded from technical, formal, scientific communications. When scientists write scientific reports and refer to forces or species or elements they intend, and are understood to mean, these words as precise technical terms, and in such a context they should not use them in fluid, vague, impressionistic senses. This is not to criticise everyday ways of talking; the point is that different kinds of talk have different purposes, and so are appropriate in different contexts. People infer the meaning of ambiguous terms from the surrounding context. Consider the terms ‘cell’, ‘plant’ and ‘drugs

Reflecting the Nature of Scientific Knowledge in Science Education trial’: can you be confident what a term refers to without knowing the context in which it is used? Arguably, without such context the term has no referent. If the chemistry teacher tells a class they are going to learn about cells, that teacher likely means a completely different referent than would be the case had the biology teacher made the same statement. People can shift between registers in different contexts. Indeed, as a science teacher trying to buy electrochemical cells, it soon becomes clear that in a high street shop you will probably need to ask for ‘batteries’ even though you know that that technically is not what you want (i.e. the 9 V battery may indeed be a battery of cells, but the 1.5 V ‘battery’ is actually just a cell). If a friend is buying a toy as a present for their child and asks you how many batteries it will need, it would be inappropriate to respond ‘one’ when you know four cells are required to make up that battery. Being technically correct will not placate the frustrated child, and the friend (possibly ex-friend) may feel your pedantry is callous. Effective communication in everyday contexts may require deliberately being technically incorrect.

Talking in different registers Yet where the professional language of science has evolved to be tightly defined, this is not the case with the professional language of teaching, which draws upon terms commonly used in everyday discourse. Terms such as ‘thinking’, ‘knowing’ and ‘understanding’ are part of an everyday lexicon used to discuss mental activities – things that go on in minds. This ‘mental register’ (Taber, 2013d) is then drawn upon as if it were a technical vocabulary in education. Consider these examples: 1A.  The sample of sodium chloride was pure. 1B.  The breakfast orange juice was pure. 2A.  Beryllium is a group 2 element. 2B.  Water is an essential element for life. 3.   Frida was the most intelligent girl in her year group. 4.   The teacher had impressive knowledge of nanotechnology.

A scientist knows how the technical notion of ‘pure’ is being used in sentence 1A (what a pure substance means in ontological terms in chemistry), and probably has some idea of the extent to which purity could be determined (an epistemological issue), and how one might go about it (a matter of methodology). The scientist also knows that orange juice is a mixture, and so it does not make sense to understand sentence 1B to be referring to ‘pure’ in the chemical sense given the context of a complex mixture (see Chapter 12). Despite that, the scientist can switch from the technical register to the everyday meaning, and so appreciates in what sense orange juice is said to be pure (containing only substances directly from oranges, unadulterated by non-orange-sourced substances). Similarly, the pedantic science teacher knows that water is not an element in science (even if once considered so in ancient times), but has no problem in appreciating how the word is being used in sentence 2B.

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MasterClass in Science Education In these examples, the way the term is being used offers us context to appreciate whether the term is meant in a technical sense or not. What about sentence 3? We can imagine this could be something a teacher might say in the staffroom or at a parents’ evening. Perhaps it is meant as a technical claim. Perhaps intelligence has been operationally defined, and a suitable instrument (a test) identified, and the year group has been formally tested. Perhaps Frida’s score was higher than any other student’s, and indeed by a margin believed to be greater than any measurement error likely in using the test. Or, alternatively, perhaps the teacher is offering their personal opinion based on observation, experience and intuition. Either option is possible, and because the profession habitually uses mental register terms (e.g. intelligence) as if they were technical terms, we would need more information to know whether this was meant as a formal knowledge claim or a personal opinion.

Knowledge as a concept used in teaching Sentence 4 refers to knowledge, and – surely – we all know (sic) what knowledge is? Again, it is an everyday term, part of the mental register (the way we talk about mental phenomena and characteristics), that can be used as if it were a technical term in education. Indeed, knowledge does have status as a formal concept in philosophy (Goldman, 1995). One traditional notion of knowledge considers it as true, justified, belief. That is, someone has knowledge if they believe something, and have justification for believing it, and it is indeed true. So, by this criterion, there are three necessary conditions for something to be considered knowledge. We might ask if the teacher who stated that ‘Frida was the most intelligent girl in her year group’ had knowledge that Frida was the most intelligent girl in her year group. First, we would need to consider if this was a genuine belief. Perhaps the teacher was making a case for Frida being appointed head girl, or for being given another chance after committing an offence for which she could potentially be excluded from school, and the claim was made rhetorically despite the teacher actually thinking that both Belinda and Jasvinder were more intelligent than Frida. If that is the case, the teacher could not be said to know that Frida was the most intelligent girl in her year group. If persuaded on the issue of belief – we accept that the teacher genuinely believed that Frida was the most intelligent girl in her year group – we have to consider her grounds for this belief. If there had been the kind of testing suggested above, we might feel that there were good grounds (although alternatively we might potentially question the test, or its administration, or the marking of scripts etc.), and so the belief was justified. However, if there had been no such testing, and furthermore the teacher making the claim only had substantive experience of working with Frida’s tutor group, and so had little evidence for making a comparison with students in other forms in the cohort, then we would likely feel the belief – even

Reflecting the Nature of Scientific Knowledge in Science Education if strongly held – was not justified, and the teacher could not be said to know that Frida was the most intelligent girl in her year group. Finally, let us consider that there has been a suitable test (taken for the moment as a valid and reliable instrument to measure intelligence), which has been administered and marked correctly, and that Frida scored several standard deviations above any of her peers, so that we consider it true that Frida was indeed objectively the most intelligent girl in her year group. If the teacher believes that Frida was the most intelligent girl in her year group and is aware of this evidence, we might finally say she does know Frida was the most intelligent girl in her year group. But what if the test was confidential, and the results were reported only to the individual students, and the teacher was guessing the outcome? In this scenario, Frida was (objectively) the most intelligent girl in her year group, and the teacher believed that Frida was the most intelligent girl in her year group, but – by this standard for judging knowledge – the teacher did not know that Frida was the most intelligent girl in her year group as she had insufficient grounds for this claim. The teacher’s belief, although a true belief, was not sufficiently justified through a logical argument based on sound evidence. This kind of discussion may seem somewhat abstract, but it will prove to be of relevance to both our consideration of the nature of scientific knowledge in this chapter and the way we think about students’ ideas in science (see Chapter 6).

An objectivist/externalist notion of knowledge One feature of the traditional ‘true, justified, belief ’ notion of knowledge is that it assumes that someone can know what is true (otherwise no claims can meet all three conditions as no one is able to judge which claims are indeed true). Let us consider this in terms of some scientific ideas. Consider the following examples – you may find it useful to consider these examples in a critical way (e.g. do you consider they discuss knowledge; do these simple vignettes distort the cases discussed?).

Knowledge of phlogiston Joseph Priestley was an English scientist who made major discoveries in chemistry, as well as being a non-conformist who was hounded from his home-cum-laboratory (which was burnt down by a mob) because his personal religious and political convictions were found distasteful by many people in his community. Priestley believed in phlogiston: that is, he knew that what made some materials combustible was the presence of phlogiston within them. During combustion, the phlogiston was released. Priestley’s grounds for his commitment to phlogiston related to how this idea fitted with many observations and experimental outcomes he noted in his laboratory work.

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Not-so-special relativity? Galileo Galilei discussed a principle of relativity – using the example of someone travelling on a ship. If a ship out of sight of land was travelling by virtue of an ocean current such that to an observer on the ship the sea was completely still, the observer would not be able to tell the boat was moving. The ship might be moving relative to the seabed, but it was not moving in the frame of reference of the observable sea. In a similar way, the appearance of the sun moving through the sky showed relative movement that could be understood in different frames of reference. The appearance would be the same to an observer on the earth if the earth was still and the sun moving, as was generally considered at the time; or if the sun was still and the earth moved round it, as Galileo suspected; or, indeed, if the earth orbited the sun as the entire solar system moved at great speed through the galaxy, as current scientific thinking suggests. If two vehicles approach each other, each moving at 25 km s−1 as judged by taking the ground as the basis for a frame of reference, then within each vehicle travellers will observe the other vehicle moving towards them at a relative speed of 50 km s−1. Similarly, if two trains are leaving a station, side by side, moving on parallel tracks at the same speed, passengers sitting in a carriage in one train will seem to be stationary as observed by passengers in the other train. This seems a common-sense principle that should always apply. However, in a thought experiment, Albert Einstein undertook to ask what would happen if an observer could move alongside a beam of light. Electromagnetic radiation exists as an electric field which collapses to generate a magnetic field which then collapses to generate the electric field (etc.) – this dynamic process is part of the essence of electromagnetic radiation. But if an observer was alongside the beam, travelling at the same velocity, it should appear to be stationary. This can be considered to be an example of thinking using reductio ad absurdum – if the consequences that follow from one’s premises seem absurd, one should question the premises. Einstein’s intuition was that light had to be progressive to exist, and his response was to abandon Galilean relativity in the case of light. Einstein conjectured instead that light is always measured to travel at the (fixed, in an particular medium) speed of light relative to any observer, regardless of how fast the observer may be travelling according to some frame of reference. This led to the special theory of relativity – and a range of counter-intuitive deductions that could be used to test the theory (see Chapter 9).

Knowledge of jumping genes Barbara McClintock was a biologist who worked on generations of maize (corn) plants. Her close observations of the outcomes of various crosses of maize varieties led her to conclude that sometimes genes transposed (or ‘jumped’) to different places on the genome. Most of her colleagues knew this was not possible, and so believed she was mistaken – if not actually

Reflecting the Nature of Scientific Knowledge in Science Education a little crazy. It was only some years after McClintock had first argued for gene transposition that other scientists began to take the possibility seriously, and then slowly her heretical views became scientific orthodoxy (and McClintock became lauded as an insightful scientist who had made a major breakthrough).

Knowledge of a universal force Isaac Newton, among many achievements, came to the realisation that the orbits of cosmic bodies could be considered as a kind of falling. Newton imagined firing a cannonball from a high mountain with sufficient energy such that as it fell under gravity it maintained its height above sea level (as the curved earth fell away underneath it). The moon could be considered to be falling towards earth in a similar way, i.e. perpetually falling, but never actually getting closer. Newton proposed gravitation as a universal force that operated in the heavens just as it does at the earth’s surface. To appreciate the revolutionary nature of such an idea, one has to appreciate the long-standing tradition for considering the heavens to be perfect, unchanging and composed quite differently from the mundane world of earth. Many generations of schoolchildren have since been taught about universal gravitation as being one of the fundamental forces found in nature.

Knowledge of the illusion of gravity However, Albert Einstein offered a very different notion of gravity, as not being a force at all but rather as our experience of how mass distorts the geometry of space–time. Einstein’s theories of special and general relativity seemed counter-intuitive to most people when first suggested, but they led to a wide range of predictions that have since been tested. The modern perspective is that gravitational force is something of an illusion. This is similar to how the apparent centrifugal force that seems to cause people to slide across the back seat of a car going around a roundabout can be recognised as imaginary once we take the road as our frame of reference rather than the moving car. So we now know that Newton was wrong about gravity.

What counts as scientific knowledge? We could explore many more examples, but these are sufficient to consider what we mean by knowledge. Priestley had grounds for his commitment to the phlogiston notion (Thagard, 1992). Many of his peers, who were also convinced from their own work about the explanatory value of the phlogiston concept, would likely have considered Priestley had a true, justified, belief – that he knew that phlogiston was released when things burnt (Chang, 2012). Antoine Lavoisier, however, working with his wife Marie-Anne Paulze Lavoisier, became convinced that combustion was a reaction with a new chemical element – oxygen. From Lavoisier’s perspective (and a modern viewpoint), Priestley was wrong, and so his beliefs were not true.

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MasterClass in Science Education So, whether Priestley had knowledge – in terms of true, justified, belief – about the nature of combustion would have been judged differently by his contemporaries according to whether they were committed to the phlogiston theory or the revolutionary oxygen chemistry of Lavoisier. All might agree that Priestley was subject to arson, but whether his burning property released phlogiston during the episode would have been a matter of scientific opinion. It is often said that history is written by the victors but this is simplistic. Priestley moved to a new life in the United States (where he was influential, becoming a friend of President Thomas Jefferson), but Lavoisier was executed in revolutionary France for his role in the previous administration. At a time when science was not a recognised career, Lavoisier’s official job as a tax collector (part of a consortium of rich men who bought the right to collect taxes and made huge profits from this work) made him an enemy of the French revolution. His wife and coworker ensured that his work was circulated and remained influential despite his execution. Lavoisier is widely known as the father of modern chemistry, but Priestley (who isolated oxygen, but conceptualised it as ‘dephlogisticated air’) was once called the father of modern chemistry who never acknowledged his daughter (McLachlan, 1990). McClintock offers an interesting case for considering the nature of scientific knowledge. We might consider that McClintock ‘knew’ about gene transposition (i.e. she had a true, justified, belief) when many of her colleagues would have not considered that her ideas counted as knowledge – the scientific consensus in her field considered the ideas she had committed to as mistaken, and the scientific justifications to be flawed. Again, this example shows that if we need to know what is true to judge whether something is knowledge, then we need to take a kind of God’s-eye view (that is, we need to know for sure what is true ourselves) otherwise we have to accept that judgements of what counts as knowledge are relative to the person making that judgement. Science is said to seek ‘objective’ knowledge – knowledge that has a truth value that is independent of who is making the judgement – and relativism (considering that knowledge should be evaluated only within a specific context of some person or community at some historical time) is not sufficient in science. However, McClintock is interesting in another way. She was aware of how her work depended on intuitions, a process she labelled as ‘integration’. She made extensive detailed observations in the field and under her microscope, but she did not expect to solve scientific questions immediately. Rather she recognised the need for a period of subconscious incubation time whilst her brain ‘integrated’ information to develop insight into how nature worked. As a scientist, she had to then test and demonstrate her intuitive conclusions through formal scientific means (an argument grounded in scientific evidence). That is, in science the discovery of an idea may owe a great deal to creative imagination, but the justification must be based upon a clear argument from carefully analysed evidence. More than many other scientists, McClintock recognised the core importance of the creative aspect of scientific work that has to exist alongside the application of logic (Taber, 2011b).

Reflecting the Nature of Scientific Knowledge in Science Education Regarding Newton, if we accept the current scientific models as the best guide to the true nature of gravity, then we could judge that Newton did not have knowledge of gravity, because we now think his ideas were not the best way of conceptualising nature. By this standard, Newton’s ideas first became (inappropriately) judged as knowledge when they were widely accepted by scientists over many decades – before losing that status once Einstein’s alternative approach was accepted. As Newton’s ideas are still widely taught – perhaps in your classroom – this might suggest we are actively teaching something once considered knowledge but now discredited.

What kind of knowledge does science produce? Science is often presented in school as providing a kind of absolute knowledge: either burning releases phlogiston or it does not; either gravity is a force or it is an epiphenomenon due to the geometry of space-time; either genes jump about or they stay put. Science has no scope for ‘truths’ that are relative to time, place or particular groups of scientists. Yet if relative, or local, truths are of no interest in science, this invites the question of how we know what would be an eternal truth, given so many apparent truths of the past were later found not to be true after all. How can we know for sure what (if anything) has been settled for all time? The examples discussed suggest the particular criterion for knowledge as true, justified, belief may not be the best approach to understanding scientific knowledge – as it leads us to either claim we (unlike Priestley, Newton etc.) can recognise knowledge that will never be overturned or accept that nothing science produces can actually be assumed to be genuine knowledge. A more useful notion of knowledge might allow us to (metaphorically) sail between the Scylla of arrogance and the Charybdis of ignorance (see Figure 3.1).

Figure 3.1  Sailing the good ship science towards new knowledge.

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MasterClass in Science Education If we apply strictly the idea of knowledge as true, justified, belief, we surely have to accept that we are teaching false ideas as knowledge in school science, and – in the case of examples such as the Newtonian understanding of gravity – doing so knowingly (sic) and deliberately. This suggests that we either have to stop teaching such ideas or have to justify why it is acceptable to mislead students by teaching notions we now know are ‘not true’. It may help perhaps to frame the issue in terms of a direct question: Is it true that gravity is a force between masses? Someone accepting Newtonian physics would need to say ‘yes’, as perhaps would a student who had paid attention to what was being taught in school physics classes. Someone judging the matter in terms of the best current scientific understanding would surely need to respond ‘no’ for gravity is now ‘known’ (sic) to be essentially something rather different. Science is progressive. Science does not offer a body of knowledge which is absolute and eternal, but rather seeks to develop ever more detailed and insightful understandings of nature. So just as the phlogiston theory would once have counted as knowledge according to (then) contemporary science but has become discarded and is not considered sound knowledge today, it is likely that many of the things we teach today that are reasonable accounts of scientific knowledge will prove to be problematic in the light of future evidence, and so will become replaced and excluded from the canon of scientific knowledge in the future. Taking the true, justified, belief version of knowledge too seriously risks entering a vicious circle: to know if a claim should count as knowledge, we need to know if it is true: but that surely begs the question we are trying to answer. This is worth dwelling on because there is a widespread notion that science seeks true knowledge. Scientific knowledge is often held up to be absolute and definitive in a way that makes it trustworthy when other ways of knowing are fallible. Yet such an extreme account is not justified from a modern understanding of the nature of science (see Chapter 9). That is certainly not to suggest science should not be trusted – just that it cannot be considered infallible. Science is a way of doing things that is systematic and evidence based and (when done well) self-critical, which means it is much more reliable than guessing, or hoping to divine knowledge from patterns of tea leaves or the entrails of sacrificed animals, or just about any other approach that people have invented. But science still has limitations.

Historical obstacles to a modern understanding of scientific knowledge Current scientific thinking often betrays the remnants of earlier ideas upon which it was constructed (Bachelard, 1940/1968). The idea that science offers absolute knowledge – that science can prove things beyond doubt – perhaps derives in part from the mindset of the early modern scientists of the Enlightenment. Any person brings to their professional work a set of background beliefs derived from their culture (Geertz, 1973). A worldview offers a background of taken-for-granted commitments. These are ‘metaphysical’ in the sense that they are prior to examination of any empirical evidence.

Reflecting the Nature of Scientific Knowledge in Science Education Often these early, modern scientists were devoutly religious and adopted the premises of what is sometimes called ‘natural theology’. That is, these people were committed to a worldview that included beliefs such as: The world was created by a God who: a)  saw mankind as a special part of the creation; b)  created man in His [sic] own image; c)  wanted mankind to understand, to come to know, the world as God’s creation.

These ideas are still common among some communities, but are no longer principles generally accepted by scientists as underpinning scientific investigations. Regardless of how we might evaluate these ideas ourselves, we can appreciate how they influenced the epistemological assumptions of early, modern scientists who were strongly committed to them. The natural world was referred to as the ‘book of nature’ in which God’s works could be read alongside His Word in the book of Holy Scripture. The implication is that science can provide knowledge of nature because (i) nature is God’s creation, (ii) man is part of the creation, made in God’s own image, and (iii) it is God’s will that man should know Him through his works. An omnipotent God who wanted humans to understand His works would create humans with the faculties to do so. Given that set of metaphysical commitments, there is a strong expectation that applying the right methods will lead to true knowledge of the world. Some readers of this book may simply reject those particular commitments, in which case there is no reason to assume man has privileged access to the working of nature, and we might instead consider that there are limitations on the extent to which we can fully know the workings of the universe. Today science is an international and multicultural activity, and although some individual scientists would still adopt such a theistic worldview, many would not. Indeed, even many scientists who would consider themselves theists – believers in a creator God who sustains the universe – would not proceed to assume that such belief provided any kind of assurance of readily acquiring definitive knowledge through science. Regardless of personal beliefs, it is a generally accepted principle among scientists today that science should adopt what is known as ‘methodological materialism’. This does not mean that science rejects religion (some individual scientists do of course, just as others are religious – see Chapter 10), but rather that supernatural explanations have no place in science. Methodological materialism requires all scientific explanation to be grounded in ‘natural’ mechanisms that can be empirically investigated. The term ‘methodological materialism’ should not be confused with the similar term ‘metaphysical materialism’. A metaphysical materialist believes that all that exists is the natural world (from which emerges complex phenomena such as consciousness, society and love), whereas a methodological materialist may believe in such things as non-material souls or spirits, but must still exclude such considerations from scientific accounts. For example, a methodological materialist might believe that humans are conscious because that is a deliberate feature

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MasterClass in Science Education of God’s creation, but if exploring consciousness scientifically, would need to seek an explanation of how it arises in terms of concepts such as energy, neurones and natural selection. As scientific explanations do not call upon anything supernatural, it should not be possible to tell from a scientific account if the author of a scientific paper is religious, agnostic or indeed a vehement atheist. If the author is religious, then they may see their scientific explanation as complementary to a theological explanation: but the scientific explanation has to work in its own terms without reference to any supernatural considerations.

The need for metaphysical commitments To describe something as metaphysical implies it is not open to scientific investigation. Some ‘scientistic’ notions of science suggest that science is such a powerful knowledge-generating mechanism that there are no limits to its potential. (‘Scientism’ is a term that describes perspectives or worldviews that see science as potentially able to answer all meaningful or worthy questions, or at least the only source of knowledge worth taking seriously.) It may also be implied that because science is based on observations of the world, it can act as a starting point for enquiry that does not need to stand on prior assumptions (such as God created the world to be knowable to humans). However, a little thought suggests that in practice science is inevitably based upon some foundational assumptions that cannot be definitively demonstrated without somewhat begging questions (that is, without to some extent assuming what you think you are demonstrating). Science relies on an assumption that we can be considered as potentially independent observers of an objective physical universe. It seems pretty obvious to all of us that we live in a world that extends outside our own minds and bodies, and so exists independently of what we think of it. Still, philosophers have explored such questions as how we can be sure we are not dreaming, or that other people are not automatons, or how we can know we are not a disembodied brain being fed false virtual reality by a computer. (There was a tradition of undertaking thought experiments about this possibility before The Matrix film series adopted a similar scenario.) There are also serious philosophical positions that assume that reality is in some sense created by the mind of the observer, rather than being something external and independent. The point here is not whether such ideas seem fanciful, or unlikely or even silly; rather that it is actually difficult to logically exclude such possibilities. After all, the ideas that the earth is speeding through space, that all living things on earth have a common single-celled ancestor, that the whole universe was once smaller than a pinhead etc. seemed fanciful, or unlikely or silly to a lot of people at one time. Science also assumes this external world has some kind of underlying stability. Of course, there are changes, but at some underlying fundamental level this emerges from something fixed. For example, the constant changes in matter are assumed to be underpinned by a submicroscopic world of particles which themselves have permanence (see Chapter 12). It is assumed there are some underlying constants that are fixed and which lead to the world

Reflecting the Nature of Scientific Knowledge in Science Education having the structure it does. Views may change on what these fixed constants are – that is an empirical question for science – but there is a commitment to such constancy. Current scientific thinking puts the age of the earth as something like 4,500 million years, although some people have personal metaphysical commitments to an earth no more than 10,000 years old (see Chapter 10). That is something of a substantive discrepancy. The scientific evidence is considered extremely strong, but it does rely on radioactive dating, which assumes that radioisotopes have fixed half-lives. If a sample of an isotope shows it has a half-life of, say, 100 million years today, then its half-life is assumed to have always been 100 million years. This seems a very reasonable assumption, but it is an assumption. Some young earth creationists (including a very small number of scientists) argue that the half-life should not be considered fixed, and so the dating of the earth’s rocks is invalid. Very few professional scientists give such ideas credence, and it is difficult to see a theoretical mechanism that would allow such changes, but how could we know for certain that half-lives measured today were applicable a thousand years ago – before anyone had any notions of the atomic nucleus? Similarly, science assumes that some ideas are universal. For example, the Newtonian theory of gravity discussed above is called a ‘theory of universal gravitation’. It is assumed that the forces acting between bodies in distant galaxies follow the same patterns as those measured on earth. That seems reasonable and seems consistent with astronomical observations – but how can we be certain without the ability to be there making direct measurements? Measurements of red shift (showing that galaxies are receding from each other) are possible because science has measured spectral lines in the light from these galaxies. These lines are assumed characteristic of the elements from which the universe is made (although that has only been directly tested locally), and in light from distance galaxies the spectral lines are observed at different wavelengths. This is interpreted as shifts in those wavelengths due to the relative motion between the source and the observer. However, that assumes that the distant galaxies are made of matter just like the matter found here. If, say, hydrogen atoms in other parts of the universe had protons with slightly different charges than those in our galaxy, then the spectra would be different. That does not seem very feasible, but again this is falling back on assumptions, not direct evidence. Finally, science assumes that, despite the limitations and quirks of human psychology and cognition, the fundamental nature of the universe will be (to some degree) understandable to human beings. This might be considered arrogant and anthropocentric as few scientists would make the same claim of ants or dolphins or orang-utans. Scientists often also adopt values based on expectations about the universe and how it is best understood. Scientists often look for symmetrical or elegant patterns. It has been suggested the truth about nature is never ugly, but beauty and ugliness may not be entirely objective criteria. Scientists also have a rule of thumb (Ockham’s or Occam’s razor) that when there are multiple possible explanations (and it is always possible to think up alternative explanations), the simplest ones, with the least auxiliary explanations, are preferred. That is a reasonable heuristic, but sometimes the more complex, convoluted, complicated explanation may actually be a better reflection of reality.

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Reflecting the nature of scientific knowledge in teaching The examples discussed above show that it would be arrogant to assume scientists have ever provided an ultimate and final account of aspects of the natural world. Even when an idea becomes scientific consensus and stands for a century or even longer (as with Newton’s conception of gravity), it is possible that it might be abandoned or modified later. It is not only that some accepted science is likely to be supplanted, but that we cannot be sure which aspects might come to be questioned. This creates a challenge for teaching science. Most science teachers are enthusiasts for science, and rightly want students to both grasp the power of science as a means of generating useful knowledge and appreciate its superiority over guesswork, superstition, folklore etc. as a way of understanding the natural world. Yet there is a danger that such enthusiasm, and the need to simplify and offer clear teaching messages, can distort the nature of science to make scientific knowledge seem much more definitive and absolute than it is or could be. The science teacher is right to champion science, but without suggesting it can offer certain, absolute knowledge (see Figure 3.1). It is important to bear in mind that science has taken many wrong turnings and at various times adopted ideas which seemed well supported, but which then had to be discarded when new evidence was recognised. The strength of science is that it allows such self-correction as all scientific findings and ideas are considered to be, in principle, open to revision in the light of new evidence or ways of thinking about evidence. This is a key feature of the scientific attitude (a scientific value), and if we teach science to support the development of critical thinking and provide young people with the means to engage in civil society from a position of strength (see Chapter 2), it also needs to be a key message from an authentic science education. Some of the key features of a contemporary understanding of the nature of science are explored further in Chapter 9. Enquiry into practice: Student perceptions of scientific knowledge What do you imagine your students think about the ideas they meet in science? Do they appreciate that scientific knowledge is conjectural and often comprises models and theories that are not considered (by scientists) to be perfect accounts of how the world actually is? List some of the principles, laws, theories and (scientific) models you have taught in recent months. Invite a small number of students from some of your classes to talk to you (perhaps as small groups of three or four students that you know are comfortable working together). Ask them about ideas they have recently been taught:

How certain are these ideas? Are they considered precise accounts of nature? zzDo scientists think these ideas are now settled or are they still open to challenge? zz zz

Reflecting the Nature of Scientific Knowledge in Science Education

Representing science in teaching Most school students are not in a position to learn science by reading the primary research literature. They would not have the language skills to deal with the genre, and they would lack much of the specific technical vocabulary and required background knowledge to understand the arguments made. They would also have little basis for evaluating different papers on a topic, for example, where conflicting implications are drawn by different researchers. So, teaching science is not simply about presenting the science as represented in the literature. Clearly, scientific ideas need to be simplified considerably. They also have to be contextualised (whereas authors of journal papers can take a shared context for granted as they are writing for their peers). Examples need to be found that will be familiar and sensible for learners. And language needs to be used in ways that clearly communicate the essence of complex abstract ideas to young people with a limited background, and sometimes limited inherent interest, in the topic. So ideas need to be made relevant for the students in a particular class. There are a range of tools that teachers can call upon to represent the scientific ideas.

Teaching models Teachers use models of what they are trying to teach. Models may be of various kinds. Students tend to be most familiar with scale models, so a model is often seen as a much larger, or much smaller, version of something that is too small to be readily seen directly, or is much too large to bring to the classroom. So students may come across models of a plant cell or an electrical distribution system (a national grid). However, many models are not simply scaled-up or scaled-down versions of a structure. Physical models may need to be simplified and perhaps have some aspects exaggerated. So, for example, some anatomical models may be full scale (‘life-sized’) but present tissues as closely fitting together yet effectively discrete, ignoring connective tissues and how the circulatory system and nerves penetrate various organs. Often models are even more extreme abstractions, and reflect only some very limited aspects of what is being modelled. Some models may be very different in substance from what is being modelled. For example, electrical circuits may be modelled using water circuits – such as a central heating system with a ‘circuit’ of radiators. Head of water represents potential difference and water flow rate represents electrical current. In some ways, this is a good analogical model, but it may not be very obvious to students how the model represents an electrical circuit. Models of molecules and crystal structures may reinforce alternative conceptions (see Chapter 12), so some models of crystals show the ions as spheres with definite surfaces, with spaces between them, and linked by a material ‘bond’ such as a wooden stick or a wire or spring. It is easy for the teacher to appreciate that the model is meant to represent the relative arrangement of particles, and that there are not spaces or sticks (or springs) in the actual structure; but there is no inherent reason for a student to appreciate that this is so when shown a model and told it represents the structure of some crystal at the submicroscopic level. The author has been told by a student that as ‘everything is made of atoms’ then the bonds between atoms must themselves be made of atoms.

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Gestures and diagrams As well as material models that can be stored and brought into class when needed, the teacher uses other techniques to reflect and represent scientific ideas. Sometimes these devices may be formalised such as the hand positions used to illustrate Fleming’s left- and right-hand rules (i.e. to represent the relative directions of magnetic field direction, current and thrust/ motion in motors and generators). However, teachers will also draw upon the usual communicative repertoire used in everyday communication – this may include changing pacing and intonation, facial expressions and makeshift gestures (Jewitt et al., 2001). These devices complement the actual words used and rely on a largely tacit ‘grammar’ of emphasis – which may not always actually be shared with all the students in a class. Teachers also draw diagrams to illustrate specific points, and these may be highly schematic. Again, the assumption is that students appreciate how such representations are meant to be interpreted. This may often be justified, but it should not be taken for granted. Taking time to be explicit about how such representations are used both reinforces the message in a ‘multimodal’ way (with verbal language complementing the visuals) and avoids unintended alternative interpretations. Even what are considered common conventions (such as drawing longitudinal and transverse sections) need to be learnt, and not assumed. As one example, there is a common convention for showing an expanded (scaled-up) view of a section of a diagram (see Figure 3.2), but how many people will appreciate this spontaneously? It may seem obvious what is intended to some students, whilst others will need the convention explained to them.

Figure 3.2  Conventions used in representations may not be so obvious to the uninitiated.

Reflecting the Nature of Scientific Knowledge in Science Education

Figures of speech Teachers also use a good deal of figurative language in communicating technical ideas. This can be very powerful (Lakoff & Johnson, 1980). A key part of teaching science is making what is unfamiliar familiar (Taber, 2002), and a powerful way of doing that is showing how something unfamiliar is in some ways just like something much more familiar. This may be done explicitly with analogies and similes, or through metaphor. Analogies refer to a mapping of similarity in structure between two (or more) systems (Hesse, 1959). The electrical circuit can be compared with a central heating system, where the radiators may be considered to map onto resistors, the flow of water to map onto current, etc. A simile simply points out a similarity: activation energy is like a wall that can be of different heights. Metaphor is subtler – it offers an identity that is intended to be seen as figurative without that being explicit. The nucleus is [sic] the command centre of the cell. Nerves are [sic] the body’s telephone lines. These devices are potentially very useful in teaching. However, the teacher needs to bear in mind that although something unfamiliar can in some ways be just like something much more familiar, nonetheless it is never exactly the same (or it would be the familiar thing itself, and not unfamiliar). There are always differences. A circuit is in many ways different from a central heating system, activation energy is quite different, in some ways, from a wall and, in some ways, nerves are quite unlike telephone lines. This need not be a reason not to use such devices. Quite the opposite. What is important is that after introducing such a comparison, the teacher then emphasises the ways in which there is a similarity, and then explores differences. The familiar is a starting point, and staging post, in making what was unfamiliar become familiar. In what sense is activation energy like a wall? A wall may be made of bricks, and it may act as a boundary around a property – but that is not relevant to activation energy. A wall may act as a barrier preventing easy travel from one place to another (Mexico to Texas, say), and in a similar way, activation energy may act as a barrier to reactants reconfiguring into products (methane and oxygen into carbon dioxide and water, for example). Having established that the nervous system provides a kind of communication network, it is then important to consider ways in which the two systems are distinct. Of course, there are myriad ways in which nerves are not like telecommunication cables: material composition, mode of conduction, speed of transmission, potential for self-maintenance, metabolic requirements etc. So, the teacher needs to focus on where there could easily be inappropriate transfer of ideas, and where useful teaching points can be made in relation to the scientific ideas being presented. Might some students assume nerves are metal wires (or glass fibre)? Probably not (you never know), but it might be useful to reinforce the nature of nerves as human tissue. A telecommunication network has a symmetrical distribution pattern and does not use different lines for different types of information. Although there are central hubs (perhaps a bit like ganglia?), these support the periphery to allow different locations to communicate with

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MasterClass in Science Education each other – and observations and instructions can pass in either direction. So, there is a difference here which can allow a useful teaching point to be made about the nature and role of the central nervous system. The teacher should always be thinking about how their teaching could be interpreted. A common (if problematic) analogy that has often been used is that the atom is like a tiny solar system. Secondary-age students asked about this analogy often considered that the atomic system was bonded, like a solar system, by gravitational force rather than electromagnetic force (Taber, 2013f). It is unlikely that many – if any – of the students were ever taught that – but it is likely some incorrectly inferred it from an analogy intended to help them learn the science.

Narrative: Telling stories in science A particular tool that can be used in teaching is to provide a narrative that students can appreciate based on the various social resources they have available to interpret and make sense of what they are told. Telling stories is a central part of human cultures, and perhaps was essential in preliterate times. Narratives often offer a kind of truth. Good novels and films are about the human condition. They refer to characters, events and situations that are fictional, but at another level, the novel uses these as tools to say something profound about the nature of human experience, of love, of our fears, of our mortality. Myths are not meant to be assumed to have literal truth. If there was a historical Arthur (Ashe, 1987), he probably was not actually a king, did not have a round table, did not seek the Holy Grail etc., but the myth represents something about shared nationhood, identity, values etc. Narrative has a role in pedagogy. In Plato’s symposium he tells the tale, as retold by another, of a banquet and drinking party in which Socrates debates with others about the nature of erotic love. This provides the context to set out the detailed speeches of the different discussants. Even allowing for the oral traditions of the time, it seems that the symposium is a device for exploring the different philosophical positions, rather than the verbatim transcript it appears to be. Jesus told stories about (for example) the Samaritan who showed care and consideration for a fellow human from an estranged community when others ignored the man’s need; and the prodigal son who was treated to a feast on putting aside his promiscuous ways and returning to the family despite his brother’s feeling that it was he – who had stayed home and dutifully worked hard – who was more deserving. The listener is not meant to believe that Jesus referred to an actual real Samaritan or a genuine pair of contrasting brothers. The stories are meant to convey a deeper truth (e.g. the people who choose to care about us and be considerate towards us, are our real neighbours). Telling stories like this is ingrained in our culture – so it is not surprising it is found in science teaching as elsewhere. How many schoolchildren think Newton was hit on the head by a falling apple? As far as I am aware, there is no source for that, and it is not supported by Newton’s own account. Newton reported that he had an insight when he saw an apple fall

Reflecting the Nature of Scientific Knowledge in Science Education from a tree. It is unlikely he would have a clear view of such an apple if it landed on his head (unless he was lying down under the tree looking straight up at it, which should have given time for evasive action), and it seems likely he would have mentioned this detail if he had actually been hit by the falling apple. That said, the narrative is somehow stronger if the apple hit his head, and this version seems to have been repeatedly retold. I still recall one anecdote I was told during a school chemistry lesson (i.e. about forty years ago) about the failure of Napoleon’s army in Russia. As is well known, the Napoleonic forces had to face the harsh Russian winter after a difficult campaign where the Russians had employed a strategy the French had not anticipated. The Russians continuously withdrew in front of the advancing French and burnt the potential spoils of victory (buildings that could be used for shelter, crops that might be taken as food) so that the invading army had to be resupplied by an increasingly stretched supply line. The particular story I remember from school chemistry is that the French army had tin buttons on their uniforms, and the Russian winter was so cold that these crumbled away, so that coats blew open and trousers had to be held up. This did not help the ability to fight, or the army’s morale. Now although this is a well-known story, it appears to be apocryphal with no historical basis. Despite that, the story helped me learn that tin has a number of allotropic forms, and that the one that is stable in the cold is crumbly unlike tin familiar at higher temperatures. The narrative, the image of Napoleon’s men fighting with one hand whilst the other hand held their trousers up, worked as a good vehicle for communicating some science, even though it was a fiction. Does it matter that in order for me to learn something about chemistry, I was told an amusing story which was not true? I wonder what a history teacher would think about taking such liberties with their academic area?

Personification: Object as sentient agent A particular narrative device that is widely used in human society, including in science teaching, is personification. Young children talk about the wind or the moon as though they are sentient agents. The wind decides when to blow – the moon follows the child down the street (a reasonable deduction from observations if you do not understand parallax). Narratives that are about human, or human-like, characters appeal to us, and are easily interpreted; thus, all those children’s stories with mice and rabbits and the like that are presented as people in a different form. I seem to recall getting the idea as a child that birds built nests to be their homes – I think I had the notion that the nest was more than a place to incubate eggs, but rather somewhere for the bird family to live together. I doubt I was ever told that, but rather automatically interpreted whatever I was taught about nests in terms of more familiar human needs and behaviour. Science teachers often personify non-living objects to support communication. For example, in the teacher explaining what happens at a junction in a circuit, it may be said that the electron has to decide which path to take. It is even suggested that asking students to write an

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MasterClass in Science Education imaginative story of an electron travelling around a circuit can be a creative way to get them to apply their classroom learning, which is likely to be more readily recalled (Taber, de Trafford & Quail, 2006). Perhaps the electron feels under pressure in the battery, notices it is part of a busy crowd of electrons, carefully moves through the spaces in the lattice and so forth. Such an approach can be very powerful; indeed, so powerful that students may be seduced by such narratives. (Seduced in a metaphorical sense, of course!) Seventeen-year-old chemistry students who had been successful in school science and were studying chemistry at an advanced level were found to commonly use language such as the ‘the atom wants to’, ‘the atom needs to’ or ‘the atom is happy now’ in explaining chemistry (Taber & Watts, 1996). Students used these tropes as if they were giving technical explanations. Some acknowledged that atoms did not really have feelings and needs, but still habitually used such expressions. Using personified accounts that explain what electrons or atoms (etc.) do in relation to familiar human social life (the atom gives an electron to another; the atoms share electrons) seems to be effective in helping learners become familiar with the unfamiliar world of submicroscopic particles. Yet, it also seems to stand in the way of learning of the scientific accounts.

Avoiding strong anthropomorphism A distinction has been made between: (a) weak anthropomorphism, where narratives treat entities as if they have human feelings and perceptions and abilities, as part of the initial stage of familiarisation with scientific objects; (b) strong anthropomorphism, where students adopt and come to habitually use such ideas as if they were scientific accounts.

So, for example, even if students have been taught that ionic bonding can be understood as the electrical interactions between the lattice of ions, with each ion surrounded by and attracted to a number of counterions, they are still likely to report that ionic bonding is an interaction between two specific ions based upon a shared history of a (likely non-existent in scientific terms) event: an electron being transferred between them (Taber, Tsaparlis & Nakiboğlu, 2012). Two human beings may share a ‘bond’ (that is, an emotional bond in this case) due to some history of a past mutual experience fondly remembered – and students seem to readily transfer this kind of thinking to inanimate submicroscopic particles.

Good practice in representing scientific ideas In all of these examples – teaching models, figures of speech, narratives and so forth – there is an affordance in making abstract and difficult ideas seem accessible to learners. However, students may readily stick at this point. To move them on to scientific accounts, the teacher needs to be quick to explore critically the limits of such a familiarisation device. This should

Reflecting the Nature of Scientific Knowledge in Science Education be done soon after the introduction and use of the device, so before the student has an opportunity to become fixated on it, and then starts to use it habitually. For example, whilst ‘weak’ anthropomorphism is a useful way of making the unfamiliar familiar, the teacher needs to carefully move the students beyond anthropomorphic language once students are sufficiently confident in the newly familiar scientific ideas. An analogy suggested here is to the training wheels added to a bicycle for someone learning to use a bike for the first time. A bicycle is inherently unstable – it falls over unless the rider has learnt certain skills to keep it balanced. The training wheels prevent the bike from toppling when the rider is not balancing the machine correctly. Their purpose is to provide initial support – but a rider who comes to rely on the training wheels may wish to keep them on their bike permanently, and so never develop the skills of using a bicycle. Some science classrooms are full of children who keep their training wheels on (and, of course, there are also ways in which the habitual use of what were intended as familiarisation devices is not the same as keeping training wheels on a cycle), but do not think that is anything out of the ordinary, as indeed their peers are doing the same. If all your friends think that a molecule is held together because the atoms share electrons, then you may have no reason to question that idea yourself. Enquiry into practice: Moving beyond familiarisation What do you imagine your students think about the simplifications, teaching models, metaphors, analogies and similes you use in teaching science? Do they appreciate these are tools to help them? List some of the simplifications, teaching models, metaphors, analogies and similes you have used in teaching science topics in recent months. Consider, in particular: a) the ways in which these tools do represent the scientific idea being taught; b) the ways in which these tools do not reflect and represent the scientific ideas they are intended to help students learn about.

Invite a small number of students from some of your classes to talk to you (perhaps as small groups of three or four students that you know are comfortable working together). Ask them about some examples of these teaching representations: zz zz zz

Do they appreciate these are representations, not the scientific knowledge? Can they distinguish teaching models from scientific accounts? Do they understand how analogies, metaphors and similes link familiar examples with the scientific concepts?

If you identify problematic examples (where students take models, simplifications, figures of speech, and the like for the scientific accounts they are being asked to learn), then you might consider some follow-up work when you next use these devices in introducing a class to scientific ideas. This can include building into your planning how you will shift students beyond these initial ways of understanding, monitoring your own teaching to observe how readily you manage these shifts (and whether your language betrays regression to the habitual non-scientific ways of talking), and brief interviews with a purposefully chosen (e.g. not just the high achievers) sample of students after each lesson in a sequence to make sure you are shifting their thinking beyond the initial limited understanding offered by the familiarisation device.

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MasterClass in Science Education A particular key here is in monitoring and modelling the use of language. It is not appropriate to be overcritical of students when they use metaphorical or anthropomorphic language such as that employed in first introducing new ideas. However, over time, the teacher needs to model the more technical language of science. This means the teacher needs to be alert to how students talk about the scientific ideas, and to make judgements about when students will be comfortable moving beyond the temporary support of less technical expressions. Students’ informal language should not be explicitly criticised (at least not initially  – perhaps this may need to be reviewed if it is proving difficult to extinguish over extended periods), but rather the teacher should reflect back more technically acceptable versions of what students say, in order to model the target language of science.

Final thoughts Perhaps one of the greatest challenges facing the science teacher is to convey to students that science offers a robust approach to developing trustworthy knowledge of the natural world, yet that knowledge should never be considered as absolute and certain. Scientific knowledge is theoretical and conjectural, and so strictly provisional even when it is based on extensive empirical evidence. In this chapter, some historical vignettes have been used to illustrate this point, and such an approach may also be useful in teaching. Scientific knowledge largely comprises models, theories and laws that offer imperfect – but often very useful – accounts of the complexity of nature. Bearing that in mind may be useful when one is considering student understanding of science. If science involves developing well-motivated, often simplified, accounts of aspects of nature that are comprehensible to scientists (necessarily limited by the affordances of human cognition), then science teaching often relies upon teachers presenting narratives that imperfectly model scientific ideas in ways that will make sense to students. As scientific knowledge is provisional, there is always scope to acquire further data, and to explore alternative conceptualisations that may allow scientific understanding to progress: to support the construction of more sophisticated knowledge. Similarly, as teachers, sometimes we may have to settle for imperfect metaphors, models and representations when first introducing abstract and complex ideas if we want students to make any sense of them. However, as with science itself, an initial conceptualisation may offer a level of familiarity which can be used as a starting point for developing more sophisticated ideas. It has been noted that students’ own alternative conceptions of scientific topics sometimes seem to reflect historical scientific models that science has discarded (Piaget & Garcia, 1989). The history of science should remind us that what we are teaching should not be considered as absolutely definitive, and that the process of developing sophisticated scientific ideas may involve intermediate stages that, although limited, represent genuine progress in thinking scientifically.

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Suggested further reading Gilbert, J. K. (1998). Explaining with models. In R. Mary (Ed.), ASE Guide to Secondary Science Education (pp. 159–166). London: Stanley Thornes. Styles, B. (2003). Analogy – constructive or confusing? A students’ perspective. School Science Review, 85(310), 107–116. Taber, K. S. (2017). Models and modelling in science and science education. In K. S. Taber & B. Akpan (Eds.), Science Education: An International Course Companion (pp. 263–278). Rotterdam: Sense Publishers.

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Subject Knowledge and Continuing Professional Development

Chapter outline What do we mean by teaching? Subject knowledge and pedagogic knowledge Knowledge of students Suggested further reading

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Teacher subject knowledge is critical to effective student learning. At a fairly basic level, the subject teacher’s job is to teach students their subject. If the teacher’s knowledge of the subject matter is incomplete, then they will not be able to teach something they do not know about. If the teacher’s subject knowledge is flawed, then what they teach will be flawed, which will impact on what students learn (i.e. the learning is likely to be flawed). Even though teaching is not a simple matter of passing on knowledge, it seems clear that a teacher with poor subject knowledge is not well placed to do a good job.

What do we mean by teaching? Even in contexts where the lecture may still have credence as a regular teaching method (universities working with highly able and motivated students selected for having mastered background knowledge and having demonstrated themselves capable of academic learning), a good lecturer does a lot more than regurgitate information to students. Rather, the lecturer employs

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MasterClass in Science Education various pedagogic devices and strategies (if sometimes without these being explicit). More generally, good teaching is expected to be more than just effective retelling of the material.

Facilitators of student learning Sometimes teachers are encouraged to see themselves less as lecturers than as facilitators of student learning. Whilst a term such as ‘facilitating learning’ has rather dropped out of fashion, and in any case was seen by some teachers as just jargon (a fancy alternative to teaching), it has the useful property of focusing on the learners, shifting the emphasis from what the teacher does (teaching) to what we want the student to do (learning). If teaching is understood to be facilitating learning, then no amount of lecturing counts as teaching unless and until some learning actually results. This raises the question of whether a teacher-as-facilitator could sometimes teach effectively without mastering the knowledge that is to be learnt. So consider that the class has been learning about the nature and main types of diseases that humans suffer from. The teacher may set a research task to select and find out about a specific disease in some detail, and in particular relate it to the general principles and models taught in class, and then ask students to prepare a means of sharing their example with the class. One way for a teacher to approach such a task is to nominate five or six, or even ten to twelve, diseases that the teacher knows about. Another approach would be to give students a free choice, aware that in some cases they may select a rare disease that interests them because of some motivating personal relevance (a family member has been a sufferer, or perhaps a historical or literary character that interests them, or a celebrity they know of such as a sports star). The potential value of offering students choice of topics and foci, when this fits with our teaching objectives, is discussed in Chapter 2. In one approach, the teacher limits the scope to their own knowledge base and is better able to spot any erroneous information; in the other approach, students can follow their own interests, and a wider range of examples is likely to be considered. That latter approach risks students presenting false information in class, without it being corrected. That is far from ideal, but we may be prepared to tolerate that if we considered that our general goals for the class (see Chapter 2) were better supported through offering more choice. A teacher may even consider that their knowledge of the subject is improved by offering more open-ended activities where students in effect act as research assistants and teach the teacher about lesser-known diseases. Whether a teacher feels confident in setting such activities will depend in part upon their attitude to the nature of teaching and the role of the teacher as the main focus of knowledge in the classroom. We all need to consider to what extent is it reasonable, or even helpful, for students to expect the teacher to know everything about their subject. It is not being suggested that the classroom needs to be a place of laissez-faire activity of a community of learners where the teacher is just one among many; that is likely to be as unhelpful as an assumption that the teacher should know all and be infallible.

Subject Knowledge and Continuing Professional Development However, good teachers certainly need to be aware of the limits of their knowledge, and to be open to new learning.

Conceptions of teaching How we judge teaching (and decide what is ‘good teaching’) is likely to depend upon our notion of what teaching actually is. One possible understanding of teaching is simply that it is what teachers do in their classes. An observer approaching classrooms as a school inspector is likely to already have some pre-established ideas of what teaching should be and consider such a definition inappropriate, but someone who approached the classroom as an ethnographer – without preconceived ideas of what teachers do or should do – would be open to observing what actually occurs and trying to make sense of the culture of teaching as understood and experienced by the teachers themselves. This reflects a key distinction in undertaking educational research: one (positivistic) approach which adopts in advance an analytical framework for making sense of, and perhaps for quantifying and evaluating, what is researched; the other (interpretative) approach as an attempt to understand the research focus in terms of the beliefs, perceptions and experiences of participants so as to develop a qualitative account without necessarily seeking to judge what is found (Taber, 2013a). An alternative notion might be that teaching is what teachers, qua teachers, do – what teachers do professionally as part of their work. This alternative would include lesson preparation, marking, attending meetings with parents, professional development and so forth. This definition extends the notion of teaching in time and space well beyond the actual lesson taking place in the classroom. That definition would be challenging to any researcher looking to produce an account of teaching, as data collection would require much more than observing classrooms. Perhaps a teacher reflects upon their lessons and evaluates them on the commute home from school. Perhaps a teacher has their best lesson ideas in the bath. Perhaps much of the thinking that leads to solving professional problems actually occurs during sleeping. Alternatively, we might restrict our understanding of teaching to those actions carried out by teachers that actually bring about intended learning. By that definition not everything that all teachers do in their classrooms would be teaching, but at least some lesson preparation and marking would be part of the teaching process – as indeed might time spent in a case conference discussing why a particular student is disengaged and underachieving, at least if that meeting contributed to bringing about a change that contributed to the student learning more. An obvious challenge with this definition of teaching is that to produce an account of any teaching we have to know when learning has taken place, and what actions on the part of the teacher had an effect to bring about that learning. (By comparison, a definition that teaching is simply whatever a teacher does in the classroom allows us to produce an account of ‘teaching’ without needing to evaluate the consequences of the observed actions.) One more notion of teaching might be based on a teacher’s actions that are intended to bring about learning. This does not require learning to occur, but excludes any activity that

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MasterClass in Science Education is not designed – directly or indirectly – to impact learning. This may not just exclude ‘slacking’: in today’s schools sadly teachers may be spending a lot of time meeting secondary objectives that they may not consider to be contributing in any direct way to student learning. As one example, school leadership teams may regularly check that students’ books are marked because this is seen as an indicator of teaching. Now, I am not suggesting that providing students with written feedback cannot sometimes make a significant contribution to learning. Yet in many classes it is likely that teachers should sensibly focus on providing targeted feedback on certain pieces of written work. If teachers are deciding what to write in students’ books on the basis instead of an expectation of how often comments should appear because of (well-meaning, but misjudged) criteria used to inspect books internally, in turn based on giving a certain kind of impression to parents (who are mostly not educational professionals) or visiting inspectors (who are often expected to evaluate schools on unrealistically short visits), then much of this time and effort is not – by this definition – teaching. Deciding exactly what we think teaching is, what counts as teaching (see Figure 4.1), would be especially important before setting out on a research project which focused on teaching. Before we can engage in decisions about an appropriate strategy for carrying out research into teaching (a methodological issue), we would need to think about the kind of knowledge about teaching it is feasible to develop (an epistemological issue), which in turn depends on our conceptualisation of the nature of teaching (an ontological issue). There is a logic to developing any research design (Taber, 2013a). As a practical example, consider a study designed to explore why a particular teacher considered to be highly effective was so successful. We might include interviews with the teacher and observations of them at work. If our definition of teaching included work done in preparation for lessons, as well as work done in the lessons themselves, then that might have consequences for what we might want to ask the teacher about, and even what we might want to observe. Perhaps, on such a definition of teaching, the process might include the work the teacher does to maintain and develop their own subject knowledge. These aspects of the professional work of teachers could easily be ignored, or at least underplayed, if teaching was defined purely in terms of the teacher directly interacting with learners. On such an exclusive

Figure 4.1  Researching or evaluating teaching requires us to define exactly what we think teaching actually is.

Subject Knowledge and Continuing Professional Development definition, the lecturer recording a video presentation to be viewed later by students working at distance and accessing materials via the Web is not teaching at all. For the purposes of the rest of this chapter, I will use a definition of teaching science as a process intended to bring about learning of science in students. A core part of this process in school science teaching is the direct interaction between teacher and students (as a class, smaller group or individually) within timetabled periods of science lessons. However, these interactions are supported by other activities carried out by the teacher that are intended to facilitate learning. I suggest that effective subject teaching is informed by lesson planning that is itself in turn supported by other actions and processes involving subject knowledge, and then relating that to educational theory.

Subject knowledge and pedagogic knowledge An important idea in considering teacher expertise is that the effective school or college science teacher needs to draw upon a diverse knowledge base. Obviously, knowledge of the subject to be taught is important – but sadly it is not unusual to find subject experts who are very weak at communicating key ideas in their subject area despite having a very strong subject knowledge. So subject knowledge is necessary, but not sufficient, for effective teaching. We can consider some of the other kinds of knowledge that are important. The teacher also needs to know about such matters as the curriculum, and the institutional context. Having a good knowledge of, say, biology is fine, but unless the teacher knows that particular biology content is prescribed in the curriculum, classes may not be focused on the things students are expected to learn. There is an issue related to teacher professionalism here. Who should decide what teachers teach? Or, perhaps more subtly, to what extent should the individual professional teacher decide on the material to be covered – that a certain topic is best dealt with in a summary fashion for some groups – or what material, strictly beyond the prescribed curriculum, it would be beneficial for certain classes to meet? This is not a straightforward matter. Teachers are often in the best position to understand the interests and capabilities of their classes. Yet teachers may also have personal enthusiasms or biases that can influence their choice of content. If a teacher had undertaken doctoral research on echinoderms, then drawing examples from this group can enrich teaching, and this may give students a sense of the excitement of doing science: but extensive teaching about such a specific focus could, when taken too far, unbalance a course and start to bore learners. In the United States, there is much evidence that many teachers charged with teaching biology chose to exclude, limit, downplay or distort one of the key themes in the subject – evolution by natural selection (a topic considered in more detail in Chapter 11). In the judgement of some commentators, that is not exercising teacher professional responsibility, but is actually negating the responsibility of a professional teacher.

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MasterClass in Science Education In terms of local context, the effective science teacher needs to understand the timetable, the available laboratory facilities and equipment, the level of technician support and how it is accessed, policies on organising classes (e.g. are they set by ability?) and so forth. These might be considered largely ‘practical’ matters that any intelligent person would soon master. However, another area of a teacher’s expertise is pedagogy. A good teacher knows about the business of facilitating learning – they have acquired pedagogic strategies and skills. They have knowledge of the nature of learning and knowledge of teaching approaches. They understand methodologies of teaching. Enquiry into practice: Teaching to the test? In some contexts, such as in English schools, the curriculum has become highly prescribed, and has become complemented by examination specifications that set out precisely what is to be taught, sometimes complemented by textbooks written to match the specifications as precisely as possible. Teaching a subject can be understood as teaching precisely what is specified – sometimes to the level of the examples used and phrasing to be employed. Teachers are now often given detailed feedback on how examination questions were marked. Science teachers reaching the end of their teaching career in that same national setting will recall having taught under very different circumstances: being given much more responsibility for choosing from a range of quite different examination options, and selecting course material, and determining the level at which a topic should be taught. To what extent do teachers in your department (or those you know in other institutions) feel they do, and should, have choice in interpreting the curriculum, and making decisions for the treatment for different groups of students? What would you and colleagues do if you thought the specified science was flawed? Would you teach something you considered incorrect if examination marks were at stake? For example, an official examination board has in the past specified that students will be assessed on the idea that the ionic bond forms by an electron being transferred from a metal atom to a non-metal atom. This is nonsense (Taber, 1994), but is widely reflected in school textbooks. It is also a source of serious misconceptions that are problematic if students move on to advanced study of chemistry. Should a teacher teach the material specified even when they consider it is scientifically invalid and pedagogically harmful? How do you and your colleagues justify your position here in terms of the nature of teaching and the professional responsibilities of teachers?

Pedagogic knowledge This domain of pedagogic knowledge is quite extensive. Here are some specific concepts that teachers have traditionally been expected to know about: Piagetian stage theory, e.g. young children lack the patterns of thought available to teenagers and adults; zzBloom’s taxonomy of educational objectives in the cognitive domain, e.g. evaluation is a higher-level skill than application of learnt principles, which is a higher-level skill than recall of facts; zz

Subject Knowledge and Continuing Professional Development Vygotskian theory, e.g. that learners can be moved towards competency through carefully structured and progressively faded scaffolding; zzthe spiral curriculum, e.g. that primary students can learn about any topic (forces or atoms or genetics) in some ‘intellectually honest’ manner, and this can be built upon by revisiting the topic in a more complex and abstract way periodically through their schooling; zzMaslow’s hierarchy of educational needs, e.g. that a student who is tired and scared cannot engage in learning effectively until more basic needs (rest, security) are met; zzflipped learning, e.g. that classroom time may sometimes be used more effectively for active learning if students can undertake prior study to familiarise themselves with basic content; zzcontext-based learning, e.g. that students may be more engaged when core concepts and principles are introduced through contexts that they see as familiar, relevant and interesting; zzInitiation–response–evaluation (IRE) patterns in classroom teaching, i.e. that much classroom talk engaged in by the teacher with students is based on the pattern that the teacher asks a question (to which they usually already know the answer: ‘why do we need two different metals to make an electrochemical cell?’; ‘what is the unit of pressure?’, ‘why don’t very small organisms need circulatory systems?’), a student responds and then the teacher offers feedback evaluating the student response; zzwait time: the time between posing a question and accepting a response, which needs to be long enough to allow students time to carefully think through a response. zz

There are of course a great many other examples that could be listed. Pedagogic knowledge of this kind is generally applicable. Most such principles, concepts, models and theories are just as applicable to teaching modern languages, humanities, social sciences and STEM subjects such as the sciences. This domain consists of a general ‘toolbox’ to support all teachers. However, the effective application of these ideas needs them to be worked through in the context of particular teaching content. So, as one example, a teacher will want to ask students to engage in higher-level cognitive skills, and so will wish to plan lesson activities so they engage students in critique, analysis, synthesis and evaluation – as well as in recalling information (or acquiring information to recall), demonstrating understanding of ideas and applying them. The principle is widely applicable, but the process of application in a lesson on the causes of the industrial revolution, or on perceptions of race in society, or on electromagnetic induction, photosynthesis or the transition metals, will differ. In effect, the teacher has to have a good understanding of both the pedagogic principles and the subject matter if they are to apply the principles effectively in subject teaching.

Pedagogic content knowledge This has led to the notion of pedagogic content knowledge, sometimes abbreviated as PCK (Kind, 2009). PCK is neither subject knowledge nor basic pedagogic knowledge, but rather a synthetic form of knowledge (thus requiring higher-level cognitive skills from the teacher!) that builds upon both. Someone with good subject knowledge but limited knowledge of educational ideas will not be able to develop effective PCK (something that

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MasterClass in Science Education university students have sometimes noted in lectures by some world-famous academics). Equally, a highly skilled teacher asked to teach a topic where their own subject knowledge is limited is unable to effectively apply their strong pedagogic skills to form specialist PCK. They may give an entertaining and engaging talk, but that does not mean they have been able to identify suitable core teaching objectives for the topic, sensible sequencing, effective links to prior learning, helpful analogies, metaphors and models, telling examples etc., so learner engagement may not lead to effective learning of the key ideas of the topic. This links back to the argument about whether someone with a degree in, for example, electrical engineering, genetics or geology should be expected to teach school science across the full science curriculum (see Chapter 1). It is sometimes said that a good teacher can teach anything. Perhaps, although perhaps not, if they have no interest in the subject, and certainly not if they are not given sufficient opportunities to learn about it! PCK then is different to, but built upon, knowledge of the subject to be taught. PCK is rather knowledge of such matters as: how to best sequence teaching of a specific topic to best support learning; which aspects of a particular topic students (e.g. of a certain age) will find more challenging; zzhow to divide content into manageable chunks (‘learning quanta’) for particular groups of students (the topic of Chapter 5); zzwhich contexts, examples and applications are familiar and engaging for learners; zzwhat effective teaching resources are available for the topic which may be suitable for particular groups of students. zz zz

In science subjects in particular, PCK includes: knowledge of students’ common alternative conceptions (‘misconceptions’) (see Chapter 6); suitable demonstrations and practical activities, and how to ensure they support minds-on learning (see Chapter 14).

zz zz

Although initial teacher preparation can certainly support new teachers in acquiring PCK, as a synthetic area of knowledge, drawing upon subject knowledge and pedagogic knowledge, it requires the application of pedagogic knowledge within different content domains. Moreover, development of PCK requires cycles of teaching – that is, cycles of planning, classroom experience and evaluation of teaching that incorporates assessment of student learning. Teaching, done well, is a form of enquiry (see Chapter 1). The nature of the process is cyclic both because teaching is a complex activity and because understanding how different ‘variables’ (sequencing, examples etc.) feed into effective classroom teaching is difficult to achieve (because so many factors are interacting: classroom teaching is never a well-controlled experiment), but also because every class is different and teachers need to understand and be able to respond to that variation.

Subject Knowledge and Continuing Professional Development Teaching experience therefore supports the development of PCK – however, there is a more complex dynamic than that. Applying educational ideas in teaching helps develop understanding of that basic pedagogic knowledge. Developing PCK involves exploring subject knowledge in the context of educational thinking, and so can deepen understanding of the science itself. Indeed, there is a widely used teacher’s aphorism that ‘you only really understand something when you come to teach it’ or ‘when you come to explain it to someone else’ (see also Chapter 15). Most teachers come to recognise this, and often come to appreciate limitations or even errors in their own knowledge of some topics within their nominal subject expertise once they have to find ways to explain and illustrate it, and then to respond to learners’ questions as they try to make sense of the teaching. So educational and scientific knowledge feeds PCK, and in doing so can develop understanding of pedagogy and the science (see Figure 4.2). Even if science teachers do not continue to formally study science, it is commonly considered necessary to update knowledge through reading science news (perhaps through such media as New Scientist and Scientific American, if not more serious literature), popular science books, science documentaries and radio podcasts and the like. Many major science organisations have social media feeds highlighting new material on the Web. Such reading and listening seldom suggests teachers need to change their fundamental understanding of core science concepts, but new research can reflect subtle shifts in how some scientific ideas are being understood, and certainly provides sources of contemporary examples and applications that can be used to freshen up teaching and link with material students may be aware of from their own interactions with media.

Figure 4.2  Pedagogic content knowledge (PCK) is developed over time when teaching is treated as an enquiry activity.

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Knowledge of students As well as developing professional knowledge for teaching derived from understanding of science, of educational principles and of the institutional context, another very important factor is the learner or class. Every learner is somewhat unique. Every class has its own particular dynamic that emerges from the interactions within the group, and between the students and the teacher. Teaching (when it is seen as action aimed at facilitating learning, rather than simply presenting content) needs to be informed by knowing about students’ interests, aspirations, strengths and quirks. Of particular importance in teaching a highly conceptual subject such as a science, teachers need to know about students’ own knowledge and understanding of the subject matter before teaching a topic (i.e. to undertake diagnostic assessment), and as teaching proceeds (i.e. to undertake formative assessment). This is particularly important as a great deal of research suggests that student knowledge of science topics does not lie somewhere on a linear dimension from complete ignorance to expertise (see Figures 1.4 and 1.5). Rather, students often have alternative conceptions that are consistent with target knowledge to different degrees (this is discussed further in Chapter 6). Enquiry into practice: Teacher pedagogic knowledge Teacher preparation regimes vary from country to country and may shift over time. How familiar are you with the ideas and theorists referred to earlier in this chapter? Bloom’s taxonomies, Piaget’s levels of cognitive development, Vygotsky’s ideas about supporting development etc.? Which of these ideas are familiar to your colleagues? (Does this depend on when and how they qualified as a teacher?) To what extent do your teaching colleagues feel these different ideas are substantiated through their experience of teaching, and which do they consider most useful in planning their teaching? Perhaps these enquiry questions could be the basis of a useful departmental discussion or a focus group of interested colleagues open to learning about and from each other’s experiences.

Suggested further reading Kind, V. (2009). Pedagogical content knowledge in science education: Perspectives and potential for progress. Studies in Science Education, 45(2), 169–204. Moore, A. (2000). Teaching and Learning: Pedagogy, Curriculum and Culture. London: RoutledgeFalmer. Rollnick, M., & Mavhunga, E. (2017). Pedagogical content knowledge. In K. S. Taber & B. Akpan (Eds.), Science Education: An International Course Companion (pp. 507–522). Rotterdam: Sense Publishers. Saleh, I. M., & Khine, M. S. (Eds.) (2009). Fostering Scientific Habits of Mind: Pedagogical Knowledge and Best Practices in Science Education. Rotterdam: Sense Publishers.

Identifying and Sequencing Learning Quanta

Chapter outline The role of memory in learning Principles of ‘constructivist’ teaching Suggested further reading

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This chapter considers issues of planning teaching in terms of subject content and student learning. The focus is how to break up and organise subject matter for teaching. This relates to what is often termed a ‘constructivist’ perspective on teaching and learning (Taber, 2009). There are three key issues that will underpin this chapter: (i) the order in which material is presented; (ii) the ‘grain size’ of teaching material most suitable to support learning; and (iii) linking the presentation of subject matter to students’ existing thinking (the latter point being developed further in the next chapter). This chapter will be informed by a constructivist perspective that suggests that the learning of conceptual material is iterative, incremental and interpretive (Taber, 2014). As some background to these ideas, the chapter begins with a consideration of the nature of human memory. Research into human memory suggests that there are features of human cognition that have major implications for how people learn, and so how teachers can best support effective learning. Having some familiarity with some of the key ideas is therefore important to support teaching that is consistent with scientific evidence.

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The role of memory in learning There are different types of memory processes, which have different properties. Here I will distinguish between three distinct ‘components’ of the ‘system’. The language here reflects how it is sometimes helpful to think of cognition as supported by an apparatus for information processing, where there is input (e.g. hearing the teacher’s voice) that is processed, and may feed into an output (e.g. answering a teacher’s question). A comparison that is sometimes made is between the brain and an electronic computer: there are certainly similarities, but also some important differences (see the comments on analogies in Chapter 3). The human brain existed long before modern computers, so perhaps it tells us something about the opacity of its working that we often make the unfamiliar (brain) familiar by analogy with the more familiar computer. The three memory components will be referred to here as ‘buffers’, ‘working memory’ and ‘substantial representations’. Buffers store information only for short periods of time (typically less than a second). For example, sensory information is processed which leads to some information being transferred into buffers from which it can be accessed for conscious processing. However, not all that information is accessed before it is ‘overwritten’ by new information being directed through the system from subsequent sensory input (Dehaene et al., 2006). In terms of the operation of a brain, these buffers are forms of memory – but they are not relevant to our everyday notions of memory in terms of remembering information over days and years.

Limitations of working memory Working memory is a core component of the system. It is a processing space where we can work on information. Working memory includes separate short-term memories for holding verbal and visual information that is being processed, but also apparatus to allow us to ‘mentipulate’ that information – as when we make sense of an analogy by comparing the source and target domains. The two key features of working memory worth bearing in mind in teaching are (a) that it has a very limited capacity and (b) that (because of the way capacity needs to be understood) its operation biases it towards prior knowledge. We can understand the capacity of working memory as being set out in terms of chunks of information (a notion explored below). For a long time, it was commonly estimated that a typical adult’s working memory can handle about seven chunks of information at one time. It is now considered this might be an overestimate! Certainly, when most people are tested to recall unfamiliar lists of random numbers or words their performance suggests this is all that can be managed. However, there are some exceptions, and indeed very occasionally there have been cases of people who seem to be able to recall, after one exposure, very long lists. There may be exceedingly rare cases where this is actually due to an abnormality. Luria (1987) reported one case of a man (Solomon Shereshevsky) who could recall long complex formulae (which he had no understanding of) that he had been exposed to only once, when

Identifying and Sequencing Learning Quanta tested months or years later. This seems like an amazing gift. However, it proved to be quite the opposite. Someone who seems able to remember everything they are exposed to actually finds it very difficult to function normally. Luria found that ‘soaking up’ information in this way seemed to mean there was no sense of knowing what information to value and prioritise. ‘Forgetting’ most information seems to actually be an important factor in managing our knowledge. As one example, Shereshevsky was said to have had difficulties recognising faces, not because he did not remember them, but rather because he remembered them exactly as he had seen them (a particular expression, under particular lighting conditions), rather than being able to abstract the features which would be invariant on different occasions. However, there are also people who are not abnormal but develop techniques and strategies for learning enormous lists when tested (Ericsson, Chase & Faloon, 1980). This relates to what counts as a chunk of information. Human memory allows us to associate new learning with material we have previously learnt. When our knowledge is strongly linked and integrated, we can treat quite complex information as a single chunk. Consider the following examples: A: Potassium dichromate, K2Cr2O7, is a hexavalent compound of chromium commonly used as an oxidising agent. B:  Animalia – Arthropoda – Insecta – Hymenoptera – Apidae – Apis-mellifera. C: The electron is a lepton obeying fermionic statistics with mass 9.1 × 10−31 kg, charge 1.6 × 10−19 C, and spin 1/2. D:  Court – Wake – Lizard – Islands – Larks – Starless – Red.

To some readers, the first three examples will be somewhat familiar as part of their existing knowledge. Others might not recognise the specifics of all these examples, but can still understand the concepts and system in which the item makes sense. To most science teachers, each of these three examples will relate to some degree to science they have studied at some time, so existing knowledge and understanding is automatically drawn upon, making the examples more meaningful than they might appear to many school students. Probably, for most readers, these examples are not equally familiar. This offers the basis for a simple challenge. Commit these four examples to memory (rereading the lines as many times as you wish) and then write out the recalled information when (a) you finish reading this chapter and (b) you complete the book. Can you recall the information perfectly? Some simple hypotheses suggest themselves (you may feel that a ‘fair’ test requires you to not read these points until after you have completed the ‘experiment’): If, like many science teachers, examples A–C link to your subject knowledge strengths differentially, you are more likely to make mistakes in the example that links to your ‘weakest’ area of science knowledge. zzIf you find example C very familiar, you are more likely to offer a version with the right information mis-sequenced than get the right sequence with the wrong values (as the sequence is somewhat arbitrary). zz

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MasterClass in Science Education If you are a biologist, you are less likely to mis-sequence the information in example B than a nonbiologist who manages to remember the terms (as the ordering is not arbitrary, and links to an underlying structure that biologists are very familiar with).

zz

It is also the case that your science expertise can help you fill in missing detail that recall does not readily provide. So, in example A, remembering the formula can help select the term ‘hexavalent’ if you were not sure what you had read (was it that or ‘heptavalent’?), and conversely, if you could not recall the formula, the combination of ‘dichromate’ and ‘hexavalent’ could allow you to work it out. Similarly, in example C, the reference to Fermi–Dirac statistics implies something about the possible values of spin (was it 0, 1? No, it could not have been), or recalling the spin value tells you which statistics are relevant. That said, if you have strengths in chemistry or physics, it is extremely unlikely you would get the spin of an electron wrong: recalling the information from the statement is supported by your having long ago represented it in memory. Example D is not derived from an area of science at all: most readers will find they have no particular background knowledge to relate this list to. It is similar in surface structure to example B, yet unless one recognises the pattern behind the sequence, or constructs a story around the terms, D seems an arbitrary list of everyday words. Enquiry into practice: What can learners hold in mind? You could easily modify the activity above to explore how much your students can hold in mind at one time. Perhaps consider the next topic you are to teach a class, and then select a set of key terms or a few core statements, and have these displayed at the start of lesson. You might deliberately include a mixture of items: some already familiar and some that you expect students will not have come across. You could draw students’ attention to this, perhaps pointing out that this is part of a topic to be taught later in the course. At the end of the class, ask students to write down any of the terms/statements they can recall being displayed at the start (making it clear this is not a formal assessment). You could collect these in or, perhaps better, display the original information again and ask which items people had written down. Were there any distorted versions of items, or indeed examples of ‘recalled’ items that did not relate to the displayed items? (Research suggests people often ‘remember’ things that were not part of the stimulus.) How much material can students typically recall in a situation like this where they are not asked to actively learn the material?

Seeing at the learner’s resolution An important consequence for teachers is that in their judging how challenging the material presented in teaching is, it has to be understood at the learner’s resolution – as it will appear from the perspective of their existing knowledge and understanding. A corollary here, then, is that when one is teaching classes where some students have better, or better organised,

Identifying and Sequencing Learning Quanta prior knowledge than others, the same teaching presentation will be more difficult to follow for some in the class than others. What can be processed within the working memory of some students may exceed that of some of their classmates. And of course, ‘classes where some students have better, or better organised, prior knowledge than others’ could just be truncated to ‘classes’: when teaching (any) class, the same teaching presentation will be more difficult to follow for some students than others. The bias ‘built’ into the cognitive system then is that we can handle familiar material, which can be chunked into complex meaningful wholes, more readily than novel material. This leads to two of the key principles of constructivist approaches to teaching: (1) break up new material into manageable learning quanta; (2) help students associate new learning with their existing experiences, knowledge and understanding (e.g. using the techniques discussed in Chapter 3). As we are able to work more readily with existing knowledge – especially when it is highly structured – than unfamiliar material, it can sometimes be difficult to challenge learners’ existing ideas. This becomes important when students arrive in class with alternative conceptions that are inconsistent with the science to be learnt (discussed in Chapter 6). Sometimes students hold on to their ‘misconceptions’ (alternative conceptions) despite repeated attempts to correct this. Even when they seem to have learnt the scientific account, we may find they soon revert to using their pre-existing alternative ways of thinking (for example in assessments).

Brains do not ‘store’ information It might be suggested that most readers should forget everything they think they know about how human memory stores information as it is likely to be misconceived (although, as has just been pointed out, forgetting existing ideas is difficult!). A folk model of human longterm memory is that it is like computer memory: information is written onto some kind of storage medium, and later it can be read out in an identical form. In the computer, this type of memory is quite distinct from the processing apparatus. So, for example, it is possible to move the storage device (USB stick, DVD, hard drive etc.) to another computer and read the information in perfect fidelity. Human memory seems to be quite different in a number of ways. For one thing memories often seem to be represented more diffusely across the brain (as if part of a memory is on the hard drive, but part is on a USB stick, if that is not taking liberties with the analogy). Perhaps more significantly, the apparatus which processes information is not entirely distinct from the apparatus for the storage of information. Rather than have a specialised device for memory storage and a separate specialised device for processing, there seems to be some overlap in these functions. If one wanted to build something to store discrete memories in good fidelity, one would not design a brain. Presumably human brains have evolved to be like they are because they supported evolutionary fitness, which may mean something other than being good at remembering things accurately and in great detail. The human brain seems to be very good at making sense of

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MasterClass in Science Education experience – at building and revising an internal model of the world which can help us interpret our experiences. Generally, this does not require an ability to keep an accurate record of all our past experiences, neatly filed away, but rather requires having a basis for responding relatively quickly to phenomena in our environment (a food source, a flood, a rockfall, a predator). Our brains are not accurate memory devices, but then they have evolved to do something much more complex than reproduce large amounts of information in high fidelity. Our brains support a sense of identity – who we are, how we came to be who and where we are, the story of our lives so far – but that does not require that the accounts we hold of ourselves are complete, correctly sequenced or indeed accurate. Arguably, human happiness is enhanced by the ways we develop subjective accounts of ourselves. Building up a personal story of ourselves that helps us survive mistakes, failures, rejection, bereavement, physical and mental frailties, reduced functioning as we age and so forth may be necessary for resilience and well-being, even when the resulting narrative would seem distorted (biased) to any detached biographer. Our long-term memory is used to interpret our perceptions of the world, and can often be updated in doing so. We do not ‘store’ information as much as build a representation of experience – a model of our personally experienced world – which is gradually modified on the basis of new experiences. As noted above, there is a bias in the system towards existing ways of thinking and understanding such that change in our models of experience is usually (unless we experience trauma) gradual and incremental. The brain will abstract common features from experiences, and then develop generalisations (so something we remember may be a composite or hybrid from several similar experiences). The brain also seems to, over time (and some think during sleep), work to find links between material represented, and even to modify representations to bring different features into greater coherence. The external natural world is presumably a coherent and consistent reality, but our perceptions may be partial, misconstrued and misinformed – so if the brain’s main function is to provide an effective model of the world to inform our actions, it should not be surprising that it has evolved to edit the representation of our experiences (in effect, our memories) to develop a model which is more systematic, better organised and, as far as possible, coherent. This is not of course to say that we cannot form memories of specific events (especially emotionally charged events that trigger high levels of adrenaline), nor that our memories are always wrong, but it is probably the case that most people overestimate both the accuracy of their memories and the extent to which what they remember is linked to specific discrete experiences. Memory tends to hybridise and aggregate more than we realise. The memories we bring to mind are often being constructed from fragments that are patched together, and with gaps filled in with best guesses, even when what we subjectively experience seems a clear, coherent and integrated memory. It is not strictly appropriate to consider the laying down of memories as the storage of experiences, but rather it is appropriate to consider this as representing them.

Identifying and Sequencing Learning Quanta It also seems that the process of representing complex information is not immediate and instantaneous. Research suggests that when new meaningful learning occurs (that is, the learning of material we make sense of in terms of prior learning), the initial linkages made between new and prior learning are temporary, but may then become replaced by more permanent links over time – although usually only if the learning is reinforced. So, even when it seems that students can demonstrate new learning at the end of a lesson, or when asked in the next lesson, that learning needs to be reinforced if memory is to be consolidated sufficiently for students to be likely to access that learning and ‘bring it to mind’ some months later. Again, what might seem like a limitation of the system is perhaps actually an adaption. It could seem that having a perfect recall of all our experiences and remembering everything we have ever been told would be exceptionally useful. But Luria’s patient, Solomon Shereshevsky, who seemed to have just this ability, suffered an inability to recognise what was important. The ability to sift what seems worth noting from all the ephemera we are all exposed to everyday (consider every item of every news broadcast; every snatch of conversation overheard on the street; every weather forecast ever heard; every advertising jingle or motto you have been exposed to; a perfect recollection of every conversation ever had with shopkeepers, bus and taxi drivers, relatives, friends and strangers; every sports result announced; every line of every song and film; etc.) appears to involve allowing most of our experiences to have little effect on us. Luria’s patient had difficulty holding down a job and functioning normally in life. Not forgetting was a torment not a pleasure. To summarise, human memory can be considered to comprise three types of component: a) Short-term buffers – these act as stores of information operating over a very small timescale, and much of their content is lost without being substantially processed (and so becoming available to be later remembered). b) Working memory – which is the locus of deliberate thinking and problem-solving. It has a very modest capacity in terms of the chunks of information than can be ‘mentipulated’ at one time; however, quite complex material already integrated in ‘long-term memory’ can be accessed as single chunks of information. It therefore is able to deal with familiar contexts and examples more readily than unfamiliar material that seems unrelated to previous learning. c) Long-term memory – which is a representation of past experience of the world and our lives that is constantly being updated in terms of new experience, and which is subject to editing processes that work towards building a more consistent and coherent representation. This resource allows the generation of the ‘memories’ we experience, although these are often based on accounts that have become hybridised and smoothed, and which may be built from incomplete representations that the brain ‘fills in’ (on the basis of more general expectations and experiences) to offer a full picture.

This apparatus serves us well in most aspects of everyday life, but it has not evolved in response to the particular demands of studying academic subjects in school.

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Principles of ‘constructivist’ teaching This consideration of human cognition leads us to appreciate that student learning is usually incremental (occurs in small steps) and interpretive (as new information is understood in terms of the resources available – that is, existing ways of thinking), and so iterative (the steps build from where the learner is). This informs a view of the kinds of pedagogy that will be effective in engaging human learning processes.

Learning is iterative What is meant by saying that learning is iterative is that it builds up over time. What a student can learn today is highly dependent on what they learnt in the past. Moreover, what a student learns now will influence what they are ready to learn in the future. Our concern here is to consider the implications of research for learning on the process of teaching (which was understood in Chapter 4 to include aspects of planning as well as actually what is done in the classroom). However, it is worth noting that the evaluation of teaching becomes highly challenging when what a student learns in one classroom is partially dependent on their previous learning experiences (in and out of school, in the same and different classrooms, recently and many years before, etc.), suggesting that a classroom visitor observing one lesson is sampling one small part of a complex ongoing long-term process – making quick judgements about whether learning takes place ‘in’ the lesson rather questionable. In terms of subject matter, there are some simple enough principles that can support teachers in responding to the challenge of the iterative nature of teaching: Effective teaching is based on conceptual analysis of subject matter. Effective teaching is supported by diagnostic assessment.

zz zz

Analysing the concepts A science subject or topic can be considered to have a conceptual structure – that is, it can be modelled as a kind of concept map where the different key ideas are linked together (for example, by propositional statements). Indeed, actually using something like concept mapping (see Figure 5.1) as a tool to clarify the conceptual structure of a topic to be taught can be really useful. A range of kinds of links might be included. Some of these refer to core scientific propositions (‘energy is conserved’) or observed relationships (‘gas pressure increases with temperature’). Others may relate to definitions (‘amphoteric substances can show acidic or basic behaviour’), or applications (‘electromagnetic induction is used in transformers (mains adapters) to connect low voltage equipment to the mains supply’) or examples (‘nickel is a ferromagnetic material’).

Identifying and Sequencing Learning Quanta

Figure 5.1  It may be helpful to literally ‘map out’ the relationship between key ideas in a topic, as in this concept map of some of the key ideas in this chapter.

Analysing such relationships between concepts can help plan a logical course through material. In particular, it helps clarify what should sensibly be taught before other ideas. Following someone else’s path through a topic without undertaking your own conceptual analysis is an invitation to run into unforeseen problems when students do not follow the logic of the topic. Ideally, teachers have strong subject knowledge in the topics they will teach (see Chapter 4), but this can bring the risk of an expert launching into a presentation of material assuming prior knowledge students may not have. Appropriate conceptual analysis is a useful component of a strategy that can potentially avoid this. Here are some examples of the kinds of problems to be avoided: looking to explain natural selection before students have a good basic understanding of what scientists mean by a species; zzseeking to teach about elements and compounds before considering the notion of substance in chemistry; 23 zzrepresenting Avogadro’s number as 6 × 10 before students have been familiarised with standard scientific notion; zz

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MasterClass in Science Education referring to the loadings on a spring in terms of newtons before students have learnt about the relationship between mass and force (in a gravitational field); zzreferring to oxides as basic, when students have been introduced only to the concept of alkalis, not bases. zz

There are clearly a great many other examples across science topics. In my own teaching, I found that when the topic of hydrogen bonding was introduced in chemistry, some students already had the notion that a hydrogen bond was a covalent bond to a hydrogen atom. They had not been explicitly taught wrong information but had only learnt about a limited number of types of bond (ionic, covalent, metallic) in their foundation chemistry courses before finding hydrogen bonds referred to (but not explained) in their advanced biology classes. The biology teachers either had assumed that students already understood the concept of hydrogen bonding or possibly did not feel students needed to know what hydrogen bonds are to understand their role in biological structures. In the absence of any clarification, students had inferred an incorrect meaning of the term ‘hydrogen bond’ to fit with their existing knowledge. (Many examples of students’ ‘alternative’ thinking about science concepts and topics are discussed in Taber, 2014.)

Bootstrapping concepts Sometimes a careful analysis of the concepts to be taught suggests quite obviously the best ordering of topics. So, if pressure is to be defined in terms of force per unit area, then it probably makes sense not to try to teach about pressure before teaching something about force. It probably makes sense to think about heat capacity before specific heat capacity. That is, it is conceptually more straightforward to talk about examples of how there is found to be: (i) a direct relationship between heat that flows into/out of specific objects and the measured temperature change

before adding the additional consideration of mass to discuss the more abstract notion of (ii) the relationship between heat that flows into/out of samples of materials and the quotient of the temperature change and their mass.

However, some topics present more problems for conceptual analysis. Consider the notion of a chemical element. This is traditionally defined in terms of being a chemical substance that cannot be broken down into anything simpler by chemical means (cf. a compound). It does not make sense to offer this definition until students have been taught what is meant by a substance (sometimes referred to as a ‘single substance’) in chemistry. Yet although students may learn the definition, that is not enough to understand its meaning and significance. A student can learn that ‘an element is a chemical substance that cannot be broken down into anything simpler by chemical means’ by rote – that is, learn the form of words as if a line of poetry. This does not imply understanding. They might readily apply the definition: I – Teacher:   ‘Osmium is an element. Leda, what does this mean?’ R – Leda:  ‘Osmium is a substance that cannot be broken down into anything simpler by chemical means’.

Identifying and Sequencing Learning Quanta E – Teacher:  ‘Yes, good.’  (Note: the common initiation–response–evaluation (IRE) structure of classroom talk is introduced in Chapter 4.) I – Teacher:  ‘Balvinder, can you give me any examples of substances which cannot be changed into anything simpler by chemical means?’  [The teacher, having read it is important to give pupils thinking time, pauses and waits for Balvinder to consider a response.]  [Balvinder thinks: ‘Substances which cannot be changed into anything simpler by chemical means are called “elements”. Oxygen, hydrogen, nitrogen, iron, sulphur, chlorine – I think they are all elements.’] R – Balvinder:  ‘I think that oxygen, and hydrogen, and nitrogen, and iron, and sulphur, and chlorine, wouldn’t they all be examples?’ E – Teacher:   ‘Yes, very good, there’s a few examples there.’ I – Teacher:  ‘Does anyone remember what we call substances of this kind in chemistry? Hands up please.’

However, this level of application demonstrates only a limited understanding of the concept. Balvinder is able to make logical deductions (see Chapter 9) and would equally be able to apply the logic to other examples, without deeply understanding the concepts. The problem with the definition is that the average school learner has no way of knowing whether a substance can be broken down by chemical means. If a student was asked to carefully heat some powdered copper in a crucible, and to carefully heat some powdered copper carbonate in another crucible, then they would likely observe that in each case the powder changed colour. If they did not already know about the reactions they were initiating, then it would not be obvious that in one case they were breaking down a substance to substances ‘less compounded’, and in the other case were compounding different substances together. There is also the danger of circularity; for example, what makes one process chemical and another not chemical. Uranium isotopes are separated by use of centrifuges (albeit somewhat more complex ones than found in school laboratories) because they have different physical (sic, not chemical) properties – but that does not count as a chemical means of decomposition, and a sample of uranium, which is a mixture of isotopes, is an element – a single substance. Our definition of ‘element’ depends on our definition of ‘chemical means’, but that is likely to be no clearer to the novice than the idea of ‘element’ it is meant to help explain. Of course, we might decide to define an element in a different way – as containing only one kind of atom, for example. This assumes pupils are ready to be introduced to the very abstract notion of the atom (see Chapter 12). However, then we have to define ‘one kind of atom’ in a particular way (proton number) and treat atoms with different masses or in different energy states but with the same proton number as of one kind. We also have to ignore how the atoms join to each other in the element. Red phosphorus is the same element as brown phosphorus. Poisonous ozone is the same element as life-supporting oxygen. Iron that has a close-packed structure is the same element as the body-centred crystal version, which has different properties – for example, of particular significance to steelmaking, the

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MasterClass in Science Education amount of carbon that will ‘dissolve’ in the metal. The carbon mixed with clay to make pencil ‘lead’ is the same element as the carbon crystals mounted in gold in jewellery, even if it looks grey and makes marks on paper similar to those made by an element that is also called ‘lead’. For the student, however, there is no more reason to believe the teacher who claims that diamond and graphite consist of the same kind of atom than there is to simply accept that graphite and diamond are both forms of the element carbon which cannot be broken down to anything simpler by chemical means – especially when sufficient heating of either would lead to no obvious residue. So again, from the student’s perspective, the teacher may seem to be offering little more than a kind of circular argument – you should believe in elements as basic types of substance (even if there is no clear evidence you can yet appreciate for that idea, and you only have direct experience of a few of these elements) because elements align with basic types of atom (of which you have no direct experience at all). Some might say that the student should believe what the teacher says because the teacher is an authority – but that is rather antithetical to the ethos of science (see Chapter 10). If we want to model the processes and nature of science in school science, then we had better provide convincing arguments and evidence rather than ask students to learn this because I say so, or the textbook says so, or even because a Newton or Curie or Darwin said so. The point here is that some core ideas are subtle, and so are not easily summarised by simple definitions that will make sense to beginners. Sometimes we do have to teach an idea ‘by authority’ initially, so we can later return to and treat it more conceptually. This is not ideal. The educational thinker Jerome Bruner developed the idea of the spiral curriculum (introduced in Chapter 4) – returning to ideas periodically during schooling, to provide progression in understanding; so, electricity on the university entrance level course involves a more developed treatment than in the primary school – with intermediate treatments in between. However, Bruner wrote of teaching simplified ideas in an intellectually honest way – offering an authentic kernel of the technical idea or concept, even if initially stripped of some of its complexity. Sometimes, however, we do have to bootstrap teaching – asking the students to take on trust our definitions or claims with the promise (that we must honour) that we will come back to those ideas. Over several years of studying and thinking about chemical reactions, the student can develop a more meaningful notion of what we mean by ‘element’ and ‘chemical change’ (and so ‘chemical means’).

Meaningful learning To say that we have to initially teach some ideas by authority need not mean teaching by rote. Rote learning is learning material ‘by heart’ without any understanding. Teachers will be well aware that most students (and indeed most of us) struggle to learn much material by rote, but rather tend to learn things more easily when we can make some sense of them. It was the educational psychologist David Ausubel (2000) who emphasised the distinction between rote and – what he called – meaningful learning. Meaningful learning occurs when

Identifying and Sequencing Learning Quanta the student can relate new material to some existing knowledge or experience. Skilled teachers are very good at making material meaningful for learners by relating teaching to their existing knowledge and experience (see Chapter 4). Meaningful learning is, however, not necessarily accurate, or indeed the intended, learning. ‘Meaningful’ implies that a learner found a way to understand teaching in relation to their existing ‘conceptual resources’ (their existing ideas, beliefs etc.), not that they understood the material in a canonical way. Indeed, a major issue in science education is how students commonly develop their own alternative meanings for taught material that are at odds with what the teacher intended and the curriculum specified. The student interprets teaching, but sometimes that is a ‘misinterpretation’ from the teacher’s perspective. This is explored further in Chapter 6. Teachers use various kinds of models and representations in their teaching to help make concepts seem concrete and to simplify the complicated, and, in general, to make the unfamiliar familiar.

Making the unfamiliar familiar As suggested in Chapter 3, the task of teaching might be considered as making the unfamiliar familiar. What was unknown, not understood, out of reach or beyond a learner’s capacity becomes known, understood, attainable and doable after effective teaching. Yet some people suggest there is a paradox here. According to the tenets of constructivism, new knowledge is built from existing conceptual resources and new intellectual capabilities are built upon existing cognitive skills. Yet, if we apply this too strictly, it could imply that all we can ever know is a reshuffling of what we already know, and so what we must have always known in some latent sense. Then we would have to consider every newborn to already, at some level, ‘know’ everything they would ever learn. There is a reflection here of the debate about the nature of developing scientific knowledge where the logical process of induction (long thought to be the basis of scientific discovery) can not offer assured generalisation beyond the examples specifically examined (this is discussed in Chapter 9). Interestingly, one of the earliest forms of pedagogy, the Platonic or Socratic dialogue – where a person is led to some conclusion through a sequence of questions – assumed that what was being learnt was knowledge already in a sense latent in the learner, and just being uncovered and made explicit. However, that view is not generally considered tenable today, and it is now widely considered that the process of scientific discovery requires an imaginative leap that goes beyond what is logically required by the available evidence. In a similar way, just as scientific knowledge cannot be developed purely through induction, student learning cannot be seen purely as a kind of reorganisation of prior knowledge.

Learning depends upon accessible resources for making sense The constructivist perspective is based on a more modest claim that considers the role of two types of resource for learning. These might be classed as internal resources (such

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MasterClass in Science Education as  thinking  skills, existing knowledge, memories of personal experiences) and external resources in the learner’s environment (which includes the teacher, classmates, access to the internet). In this perspective, new learning is severely constrained by the available mental (internal) resources, which limit the extent to which new knowledge can be constructed using available ‘external’ resources. So, learning involves two types of resource – those internal to the learner (which might be understood as system resources) and those external (which might in this model be considered as environmental resources). Sometimes new learning can be based purely on internal resources (in the sense that no ‘input’ from the environment is needed at that moment – there is a moment of insight that is based on some kind of interrogation and reorganisation of internal resources), but in general, learning involves an interaction between these two types of resource. This model was in particular championed by the developmental psychologist Jean Piaget, who explored child development from a biological perspective. Piaget (1970/1972) undertook a programme of research over many years, and developed a theoretical perspective for his work that he labelled as ‘genetic epistemology’ because he was concerned with the origins of knowledge. Not all aspects of Piaget’s thinking are widely accepted today – as often tends to happen over time with those recognised as great minds (cf. Newton, Darwin, Dalton). With the benefit of hindsight, some of the greatest achievements may seem commonplace (because what was seen as revolutionary at the time has now become the orthodox way of thinking). It is often only possible for later research to throw doubts upon the findings of such figures because of the foundations they provided for others to take work in a field forward. Piaget considered the individual as having been endowed by evolution with the cognitive apparatus for building structures to make sense of the world and operate within it. Moreover, Piaget thought that there was a bootstrapping process at work such that the young child was equipped to interact in the world in ways that allowed them to build more complex cognitive tools. Piaget saw this as a step-like process with four main stages, such that children were able to pass through different stages of development by operating on the world with existing cognitive tools in a way that provided the basis for the next stage of development. So the cognitive (thinking) tools available to a child at an early stage supported operations that over time allowed them to build up the next level of thinking tools. Piaget’s work can be considered as a research programme in the sense in which the philosopher Imre Lakatos (1970) described science as being organised through such programmes. There were certain hard-core commitments that characterised the programme and helped guide the direction the research took. So, for example: Piaget described the ‘epistemic subject’, a kind of ‘everyperson’, because he considered that all normal humans pass through the same developmental trajectory – that is, all children will pass through the same stages in the same order.

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Identifying and Sequencing Learning Quanta Although there were individual differences between children, Piaget’s research suggested that there are typical ages at which transitions between stages occur. zzPiaget focused on domain-general cognition because he considered that core cognitive skills are applied across domains of experience. zz

Piaget’s work has been very influential in science education. The most developed of Piaget’s four main stages is known as ‘formal operational thinking’. A person who has achieved formal operation thought is able to treat abstract ideas as mental objects to be ‘mentipulated’. Researchers suggested that much of the science content of secondary (high) school science curricula could only be fully mastered by people who can undertake formal operations (Shayer & Adey, 1981); yet research also suggested that many students of that age were still in transition from the earlier stage of concrete operations. This provided one rationale for explaining why so many students struggled in science. Whilst the detail of Piaget’s scheme has been questioned and critiqued, and so is no longer as widely accepted as it once was, Piaget does help us focus on the abstract nature of much that is taught in school science, and appreciate how challenging this is for many students. In biology we teach about changes that have occurred on average in populations over many thousands of generations, and about how chromosomes are shuffled during meiotic prophase to allow new unique genetic combinations during fertilisation; in chemistry we teach how the acidic properties of substances are linked to hydrated hydrogen ions, and how salt colour is linked to the relative energy levels of d-orbitals; in physics we ask students to distinguish heat from temperature (and mass from weight) and consider how the flow of current in a conductor interacts with a magnetic field. These ideas, and many others we teach, are abstract and some distance from students’ everyday experiences. Thus, there is a need to make the unfamiliar familiar, and to help students construct new knowledge through offering carefully planned sequences of manageable learning quanta.

Suggested further reading Duschl, R., Maeng, S., & Sezen, A. (2011). Learning progressions and teaching sequences: A review and analysis. Studies in Science Education, 47(2), 123–182. Taber, K. S. (2014). Student Thinking and Learning in Science: Perspectives on the Nature and Development of Learners’ Ideas. New York: Routledge.

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The Nature of Students’ Scientific Knowledge

Chapter outline Minding our language about knowledge? Diversity in students’ knowledge of science Diagnostic assessment Suggested further reading

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There is an immense research literature relating to learners’ ideas and thinking in science (for a general introduction to this area, see Taber, 2014). This chapter offers an overview of some of the key principles.

Minding our language about knowledge? In this chapter, I refer to students’ scientific knowledge or their knowledge of science. Earlier in the book (see Chapter 3), it was suggested that ‘knowledge’ is quite a tricky notion. The traditional idea that something counts as knowledge only when it is true, justified, belief was found to be unhelpful in thinking about science. By the nature of science, all scientific ‘knowledge’ is, at least in principle, provisional, and so open to revision in the light of new evidence. Given this, and the lessons from history showing how some scientific ideas attract strong commitment that is difficult to shift in the light of apparently falsifying evidence, science should not be about believing things in any absolute sense (a principle developed in

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MasterClass in Science Education Chapter 10). Belief in caloric, phlogiston, spontaneous generation and many other ideas has proved unhelpful, and so we should be wary of ‘belief ’ in dark energy or climate change or any other current scientific ideas. The suggestion that scientists ‘believe’ in a neo-Darwinian model of evolution may actually make teaching natural selection to some students more difficult (see Chapter 11). That is certainly not to suggest we should reject these ideas, or commit to disbelief instead of belief. Not ‘believing’ in climate change is appropriate, but rejecting or disbelieving climate change would be irresponsible in the face of the strong scientific case. Rather, ‘belief ’ is not the appropriate criterion or ‘Discourse’. If we want to induct learners into scientific ways of thinking and practices, then we should avoid talking in terms of belief. Of course this is tricky because we have to balance precision of language with clear communication. To say something like: Scientists have developed an evidence-based model of disease transmission based around the hypothesis that some microorganisms play a causative role in some diseases.

zz

puts a much greater burden on the listener than: Scientists believe that many diseases are caused by microorganisms. Scientists have shown that many diseases are caused by microorganisms. zzScientists now know that many diseases are caused by microorganisms. zzMany diseases are caused by microorganisms. zz zz

These simpler statements communicate more directly, but they lack important caveats. In this example, we might feel that the scientific knowledge is so secure there is no problem. We might be less comfortable with: Scientists believe that the climate is changing due to human activities. Scientists have shown that the climate is changing due to human activities. zzScientists now know that the climate is changing due to human activities. zzThe climate is changing due to human activities. zz zz

In this example, some form of caveat seems necessary, but it might be difficult to know how we draw a dividing line between these two types of cases. What about: Scientists believe that organisms with a genome containing DNA evolved from earlier forms having a genome based on RNA. zzScientists have shown that organisms with a genome containing DNA evolved from earlier forms having a genome based on RNA. zzScientists now know that organisms with a genome containing DNA evolved from earlier forms having a genome based on RNA. zzOrganisms with a genome containing DNA evolved from earlier forms having a genome based on RNA. zz

The Nature of Students’ Scientific Knowledge A strong objection here would be that actually the ‘RNA world’ is just a hypothesis, and although it has been strongly argued by some scientists, it is not something that can be considered as fully accepted by science. Most scientists do not believe that organisms with a genome containing DNA evolved from earlier forms having a genome based on RNA – if only because most scientists do not know enough about the topic to have a strong view. It is difficult to know at what point such definitive statements could be justified for many things met in science given that all science is meant to be in principle provisional, and always open to new evidence. Learning science involves being inducted, to some extent, into an unfamiliar community of practice, and a core aspect of this relates to issues of language. A problem here is that professional scientists often talk as though things that are technically uncertain are now known and proven. They may do this when talking to each other, because it is clear to their peers that the conversation takes place within the assumptions of a particular field and within the wider norms of science. A parallel might be actors in a play or film. It is accepted by all involved that they are playing a part and so they do not feel the need to preface every speech with ‘according to my character … ’ or ‘the writer of the script suggests I say … ’. Similarly, in scientific discourse many of the caveats (‘current evidence seems to suggest … ’; ‘the accepted model would imply … ’) can be taken for granted among peers. When talking to the public, scientists often also exclude important provisos, whether as a matter of habit or to keep messages clear and simple.

Enquiry into practice: How do you present scientific knowledge? Audio record some of your teaching when you are explaining and discussing science. Listen back to your presentation sentence by sentence. Try to shift your focus away from your intended meaning to the precise words used. Does the language you use suggest that scientific ideas are products constructed in human imagination, which are presented as provisional and conjectural accounts of nature? Do you present scientific ideas as laws, principles, theories, models etc. (rather than matters of fact)? Could the way you use language suggest to those listening (your students) that theoretical and provisional ideas are more certain than they are, or that theories and models are considered by scientists as absolute and definitive (for all time) accounts of how nature actually is? You might also want to interview some of the students in your classes to find out how they understand the status of the ideas you have introduced in your lessons.

A way of thinking about scientific ideas Many scientific notions are formulated as models and intended not as ‘the truth’ but as ways of thinking about phenomena. The ideal gas equation provides a useful tool for thinking about and modelling gas behaviour, even though it strictly applies only to gases that are by

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MasterClass in Science Education definition non-existent (i.e. having particles of no volume, and which do not interact at any separation). Knowledge of the ideal gas equation is useful knowledge even if it is not a true description of the actual world; strong scientific knowledge of the equation would include understanding its status as a particular kind of theoretical knowledge and an awareness of its limitations given its unrealistic underlying assumptions. When one is considering school-age learners of science, the problems of defining knowledge in traditional ways are even more obvious. Much that is taught in school science concerns simplifications of current scientific knowledge – so even if we took scientific knowledge to be ‘true’ knowledge, a student who perfectly learnt the representation of the science presented in school science could not be said to have attained this. This would be an unhelpful position. We could simply abandon the word ‘knowledge’ as carrying unhelpful associations, but as it is widely used, we instead adopt an alternative definition. In Chapter 3, some historical examples of scientific ideas were discussed. It is clear that if science proceeds when new ideas develop or replace others, there must be periods when scientists have to understand and consider two different conceptual schemes – such as Priestley and the Lavoisiers analysing their results in terms of both the phlogiston theory and the oxygen theory. It makes sense to say that Priestley and the Lavoisiers all had knowledge that encompassed both schemes – even though the two approaches were contrary and could not both be correct.

Figure 6.1  An individual will hold a vast range of different conceptions, with widely varying properties.

The Nature of Students’ Scientific Knowledge So when one is considering scientists, a useful notion of knowledge needs to be inclusive. This is also true of science learners, especially when we want them to shift their thinking, to make sense of a new way of understanding at odds with their current understanding of some topic. It has been suggested that a suitable inclusive notion of knowledge here is ‘notions that the learner entertains as possible mental representations of some aspect of the world’ – or more simply ‘plausible mental constructions’ (Taber, 2013d, p. 176). So the components of a person’s knowledge may be considered as their conceptions (ways of conceptualising something) or personal constructs (construing of how things may be). In science education we often talk of student knowledge in terms of student conceptions (see Figure 6.1), or simply students’ ideas.

Diversity in students’ knowledge of science The extensive body of research into learners’ ideas in science has found a great deal of diversity both in terms of the ideas learners seem to have and in terms of the nature of those ideas (see Figure 6.1). This is not surprising when we consider that research participants have included very different populations from primary school children to postgraduate students and indeed beyond (teachers, for example). An obvious starting point is the extent to which learners’ ideas match scientific thinking. Before being taught science topics, learners often have already developed ideas on scientific topics. Sometimes these ideas are similar to, or at least consistent with, what they will be taught in school – but sometimes not. Then learners are said to have alternative conceptions (or intuitive or naive theories). When researchers began to find examples of student alternative conceptions, it was suggested that the role of the teacher was to identify and then challenge and seek to replace those ideas with more accurate scientific understanding. Some researchers reported that students developed alternative conceptions that were very tenacious and so very difficult to extinguish. However, some other commentators claimed that such ideas were not of great significance, and so were best ignored. Indeed, some suggested that putting a strong focus on students’ ideas that were contrary to science was only likely to reinforce those ideas and give them status through having been discussed in science lessons. This range of views is not especially helpful in informing teachers how to proceed. After decades of research, it now seems clear that we cannot treat all alternative ideas offered by students as having the same status. In some ways this is a bit like science itself: some ideas are very well evidenced and are considered to have the status of consensus ideas; in other areas, there are ranges of competing theories, each with their champions, but where many scientists in a field are keeping an open mind.

Student conceptions as learning impediments What is clear is that some alternative ideas that students may have can be very significant for learning. Here are three examples.

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MasterClass in Science Education Force and motion: Research has repeatedly shown that most people have the intuitive notion that there must be a force acting on a moving object in the direction of movement (this is sometimes called an impetus theory or F–v {force–velocity} thinking). Newtonian mechanics has a central principle of inertia that means that a net force causes a change in motion (i.e. F-a {force-acceleration} thinking) and that an object moving with uniform velocity is not subject to any net force. Research suggests that after study, many students maintain their intuitive notions, and soon disregard the account used in physics. Even students who have proved successful in using the scientific account in tests and examinations will revert to the intuitive account on occasions. Chemical bonds: Matter coheres because the tiny particles (quanticles, see Chapter 12) of which it is comprised bond together. These bonds result from interactions that can be most simply understood as electromagnetic. Bonds form and break because of the forces acting between the charges that matter is comprised of. Yet many students develop an alternative idea: that atoms want to fill their shells or acquire octets of electrons, and so they enter into arrangements to transfer and share electrons until the atoms involved are happy with their electron arrangements. This is a ludicrous idea: it is not only wrong, and often totally illogical (to explain why H2 and F2 react in these terms, as many students do, is not even coherent), but relies on atoms acting as conscious agents able to enter into social contracts. Yet it is extremely common, and is often retained despite advanced teaching in terms of scientific ideas about forces, orbitals, energy levels etc. Evolution: When students are taught about the scientific theory of natural selection, many misunderstand the neo-Darwinian model that they have been taught as a more Lamarckian model where acquired characteristics are inherited, i.e. a giraffe stretches its neck, and somehow passes on this trait (see Figure 6.2). Moreover, many other students come to science lessons ‘knowing’ that macroevolution, the appearance of totally new forms of living things by descent from other types of living things, simply does not happen.

Figure 6.2  What is learnt is not always what we thought we taught.

The Nature of Students’ Scientific Knowledge These ideas have different origins. The alternative conception of mechanics seems to be an abstraction from common experience of how things behave in the real world. The misunderstanding of natural selection is more interesting: it seems likely this is in part because what students are ready to learn, what they feel is viable and feasible, influences how they interpret and understand teaching. Rejecting evolution may for many students have intuitive aspects – our general experience is that living things come in fairly stable forms. However, those who are adamant that evolution has not occurred seem to go beyond just relying on their feelings of how the world is. This is often something they have learnt outside school, and is a strong commitment within their family or community (see Chapter 11). The alternative conceptual framework about chemical bonding, the octet framework, is in some ways more interesting as it is very unlikely that most children have grounded intuitions about how atoms behave (as they have no direct experience of atoms) and there are few students brought up in communities that have strong commitments to notions about how and why molecules form that they indoctrinate into their young. As with the case of natural selection, part of what is going on is presumably a matter of what makes sense to the student, so that when taught about chemical bonding, students are more likely to interpret teaching some ways than others. Yet this is an extensive conceptual framework, which seems to be adopted to some extent by most students in most chemistry classes, and which interferes with study at advanced levels (it has been found in university students studying chemistry). It seems likely that teaching actually encourages students to learn this way of thinking (see Figure 6.3). A particular issue may be the language used by teachers, especially if they use anthropomorphic language that is meant in a metaphorical sense (see Chapter 3), but which students may come to adopt as if the technical way of talking and thinking about molecules, ions and atoms. Enquiry into practice: Researching alternative conceptions For the next topic you are preparing to teach, investigate the reported common alternative conceptions (‘misconceptions’). If you do not have access to the research literature, you will find much relevant information from a careful Web search. Ask yourself: zz zz zz

how holding such ideas might interfere with understanding teaching; how you might find out if any of your students hold such conceptions; how you might use diagnosis of these conceptions to inform your classroom work.

Dimensions of conceptions Some alternative conceptions are tenacious; however, not all conceptions are of the same nature. It is not just that some conceptions better fit scientific accounts than others. Conceptions are also different in terms of:

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Figure 6.3  Teaching analogies, models and metaphors used to relate abstract ideas to the familiar can sometimes act as impediments to further learning.

Commitment: Some alternative ideas are little more than passing fancies, something imagined up and readily forgotten. Others are matters of great commitment. (So rejecting evolution may be tied to personal values and identity – see Chapter 11.) Range: Some alternative conceptions are about something quite specific – such as the earth is nearest the sun in summer or that the side of the moon facing away from the earth is its dark side. Others, sometimes called ‘alternative frameworks’, have extended ranges of application. The impetus framework may be applied to any situation where objects are moving; the octet framework is applied not only to different kinds of chemical bonding but also in thinking about why reactions happen, which chemical species are stable, patterns of ionisation energies etc. (Taber, 2013b). Embeddedness: Some alternative conceptions are little more than isolated ‘wrong facts’. Other alternative conceptions may be integrated into extended frameworks of ideas. For example, some students believe that separating a sodium atom from its outermost electron creates a lower-energy state, an idea which is premised on the principle that species with full outer shells are more stable, and so the specific conception is part of the more extensive alternative octet framework. Multiplicity: Some conceptions students present are the only viable option they are considering – but they may hold manifold conceptions. A student who is committed to the idea that species are inherently unchangeable will not consider an alternative. However, a student

The Nature of Students’ Scientific Knowledge could display both Darwinian and Lamarckian ideas about evolution, and so offer inconsistent explanations when presented with different examples. Research shows that students may switch between F–v and F–a thinking (see above) depending upon the contexts of a question (Palmer, 1997). A student learning advanced chemistry was able to explain the same explanandum in three alternative ways and considered these explanations complementary (Taber, 1998), where from a scientific perspective, two of these were complementary, but the third was an alternative conception. Frequency: Ideas like the impetus framework (F–v thinking) and the octet framework have been found to be very common among diverse groups of students, even though they seem to have somewhat different origins (the former largely due to intuitive knowledge, the latter largely based on interpreting formal teaching). Students share much in common in terms of their biology, their physical environment, the cultures they are immersed in and the institutional structures (such as those of the curriculum) where learning takes place. However, every individual has a somewhat unique experience of the world, and as learning is an incremental and iterative process of interpreting new experience in terms of existing understanding, they will develop their own system of conceptions or personal constructs. Some of these conceptions may be met infrequently by teachers and will seem idiosyncratic. Teachers can prepare themselves to better understand student thinking, and how it may influence their learning in class, by familiarising themselves with reviews of the common alternative conceptions that have been identified in particular topics. This is extremely useful, although it cannot cover every single alternative conception that students might construct.

Diagnostic assessment A distinction which has been much emphasised in recent years is that between summative assessment and formative assessment. Summative assessments are carried out at the end of schooling, or of a course or of a topic to see how much of the intended learning has occurred. (Unless there is a pretest used, this does not demonstrate whether the attainment measured reflects actual learning during the period of teaching; and even a pretest does not rule out that the learning may be largely due to other experiences, such as working with a personal tutor.) Whilst summative assessments fulfil a purpose that most people acknowledge (recognising attainment, a basis for selection for further courses, careers), it has been argued that formative assessment, assessment to inform teaching and learning, is more valuable for the teacher. In that sense, diagnostic assessment can be considered to be part of formative assessment. Diagnostic testing is used to find out about the current stage of student thinking, and it has become widely used in science education in terms of identifying common alternative conceptions. There are pre-existing resources that teachers can use to see if their students apply the thought patterns associated with common alternative conceptions – although one should always be aware that, in some topics, students may readily hold a range of alternative ways

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MasterClass in Science Education of thinking, and a response that reflects either an alternative or scientific conception does not imply that a student only thinks that way about the topic. In some topics, researchers have developed instruments to diagnose all commonly reported alternative conceptions, or to test whether students apply conceptions across a range of contexts. These are sometimes referred to as ‘inventories’ – the best known being the force concept inventory (Savinainen & Scott, 2002). Formative assessment should be ongoing during a course or topic. Much of it is informal, and is based on the teacher using dialogue in the classroom to check what students think and understand (see Chapter 8). Diagnostic assessment is usually carried out at the start of a course or topic. Although it may be something that students may initially feel is a little odd (or even unfair) if the rationale is not explained to them, it actually makes good sense to test a class before you teach them a topic.

Using a pretest as part of good teaching practice A good pretest has at least four deliberate functions, as well as a useful likely side effect. Giving students a carefully crafted test at the start of a project can: a)  act as a benchmark (to evaluate later progress); b)  check for expected prerequisite learning; c)  look for compacting opportunities; d)  identify the incidence of alternative conceptions; e)  orientate the learners to the topic.

An important ethical point here is that asking students to spend any substantive time and effort on an assessment where the teacher confidently expects most of the students will struggle to answer most of the questions is not acceptable. A good assessment is designed to be a learning opportunity (at least including an opportunity to review material previously learnt), so although including some questions you expect students will not be able to tackle, i.e. relating to function (c), is important, these should not dominate the experience for the students. The first function helps the teacher interpret any subsequent summative test. If some of the questions on the pretest are designed to be equivalent to some of those on the post-test (end of topic test), then a comparison of responses to these questions offers a measure of learning. If students get on average 60 per cent on these questions on the post-test, we may be unsure how good that is. If we can compare with a mean score of 52 per cent on comparable questions on the pretest (or more worrying, 65 per cent), then we might feel there had been limited progression in learning. However, had the students managed on average to only score 15 per cent on the relevant questions on the pretest, we might be much more satisfied with our teaching (even if the idealist in us wants all of the students to score 100 per cent on the post-test).

The Nature of Students’ Scientific Knowledge The second and third functions support the teacher in planning, and in particular in honing their lessons for this class of students. As part of preparing to teach a topic, a teacher needs to decide where to start. As was discussed in Chapter 5, effective teaching is based on a conceptual analysis of subject matter. This enables us to decide what the prerequisite knowledge is for the concepts and ideas we are hoping to teach. We cannot teach a scientific model of metallic conduction to students who do not have a notion of the structure of matter at submicroscopic scales; we cannot teach about orbital overlap in benzene to students who know only a ‘shell’ model of atomic structure; we cannot effectively teach about cellular respiration to students who have not been taught about cells. Having established the prerequisite knowledge for the teaching we intend to do, we should check it is available; otherwise, we need to teach this material before we proceed. The curriculum may tell us what students should have been taught, but topics can get missed, and in any case, ‘having been taught’ is not the same as ‘having learnt’. Just as our teaching plan assumes students already know some things, it equally assumes they do not know others. The common student cry of ‘Miss (or Sir), we’ve done this’ is not always helpful – especially with the spiral curriculum (see Chapters 4 and 5). Yet it is not impossible with some classes that at least some students have already progressed beyond where the curriculum suggests they should be. If students already show strong subject knowledge relating to some of what you intended to teach, it is not sensible to just teach it as you had intended regardless. This is unlikely to mean ignoring this material, but it may mean you are able to condense what had been two lessons in your initial plan into half of one lesson, and that it would be sensible to use some less familiar examples and applications to reinforce existing learning without making things too repetitive for students, and to focus more on tasks requiring higher-level skills (application, criticism/evaluation, synthesis). This ‘curriculum compaction’ allows more time for other parts of the topic (perhaps those where expected prerequisite knowledge was limited, or where there is a high incidence of alternative conceptions) or may free up some time to add a more creative synoptic revision activity for students before the final test. It is unlikely a teacher will not find a good use for such bonus time. There is a key moral imperative here: the teacher should never knowingly waste students’ time, for example, by asking them to do work which has no genuine value to their learning. Classroom activities need to be educative – that is, to offer a level of challenge from which all students can learn. This is a theme developed further in Chapter 15. If students in the class are found to have high incidences of common alternative conceptions, then finding time to explore their ideas in the context of the scientific accounts may be indicated. Discussion, demonstrations, group practical work and even thought experiments may prove useful. If some open-ended diagnostic questions are used, it may be possible to identify more idiosyncratic alternative conceptions that students hold as well those common ones that are well documented. It is important to recall that the purpose of this kind of assessment is to obtain useful information, so such questions can be seen as research probes

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MasterClass in Science Education to offer data for analysis, rather than test questions that need to be scored or marked correct or incorrect. As well as these specific purposes, a pretest can help act as an orientating activity for the new topic, giving students a flavour of the teaching to come. This links to the notion of an advance organiser – a tool suggested by the educational psychologist David Ausubel as something presented ahead of the specific teaching to help students link what is to be taught with aspects of prior learning and experience (Kember, 1991). A pretest can act as a type of scaffolding tool referred to as a scaffolding platform PLANK (platform for new knowledge) used to elicit relevant prior learning and organise it in a way most useful to support the intended new learning. When diagnostic assessment is considered in this way, it can be seen to be part of the overall toolkit used by the effective teacher to plan their teaching and hone it for a particular class. This theme of effective teaching is developed in Chapter 7.

Suggested further reading Driver, R., Rushworth, P., Squires, A., & Wood-Robinson, V. (2013). Making Sense of Secondary Science: Research into Children’s Ideas (2nd ed.). New York: Routledge. Taber, K. S. (2014). Student Thinking and Learning in Science: Perspectives on the Nature and Development of Learners’ Ideas. New York: Routledge.

Recognising Productive Lesson Activities

Chapter outline Analysing teaching Productive teaching activities Direct instruction, unguided discovery and a balanced approach to science teaching The notion of scaffolding and educative classroom activities Teacher choices that scaffold learning Suggested further reading

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Analysing teaching This chapter considers effective teaching and significant learning. Teaching is understood here as activity intended to bring about learning (see Chapter 4), and on that basis, productive lesson activities will be those that lead to intended learning. Assessment of learning is therefore an important aspect of effective teaching. This chapter will consider some of the ideas that research has suggested are important in planning teaching. It is also assumed in this chapter that teaching can be understood as comprising sequences of somewhat discrete (but linked) moves. A teaching move might be to introduce a new technical term, or to present a diagram to illustrate a point, or to offer an analogy for some technical concept from everyday life. Teaching can (and should) be planned but cannot sensibly be tightly scripted (see Figure 7.1). It may sometimes be sensible to add, drop or substitute moves during the lesson: for example, to pause a class practical activity to  remind students of a safety rule, or when explaining a concept to offer an

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MasterClass in Science Education additional example if the first used does not seem to be familiar to students. This is especially so when we seek to make teaching ‘dialogic’; that is, a kind of conversation that engages students actively, rather than as passive learners.

Figure 7.1  Much of the work of the teacher is subject to external constraints, or involves real-time honing according to the responses of our students, so the lesson plan is the key focus for a teacher’s creativity and professional expression.

Enquiry into practice: Analysing teaching Record some of your own teaching, or observe a colleague or locate a recording of science teaching from the internet. Explore how easy it is to analyse teaching (e.g. using a form like that in Table 7.1), according to the model suggested here, into a series of episodes based on discrete teaching/learning activities, and within that to identify sequences of teaching moves. Consider: Is there a clear logical sequence to how teaching moves follow on from each other? Reflect on: To what extent can teaching moves be planned in advance, and when must they be improvised in response to the teacher’s ongoing assessment of the learning occurring? If you have been observing a colleague, try to have a conversation about your observations and see if your colleague’s perceptions of their real-time teaching decisions reflect your interpretations as an observer. (You may find it most productive to work with a colleague who will reciprocate in observing and discussing your teaching.)

Recognising Productive Lesson Activities Table 7.1  Observing and analysing teaching Activity

Teaching move

Notes

Productive teaching activities A starting point in considering which teaching activities are productive might be to ask about an imaginary lesson where a class of students are sitting quietly in their seats, apparently watching and listening to a teacher presenting some scientific topic. The teacher talks, offers some diagrams and other graphics, and perhaps carries out a demonstration whilst simultaneously giving a running commentary, and the students make some notes. Is this a productive lesson? The scenario clearly has some positive aspects. As the students are orderly and quiet, there is no disruption to interfere with those who want to learn. Does this mean learning will occur?

Conditions for learning The considerations presented in earlier chapters suggest that we cannot know for sure from the limited information given above. It is certainly possible for intended learning to have occurred if we can assume that: a) the teacher has strong subject knowledge; b) the teacher has pitched the lesson at an appropriate level; c)   the teacher has sequenced the lesson in a logical order, with an engaging narrative; d) the teacher breaks the intended learning down into manageable chunks (‘learning quanta’); e) the teacher is able to use examples, analogies, metaphors, similes and so forth that link the subject matter to the students’ interests and experiences; f)   the teacher uses intonation, emphasis, gesture, modelling etc. to support communication; g) the students are motivated to learn, and are relatively comfortable physically and are not emotionally disturbed (scared, worried, overstressed etc.); h) the students have sufficient background knowledge to understand the presentation; i)  the students have reached a sufficient level of cognitive development to cope with the abstract nature of any theoretical content; j)   the students have sufficient metacognitive skills to appreciate that they need to make sense of the information being offered, and to monitor their own levels of comprehension of what they are being taught; k) the students have a sufficiently long concentration span to maintain engagement through the duration of the teaching episode.

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MasterClass in Science Education Perhaps there are other conditions missed out here, but this seems enough to remind us that teaching does not unproblematically and necessarily lead to learning. Clearly, it is in principle possible that these conditions will be met, and in practice these conditions will be sufficiently met sometimes, at least for large parts of a lesson, for most of the students in the class, for (some) intended learning to occur. Yet, there is clearly also much potential for things to go wrong here. If we consider this imaginary teaching–learning episode as a system (as a complex entity with many interacting features), then it relies upon a good deal of matching between the component parts. Consider the challenge of trying to build a functioning car engine from a complete set of parts – but ordered for a range of models from various manufacturers. The successful lesson depends upon the coordinated activity of a roomful of people, but where usually only the teacher has a detailed appreciation of the purpose, intended end points and plan. This might be compared with a symphony orchestra where only the conductor has a copy of the score of the music to be played. Teaching is a challenging activity.

The role of imagination in planning teaching In making decisions about a presentation, the teacher makes assumptions (either deliberately with reflection or implicitly through what is taken for granted) about what the students know; their characteristics as learners; the examples they will be familiar with; the experiences and interests they will have available to act as source domains for helpful metaphors and analogies; and so on. (I wonder how many readers have tried building car engines, or conducting an orchestra. If you have not, what mental resources did you bring to bear in making sense of these similes?) In effect, the teacher has what we might call a mental model of the students’ available resources for supporting learning. That model can feed into a mental simulation of how teaching may proceed, imagining the sense that students will make of possible teaching moves (Taber, 2014). Considering that a schoolteacher typically works with a range of classes, each of a large number of individual learners, this seems to rely upon the teacher having an extensive knowledge of the different students in the various classes they teach. To a large extent, this challenge is mediated by incorporating interaction within teacher presentations; the good teacher does not simply stand at the front of class and talk, but is constantly monitoring the expressions and body language of students, and intersperses the presentation with questions to the students. Indeed it has been noted that an aspect of the classroom context that becomes taken for granted is that teachers spend a lot of time asking questions they already know answers to (Edwards & Mercer, 1987). In another context, this might seem rather strange behaviour. If you were at a bus stop and someone else waiting there asked you what time the bus was due, you would likely assume they did not already know. What would you think (and how might you feel) if the reaction to your response ‘18.45’ was ‘yes, that’s right, well done’ or, perhaps speaking to the queue

Recognising Productive Lesson Activities in general, ‘excellent, there’s someone here who has done their homework’? However, a great deal of teacher-led classroom talk takes the triadic form of initiation–response–evaluation (IRE). In this way, the presentation is constantly refined in situ, as the teacher tests and modifies a mental model of the students (what they understand, available background knowledge, relevant experiences etc.) ‘online’ as they teach. This is one aspect of using formative assessment – assessing student knowledge and understanding during learning – to inform teaching.

Student diversity Yet there is a major complication here: most classes are wildly heterogeneous. Even when classes are banded (so supposedly a class comprises students of similar levels of ability) or set (so supposedly a class comprises students of similar levels of prior achievement in the subject area), every student brings their own unique qualities: their own idiosyncratic set of past experiences, knowledge strengths and gaps, personal alternative conceptions of topics and so forth. There are clear limitations on how even the most skilled communicator can present a topic in a way that it is understood as meaningful and offers educative value to a diverse audience – even when the students are all classed as ‘year 9, set 3’. Just considering a notion like intelligence (say as measured through standard IQ tests), we would expect any year cohort, such as 14- to 15-year-olds, to be distributed along a distribution somewhat like a Gaussian (normal) distribution – a bell curve. At either end of such a distribution there are low frequencies – so ‘top’ or ‘bottom’ sets determined by such a distribution will have wide ranges. Student achievement is in part a function of factors relating to motivation and not just something that might be called ‘ability’. So middle (‘ability’) sets are potentially likely to include some very able students who make minimal effort, alongside students who find the work very challenging but are highly conscientious in keeping up. One way to ensure all students follow the teacher’s presentation is to pitch it to the lowest achievers. Then everyone in the class should understand. Yet learners in a class all have the right to expect lessons to be educative; that is, to offer productive learning opportunities. A presentation pitched so that it can be readily understood by everyone in a class may offer few opportunities for learning for some of the students (see Chapter 15), so teachers will need to differentiate between different groups of learners in the same class. This may be difficult to achieve through a lesson that is largely a teacher-led presentation. Yet there is a common strand in guidance on pedagogy which argues that ‘direct instruction’ is often the best way to teach (Klahr, 2009), and most of us who enjoy teaching find the time flies when we are explaining science. For the teacher, this may be a ‘flow’ experience where we are deeply engaged (Csikszentmihalyi, 1997). Sometimes when time is passing quickly for the teacher who is dominating the classroom discourse, it may be experienced by many students as dragging – especially if they have lost the thread of the narrative, or zoned out when their concentration span was exceeded (only to find that the argument had moved on when they became aware of not paying attention and zoned back in).

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MasterClass in Science Education There are two conclusions here then. Firstly, that although teacher presentation of subject matter certainly has an important place in science teaching, with many students (and especially younger students), this is effective only in short bursts, and then only when there is a level of interactivity such that the teacher is constantly monitoring students’ interpretations of teaching and responding (changing pace, rephrasing, offering alternative examples etc.). Secondly, that students are diverse, and so teaching needs to be differentiated, which can be difficult when a teacher is presenting to a whole class (Kerry & Kerry, 1997). Some teachers are engaging, entertaining and inspirational communicators of their subject, and their whole-class teaching can be an important element of science pedagogy. However, effective differentiation is likely to be possible only when such whole-class presentations are complemented by, and interspersed with, other lesson activities.

Direct instruction, unguided discovery and a balanced approach to science teaching Although there have been claims that direct instruction is the most effective approach to teaching, unfortunately the term ‘direct instruction’ is used to mean different things, sometimes relating to very particular strategies, sometimes used vaguely to mean classrooms that appear largely teacher-centred. In order to understand what is often meant by ‘direct instruction’, we need to consider what it is being compared to. There has been an active debate in the United States (Tobias & Duffy, 2009), where direct instruction has been claimed to be superior to a range of alternatives with labels such as ‘student-centred learning’, ‘constructivist teaching’, ‘enquiry’ (or in the US, ‘inquiry’) ‘learning’, ‘discovery learning’, and ‘progressive education’ (Kirschner, Sweller & Clark, 2006). However, it is not clear whether these other approaches are a coherent set of pedagogies which can be clumped together as if they share some core qualities. Rather, this collective includes a range of approaches based on different starting points. There are educational theorists who have made arguments such as: L earners should follow their own interests, and learn topics only when they are ready to engage with them. zz The most powerful learning is based on what the child can discover for themselves, and so learners should be allowed to find things out for themselves rather than be presented with preformed knowledge. zz

Such ideas are not without merit, but taken to extreme this would involve classes where various pupils were working on completely different topics (and some none at all), and being left to find things out entirely for themselves. It could be argued that we would not need to invest in a school system if that is the kind of education we want. It is hard to imagine an education system that could manage to make such an approach work.

Recognising Productive Lesson Activities That said, Summerhill is a real school (in Suffolk, UK) that was set up as a ‘free school’ where a curriculum was offered but it was left entirely up to the pupils if and when they wished to take advantage of it by going to lessons (Aubrey & Riley, 2017). (I should point out that the UK Government’s policy to encourage more ‘free’ schools did not envisage this kind of freedom for the students from the curriculum, but rather envisaged freedom of the school administration from the oversight of democratically elected local authorities. Unhelpfully, we find in education that some of the key terms that appear in policy claims – ‘constructivist teaching’, ‘direct instruction’, ‘free schools’ – actually mean very different things to different people.) In most school systems, the best teachers can realistically do is to seek to offer students as much choice as possible within the existing constraints of timetables, the curriculum, options in examination specifications, and all the rest.

The role of imagination in learning The idea of learning by discovery is an important one. It is often more powerful to learn something by discovering it through our own experiences than it is to simply be told about it. There is a sense in which there always has to be a kind of discovery process (even if only internally, mentally, an act of imagination) to understand an abstract concept; otherwise, we just have rote learning of a form of words that, if recalled later, can be reproduced as evidence of (trivial) learning. A student can learn that ‘when a body exerts a force on another body, that other body always exerts a force back on the first body which is exactly as large, but directed back in the opposite direction’ as a form of words, but making sense of what that means and so being able to apply it correctly requires a form of discovery. There are laboratory set-ups which can illustrate such a principle, but most learners will not unproblematically discover such principles for themselves from unstructured laboratory work (Driver, 1983). In this case, working on a series of examples and talking them through may be more effective. For example, when a fly collides with the windscreen of a car, the fly will apply just as much force on the car as vice versa. A student who can explain that, and what the implications are (for the fly and the car), has likely ‘discovered’ the principle. They will have made the discovery in the context of some teaching, probably in terms of carefully planned teaching which has led them through an argument structured to help them towards the discovery. (An example concerning the abstract concept of a couple is discussed later in this chapter.) So this is a guided discovery process, quite different from just letting students get on with finding things out for themselves. There are clearly issues of context and degree here. We would not want any student to find out for themselves that alkali splashes in the eye are painful and dangerous. There are times when a fairly open-ended discovery process is desirable; times when it makes sense simply to provide information directly; and much scope in between where we want students to have a particular insight, but know that is likely only if there is a good deal of setting up the conditions needed for the discovery.

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Learning by enquiry Another commonly used term is ‘enquiry learning’. Science is an enquiry process (see Chapter 14), and an authentic science education therefore requires students to experience authentic enquiry. Sometimes the teacher’s lesson aim is to give the students experience of enquiry. The key focus then is on scientific processes, not on particular subject knowledge to be learnt. In this situation, it is less important if the enquiry leads to ‘right answers’ as the enquiry questions are only vehicles for learning enquiry processes. Indeed, given that science tends to require intense activity over extended periods of time (most scientists do not complete a study in a couple of hour sessions sandwiched around doing history, maths etc.), it would be irresponsible to suggest that effective scientific enquiry is simple and straightforward, and easily provides adequate answers (see Chapter 9). However, a science class that was based entirely on authentic enquiry activities would have to seriously compromise on the range of science to be considered. Realistically we do want students to experience enquiry, but we also want them to meet key scientific ideas across a whole range of topics. What the best balance is here is a matter for debate and may not be the same for all groups of students. Criticism of discovery learning has sometimes targeted an extreme situation where teaching science by enquiry means that the teacher does not actually provide any scientific knowledge but rather expects students to find things out through their own unguided enquiry. It has even been suggested that the teacher does not actually need to know any science, as their role is simply to facilitate the student activity through which students will make discoveries. Supposedly, this state of affairs has actually existed in some middle schools in parts of the United States (Cromer, 1997). It may be helpful to reflect on our underlying purposes in asking all school students to study science (e.g. as discussed in Chapter 2). One can imagine an argument that, up to a certain age, students need to be immersed in the processes of enquiry, where this background will provide a strong context for later appreciating a (somewhat) different kind of science teaching. Learning about and through the processes of enquiry allows the nature of the science that is to be taught later to be appreciated – so scientific ideas are inherently understood as products of the evidential and discourse processes of science. School students often seem to have difficulty appreciating the status of the scientific ideas they meet in the curriculum as models, theories, perspectives etc. rather than as ‘facts’ and definitive accounts of the world ‘proved’ by science. A focus in the early years on learning science through activity, and in particular the dialectic between ideas and experiences, might well pay dividends later. Whether the critics of enquiry teaching were describing a real situation or exaggerating their target, it seems clear that deciding that we do not want all science lessons to be openended discovery is not the same as excluding enquiry and guided discovery as important components of effective science learning. Ideas about teaching enquiry within the science curriculum are explored further in Chapter 14.

Recognising Productive Lesson Activities

The notion of scaffolding and educative classroom activities Effective science teaching then is neither allowing completely open-ended discovery nor the telling of a catalogue of predigested facts, principles, theories etc., but rather needs to offer optimally guided support for learning (Taber, 2011a). So the key question then is how much structure teachers should provide for student learning activities. Learning the abstract ideas of science is challenging, and instruction needs to be carefully planned. That does not imply the teacher needs to plan a lecture where the expert (teacher) spends the whole time taking students carefully through the logical structure of the topic. That might work with mature and selected learners in a university setting (although that is by no means assured) but is insufficient for most learners. As will be appreciated from earlier chapters, effective learning of abstract conceptual material is hard won, and takes time. Careful teacher exposition is an important part of this, but needs to be a kind of pedagogic glue that holds together a series of learning activities for students. Those activities need to engage learners and help them internalise the individual components needed to build up an understanding of the scientific ideas. Here the ideas of Lev Vygotsky are very useful. Vygotsky worked in the early twentieth century in the Soviet Union and he was interested in learning and development. He took a broad view of human learning, considering that a full understanding encompassed the evolution of the human species, the historical development of the culture, the course of development of the individual and how individual psychological processes develop in the individual. Vygotsky (1978) recognised that there was a strong cultural and social element in learning.

An educational thought experiment We might consider how much of what we know we might have been able to have learnt if we had been born in complete isolation from the rest of society. We might consider a thought experiment where a baby girl is taken and somehow nursed and looked after by some machine – which provides for her immediate needs of food, shelter etc. but offers no direct or indirect contact with human culture. (We can even imagine the machine is alien technology.) The child might learn to crawl and walk, perhaps swim, perhaps even to laugh and cry. It would not read or talk, or know about the periodic table, circuit symbols or the names of cellular components, as these are all symbolic tools of culture and so somewhat arbitrary (the aliens probably have a version of the periodic table, their own circuit symbols and their own term for endoplasmic reticulum, but they do not share any of this with the child). Moreover, the child is unlikely to learn about the inverse square law of gravitation, the reactivity series of metals or even that cells exist and can be considered to have discrete

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MasterClass in Science Education components. These are not, however, cultural tools but aspects of nature. These are things that have been discovered by humans who are physiologically much like our isolated child. Yet, even if she grew healthily and lived to a ripe old age, she would be most unlikely to make any of these discoveries. She probably would not discover magnetism, neutralisation or photosynthesis, either. She lacks the tools to make such discoveries, tools that are available to real learners in our schools through our culture. Vygotsky would consider these tools to include artefacts (such as microscopes) but also symbolic tools such as language. Language likely evolved to help us communicate with each other. However, at some point, people found that once we had internalised language from those around us, we could use it privately to support our own thinking. We do not need verbal language to think, and not all of our thinking uses such language – but our thinking is much more powerful with it. We all understand pie charts, line graphs, fractions, chemical equations and cross-sectional diagrams – but few of us would have developed all these useful tools without support from others already having access to these cultural resources. Although actually carrying out the experiment described above would be unethical, our modern lives offer some strong evidence of the value of cultural tools. Human beings living 10,000 years ago were biologically no different to us; yet they did not have personal computers, or iPods, or wrist watches, or centrally heated homes, or high-speed trains, or ironfree shirts, or kidney dialysis machines or … (please add your own preferred examples). If a time machine could swap newly born children between these times (another thought experiment), these children would grow up and fit in their adopted cultures. What makes modern humans ‘modern’ is the ability of humans to learn from the existing culture so each generation is able to progress further, building on the one before. (Unfortunately, it is less clear whether cultural tools have allowed humans to become morally better than thousands of years ago; despite all our technological achievements, some people still cheat and lie, use violence to bring about political ends, bully and abuse the vulnerable, and torture those who they take objection to.)

Teacher choices that scaffold learning It should be clear that teaching involves a great many choices, both when one is planning lessons and when one is converting those plans into classroom practice. This will briefly be illustrated by one example. Consider the introduction of a new science concept, that of a couple. When I taught the concept of a couple (that is, where there are two forces, equal in magnitude, antiparallel in direction and acting along different lines of action), students who apparently grasped the meaning of the definition still took time to make good sense of the idea. They needed to engage with the idea through activities, which allowed them to ‘discover’ the concept – something more than just learning the definition as a form of words. Two possible activities are represented in Figures 7.2 and 7.3.

Recognising Productive Lesson Activities

Figure 7.2  Spot the couples: Applying the definition as a learning activity.

Figure 7.3  What do we discover by calculating the turning effects of these pairs of forces?

Figure 7.2 offers a series of diagrams that may, or may not, represent couples. A physics teacher who is very familiar with the kind of abstract representation used here (see also Figure 3.2), and who long ago internalised the concept ‘couple’, can probably see at once which diagrams represent couples and why the others do not. The task is less trivial for most learners just meeting the idea. Given this basic task, there are choices to be made about how many examples are needed, and how complex we might make them. A teacher also has choices about whether to ask students to complete the task individually (perhaps in silence) or in conversations as pairs or

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MasterClass in Science Education small groups, or whether to simply work with the whole class and call upon students to comment on particular examples. Deciding how to proceed may partly depend upon the class – for example, the teacher may judge that students in some classes will get the ideas (internally ‘discover’ the principle) readily when discussing the examples with the class, whereas more time will be needed with other groups, so the teacher reviews the examples with the class only after the students have had some time to discuss them in pairs. Many students feel that school science is a series of abstract ideas they are asked to learn for their own sake. Learning about couples could certainly seem to fit that complaint. Figure 7.3 suggests a further learning activity. This time, the students are set up to discover a key point about couples, which justifies why we need a specific concept and label for this particular arrangement of forces. The same kind of teaching decisions arise, but also this time the issue of the precise difficulty of the examples may be more critical. This may be a case where differentiation will offer more individualised support, perhaps offering more ‘scaffolding’, to some students than others.

Figure 7.4  An introductory task to review prerequisite learning (for the activity illustrated in Figure 7.3).

Recognising Productive Lesson Activities

Moves to scaffold student learning Some students can readily and successfully tackle the task as presented in Figure 7.3. Others may need some hints (e.g. assume the bar is 3 m long, and the larger forces are 2 N). Others may need distances and force magnitudes clearly labelled on the diagrams to help them manage the task within working memory. Alternatively, organising students to work in groups may be sufficient if the composition of the groups provides a more advanced peer to support the learning of others (see Chapter 15). One type of scaffolding tool a teacher may introduce has a role akin to the ‘advance organiser’ suggested by Ausubel (see Chapter 6). It may be helpful for some students to preface an activity by helping them bring to mind and review prerequisite learning needed in the main activity. Such a scaffolding ‘PLANK’ (platform for new learning) is intended to offer a lowchallenge task that orientates learners to the main activity (see Figure 7.4). An activity can be scaffolded by offering hints, detailed instructions or worked examples which allow students to successfully complete an activity they could not initially manage due

Figure 7.5  Some options for scaffolding the learning activity presented in Figure 7.3.

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MasterClass in Science Education to the novelty of the activity (see Figure 7.5). Such scaffolding ‘POLES’ (provided outlines lending epistemological support) are dismantled, or ‘faded’, as the learner develops competence in an activity.

Suggested further reading Hammer, D. (1997). Discovery learning and discovery teaching. Cognition and Instruction, 15(4), 485–529. Newton, D. P. (2000). Teaching for Understanding: What It Is and How to Do It. London: RoutledgeFalmer.

Seeking Evidence of Significant Learning

Chapter outline Recognising significant learning Dialogic teaching Enquiring into the factors influencing learning outcomes Scientific research in education Suggested further reading

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Recognising significant learning If teaching is an activity intended to bring about learning, then we can evaluate its effectiveness only by having some measure of the extent to which intended learning has occurred. This implies undertaking some kind of assessment – although that does not need to imply a formal test. When considering how we might assess learning, it is useful to draw upon several ideas met in earlier chapters of this book. Chapter 2 explored the place of science in the school curriculum, and in particular, the purposes of education that might set out overarching aims for science education. Perhaps part of what we are trying to do is support students in learning specific science knowledge, in which case that is what we will assess. However, it very likely that this will be only one aspect of what we are trying to achieve. It is important to be wary of a tendency to test those things that are relatively easy to test (list the first twenty chemical elements with their approximate atomic masses; name as many animal phyla as you can recall). It is more difficult to assess in-depth understanding or higher-level cognitive skills.

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Figure 8.1  There is a general tendency that those things that are easier to assess objectively relate to lower-level educational objectives.

We can easily become overconcerned with accurate and precise marking (see Figure 8.1). Assessment becomes more subjective the more demanding the kind of learning being assessed. It is not cynicism that leads to the advice to doctoral students to write their thesis with their specific examiners in mind! A useful aphorism is that what can be measured most precisely is not necessarily what is most important to measure. Where it is sensible to set some kind of formal test at the end of a topic, it is important to bear in mind the point made in Chapter 5 about diagnostic assessment. A post-test does not tell us anything about what has been learnt unless we have a useful pretest with which to compare it. It may seem impressive that after spending three weeks teaching electromagnetism, the average class score was 78 per cent – but less so if the average score on a set of comparable questions three weeks previously was 72 per cent. We would look to see a substantive shift in average score between a pretest and a post-test as evidence of student progress. We should even then bear in mind that learning tends to be a process extended in time (see Chapter 5), which is why, in research, pretest scores may be compared with scores on a deferred post-test that students undertake some weeks or even months after teaching of the topic is complete. In research, there is a complication that an improvement from a pretest to a post-test cannot be considered sufficient evidence of effective teaching as the pretest may itself have contributed to learning: simply undertaking the pretest, thinking about the questions and

Seeking Evidence of Significant Learning considering possible answers could in principle be a learning experience that might be reflected in a later test. (This may be countered in research by employing a suitable control or comparison group who also take the pretest and post-test, without also experiencing the learning activities in between. The problems of matching groups to find a suitable control will be clear from comments later in the chapter.) In research then, the potential of a pretest to support learning may be an inconvenience. In teaching, however, wherever possible, we should set up assessments to provide learning opportunities. Indeed, ideally, we should evaluate learning by observing students in normal classroom activities. One leading theorist who featured in the previous chapter, Vygotsky (1978), would likely consider such assessment much more valid than the more clinical setting of a formal test. Vygotsky considered that productive learning occurred in what he described as the zone of proximal development, or ZPD (see Chapter 15), and this happened when the learner was working on a challenging task with support to help them move beyond what they could currently manage alone. Vygotsky considered that assessing a student working in the ZPD was much more informative than a traditional formal test. Giving that education should prepare young people for adult life, where, even in work contexts, they are seldom asked to complete a task alone without accessing any kind of support, this seems a very valid point.

Dialogic teaching One approach to teaching in a way that engages children, and which offers inherent opportunities for formative assessment, is called ‘dialogic teaching’ (Scott, 1998). This means teaching that encompasses multiple voices or views. This is contrasted with authoritative teaching, which presents only one voice or perspective – the right one! Dialogic teaching is not intended to be restricted to episodes where there are no canonical answers (e.g. Should we build more nuclear power stations? Should people have to opt out of becoming organ donors?) but also applies when teaching topics such as Newton’s laws of motion, factors influencing rates of reactions, or respiration in plants. However, it is very important to note (see Figure 3.1) that this approach is not premised on some relativist notion, or laissez-faire thinking. The scientific principle at work here is that people should come to adopt scientific ways of conceptualising the world because they are persuaded of the value of those ideas by evidence and argument. The educational principle at work is that we are more likely to shift a learner’s thinking fundamentally if we engage with it and get them to compare their own ideas with those being presented in science – rather than simply asking them to accept and learn something which does not fit their existing intuitions and understanding. This reflects the way science itself works. Currently accepted scientific ideas are the present stage of development of an ongoing dialogue – undertaken through informal contacts between scientists, through conference and similar presentations, through the reviewing process when one is submitting manuscripts to journals, and finally through conversations

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MasterClass in Science Education in the scientific literature where new articles cite, build upon, and respond to (and sometimes challenge) existing literature. It sometimes takes years for scientists to shift their thinking and change their minds, so we can hardly expect students to simply abandon their existing thinking because we tell them we know better. Even if they wanted to oblige us, the human brain does not usually facilitate such ready shifts in thinking (see Chapter 5). Dialogic teaching is not then an invitation to the chaos of all views being presented and accepted as correct or equally viable. Rather it is a process of persuading students through comparing the available suggestions and illustrating the merits of scientific ideas through evidence, demonstrations, arguments, experiments and so forth. This acknowledges that there is not usually a conceptual vacuum into which to offer canonical ideas, so persuading students usually depends upon them making explicit their own thinking, so to compare, contrast and evaluate their thinking against the ideas being presented in teaching. When this is not done, it is likely learners will soon forget the novel ideas, or come to misunderstand them in the light of their own thinking, or – without realising they are doing so – hybridise the two sets of ideas (Gilbert, Osborne & Fensham, 1982). The multiple voices of dialogic teaching may at times be represented by one person: the teacher may take up and explore different ideas from different students within the class; a student may be asked to summarise the different views that have been put forward, or to compare them on some feature (see Figure 8.2). However, the dialogic approach does require elicitation of the pool of current ideas being considered, and so different students

Figure 8.2  A hypothetical lesson structure, where the teacher shifts between exploring different ideas and developing the canonical scientific account, and between working with the whole class and supporting working in groups. (Based on the ideas of Mortimer & Scott, 2003.)

Seeking Evidence of Significant Learning must contribute at points in the process. This could be in teacher-led class discussion; it could be by completing diagnostic assessment items at the start of a topic; it could be through the teacher eavesdropping as small groups work on an activity such as discussing a concept cartoon (Keogh & Stuart, 1999) or exploring a thought experiment. Dialogic teaching therefore seeks to elicit students’ own ideas, explore their implications, test them out and so forth as part of a process of suggesting why scientists have offered the accounts they have. The aim is not to get students to believe that the scientific ideas are ‘true’ (see Chapter 10) but to appreciate why scientists have adopted them as our current best ways of thinking about a topic. This means that the teacher certainly does teach the science (especially where no student puts forward canonical ideas), but designs lesson sequences that move between dialogic episodes and time spent focusing on the canonical accounts set out in curriculum (Scott, 1998). Orchestrating this is challenging, and can be only planned in outline, as the teacher needs to use feedback from the class to indicate when to move on or modify the lesson plan (see Figure 7.1).

Formative assessment during teaching So, the teacher needs to be able to identify when there is significant learning, and not just at the end of a topic, but at key points during a lesson. Dialogic teaching allows this because it provides ongoing opportunities for students to talk about their developing ideas and understanding, and so for formative assessment by the teacher (Taber, 2014).

Enquiry into practice: Meaningful formative assessment Record some of your teaching, including both whole-class elements and your conversations with individuals or groups. Analyse your utterances: zz

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Where do you ask questions or seek comments that provide information on student knowledge and understanding? What do you learn by listening in on students working (or informally viewing their work in progress)? How do you use such information to inform your immediate teaching moves (e.g. what you say in response)? Is there scope to develop your use of formative feedback to refine your decision-making during teaching?

If you identify scope for improving your practice, follow-up your use of these techniques over time, and in other teaching contexts. This type of exercise could also be useful in mentoring less-experienced colleagues, or for pairs/groups of teachers acting as critical friends.

As well as using formative feedback as part of the real-time decision-making in lessons, teachers can seek feedback from current students to inform refinements of future lesson plans. (Consider the hypothetical decisions involved in refining the ‘couples’ examples in

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MasterClass in Science Education Chapter 7.) Talking to students during or after a lesson can elicit their perceptions of whether work was too routine or too challenging; whether more, or less, time and/or examples might be indicated; whether a different kind of support or activity might have been more valuable. The professional teacher is aware of their privileged position in relation to greater subject knowledge, awareness of how an activity or lesson fits in a longer-term plan, and pedagogic knowledge. Therefore, a teacher does not negate their responsibility in view of student perceptions. However, the professional teacher also acknowledges the privileged position of the students in experiencing lessons and specific activities as learners, and seeks their views, the student voice (see Chapter 2), as part of the evidence for evaluating teaching and informing any modifications that might be considered next time a topic is taught. Enquiry into practice: Using feedback to evaluate teaching Record some of your teaching, including both whole-class elements and your conversations with individuals or groups. Analyse your utterances: zz

Do you ask questions or seek comments that provide information on the value and level of the learning activities included in lessons?

Focus on collecting such views, and considering how useful they might be in informing future teaching: zz

zz

Note any specific changes that might be indicated (these might be as basic as modifying a diagram, or resequencing examples). Pay particular attention to diversity of responses: does this suggest that more differentiation is needed to support those struggling or to challenge those who are further advanced (see Chapter 15), or to provide more variety for students with diverse interests/aspirations/learning styles?

Again, this type of exercise could also be useful in mentoring less-experienced colleagues, or for pairs/groups of teachers acting as critical friends.

Enquiring into the factors influencing learning outcomes A professional teacher will know there are many factors that determine learning outcomes, and these include aspects of student experience of the classroom. A well-established notion is Maslow’s (1948) hierarchy of needs which reminds us that students are unlikely to learn well if they come to class hungry, overtired, scared, feeling unloved etc. These are matters that relate mainly to out-of-school experience, and teachers have limited control over them. A teacher’s expertise is in education, but all teachers should be alert to signs that children may be having problems at home, as these may sometimes indicate the need to involve other agencies (such as social workers). Schools usually have a senior member of staff who has some specific training and liaises with other authorities when teachers suspect a student

Seeking Evidence of Significant Learning may be subject to some kind of abuse, including neglect, outside school. All teachers have responsibilities to pass on concerns if they suspect poor student behaviour or performance may indicate some such problem. Learners should not be nervous or overstressed in class, but neither so relaxed they are not focused. If students are engaged, they tend to learn more (although that is useful only if they are learning appropriate things of course). Classroom atmosphere is important. Classrooms need to be orderly, although some level of chaos may support creativity at times – and order need not be equated with a fetish for routines. Students do generally benefit from some routine – but too much routine can become boring. The human nervous system has developed to notice change and difference, and to largely filter out from consciousness whatever represents the status quo. Indeed, this relates to one of the potential threats to validity of educational research. To improve education, we need to innovate – to try out new ways of doing things. But such innovations need to be tested for their effectiveness in classrooms – especially when what they are to replace is considered to be generally working quite well. We can aspire to do much better than ‘generally quite well’, but there is also a lot of scope for doing worse if we make changes that prove to be counterproductive. So we need to evaluate new innovations against existing practice. In principle, that may sound quite straightforward: we are scientists, so can we do some kind of experimental test?

The shock of the new In practice, the very novelty of something different may in itself act as a factor in a number of ways that confound research studies. In terms of the learners, we can consider two possible, contrasting effects: a) Students who are reasonably successful and comfortable in the current regime may feel threatened by the new, e.g. ‘I do well in tests working alone, why would I want to be assessed as part of a group project where my grade may be influenced by others?’ b) Students who are frustrated or bored with current provision may (if perhaps only temporarily) respond to something different. If nothing else, their attention will be engaged, which is a prerequisite for effective learning.

Importantly, these responses do not relate to the qualities of the innovation, but relate simply to the extent that students perceive some difference in what is being presented or expected from them. So an innovation that is initially evaluated as effective may lose that level of effectiveness once it becomes regular practice if what has been measured is actually novelty value. One might even offer the hypothesis that a teacher working with a very bored and disengaged class could try teaching in a different silly hat each lesson (Easter bonnet, Napoleon, a miner, sea captain, Ladies’ Day at Ascot etc.). This will attract student attention (and likely

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MasterClass in Science Education comments) and could even lead to more learning – but clearly after a few weeks (assuming a sufficient supply of hats), the effect would decline.

Practising practice makes perfect Another important threat to the validity of research findings due to novelty relates to the teacher’s expertise. If a teacher is asked to teach a new topic, adopt a new approach etc., then they initially lack the fine-tuning of the approach that comes from having honed it across a range of classes (see Chapter 4 for a discussion of pedagogic content knowledge). Lack of familiarity, and perhaps confidence, will likely have a measurable effect, so comparing an innovation involving a teacher doing something new with routine practice by a teacher who has had experience of working with an existing approach is not a ‘fair’ test.

Expect to confirm your expectations Another major confounding issue is participants’ expectations. Drug trials (that is, tests of new medicines, not prosecutions of suspected criminals) use a double-blind procedure. Participants swallow a tablet (or have an injection, attach a patch to their skin etc.) that may contain the drug or may just be a placebo. Neither the participant nor the person administering the procedure knows whether the participant is in the treatment or control group. This arrangement is important because people’s beliefs, and so their expectations, are found to have a strong effect on outcomes. This will not be a surprise to anyone who knows about homeopathic medical cures. Many people believe in these medicines and claim they relieve their symptoms, even though the amount of active ingredient is so small there is no feasible potential for any effect. Often these active ingredients are salts that are found in the normal diet at levels that would totally swamp the doses used in homeopathic medicine. Some alternative therapies undoubtedly do work, even when this may have nothing to do with the supposed medicine (and seeking such therapies instead of consulting a medical doctor could be dangerous in the case of a serious problem, something that is a major issue in parts of India, for example). People visiting an alternative practitioner may start to feel they are taking control of the situation by taking action; their mood may be raised by the positive attitude and encouragement of the practitioner; the process of someone spending time focusing on their problems and paying attention to the patient in a relaxed atmosphere may be very therapeutic. The treatment may often be worth the cost, even if not for the reasons claimed by the therapist. Although there are charlatans, many such therapists deeply believe in their practice, which is likely part of the explanation of the outcomes. As they and their clients believe in the treatment, they expect positive outcomes. As humans have strong confirmation bias (Nickerson, 1998) and so give more credence to potential evidence for what we believe and expect, such therapies may well be effective, if sometimes expensive, placebos. Even when blood tests and

Seeking Evidence of Significant Learning scans suggest no changes in condition, the living experience of the patient may be much more positive. The same effects could be produced by a doctor with a good bedside manner, and time to spend talking to the patient – but not by a family doctor who has only a few minutes for a consultation and is mindful of a waiting room full of patients with overbooked appointments.

Expectations in education The same kind of effects happen in educational research. This was demonstrated when researchers reported having developed a test to identify students ready to make substantive progress in school. They wanted to test their instrument, so they visited a school and surveyed the children. They were then able to predict for the teachers which children would make the most progress in the following school year – the ‘growth spurters’ (Rosenthal & Jacobson, 1968). The children identified did indeed make significantly more progress on average than their classmates. This outcome was despite these children actually being selected at random, as the test did not really exist. Rosenthal and Jacobson’s study produced some valuable information, but this was possible only by their tricking the teachers by lying to them. This ‘experiment’ appears to have benefited some randomly chosen students relative to others. This raises the genuine question of whether it is acceptable to behave in such underhand ways in order to acquire research evidence. Nowadays, both teachers and professional researchers are expected to follow suitable codes of ethics (e.g. British Educational Research Association, 2018) which are much more demanding than the norms of half a century ago. Such codes offer clear principles, although their application to real research contexts may require careful judgements, especially when teachers research their own classrooms and so adopt the dual role of teacher and researcher (Taber, 2013a). It seems that some students made more progress than others because their teachers expected them to. Presumably there was mediation: the way teachers interpreted what these students did and said and so the ways they interacted with them were influenced by their beliefs that these children had particular potential. It is clearly not possible to do doubleblind trials to test teaching approaches and innovations: teachers and students are going to find it pretty obvious when they are in an experimental condition rather than in a control condition. It is therefore hard to see how teacher (and student) beliefs can be excluded from influencing such studies.

Pointless educational experiments? Many small-scale studies compare the same teacher teaching two classes the same topic in different ways, or two different teachers teaching the same topic by different means. To make a totally fair test, one would wish to match the classes, the classrooms, the time of day of the lessons, and so much more. When the different approaches are taught by different teachers, one would want these matched in terms of subject knowledge, pedagogic skills and so forth.

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MasterClass in Science Education This should include their level of belief in the effectiveness of the approach they are to use. If the same teacher teaches the topic in two different ways, we would want to be sure they had equal confidence in the potential effectiveness of both approaches, as well as the same level of skill in teaching in those ways. As this suggests, few small-scale experimental studies of teaching innovations are entirely convincing as it is seldom possible to measure, let alone match, many of the potentially important variables. This is why the ‘gold standard’ for educational research is often considered to be largescale randomised trials: by assigning teachers and classes randomly to the innovation or control condition, and by using a large enough sample of classes, one can use statistics to highlight any unlikely outcomes. Even in such studies, it is never the case that the result ‘proves’ one way of teaching is better: it can only show that there was a tendency to get better results in one approach that is unlikely to be due to chance. Where small-scale experiments are generally subject to threats to validity, large-scale randomised trials are expensive and extremely difficult to organise. In Chapter 13, some outcomes from one randomised trial are discussed where the variation of outcomes within each condition was much greater than the average difference between the two conditions. This is something else that large-scale studies have indicated: that even when one approach can be shown to work best on average across a large sample, it may still be less effective in some contexts, i.e. with some teachers working with some classes in some schools.

Scientific research in education This is all worth bearing in mind when one is planning research in school. Experimental research is potentially very powerful because it can apply statistics to look for important average differences. However, when one is working in a particular local context (when introducing innovations, for example), it may be better to undertake detailed case studies using qualitative methods to build a detailed picture of teaching and learning in the local context, rather than looking to undertake educational experiments when the requirements for any kind of genuine experiment are likely to be heavily compromised. Science teachers often enter teaching with a strong bias towards quantitative data and experimental research designs. Yet educational research often needs to be carried out in naturalistic settings where the phenomenon being studied is embedded in a complex context, and most relevant variables cannot be controlled even when there are valid and reliable instruments to measure them. A scientific approach to research is one that is realistic in considering what can be achieved, and matches appropriate methodology to research purposes and the phenomena studied (National Research Council Committee on Scientific Principles for Educational Research, 2002). Most teachers have privileged access to and knowledge of specific classrooms: they are able to look in detail at a very small and non-representative sample of classes. This makes research producing generalisable knowledge problematic, but also

Seeking Evidence of Significant Learning means that teachers are well placed to undertake context-directed research (Taber, 2013a) that looks to understand and improve their own professional context.

Suggested further reading Taber, K. S. (2014). Student Thinking and Learning in Science: Perspectives on the Nature and Development of Learners’ Ideas. New York: Routledge. Wragg, E. C. (2012). An Introduction to Classroom Observation (Classic ed.). Abingdon: Routledge.

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Part III Issues in Teaching Science Subjects

A Twenty-First Century Notion of Scientific Knowledge

Chapter outline Science seeks general knowledge Scientific knowledge is theoretical A core issue for science education Suggested further reading

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The scientific method is the most fallible means we have of developing reliable new knowledge – apart from all the other approaches that have been tried from time to time. (With apologies to Winston Churchill’s retelling of a view of democracy as a basis for government.)

Science seeks general knowledge This book has a strong focus on aspects of the nature of science, which is considered to be fundamental to science education because of our major aims for science teaching (see Chapter 2). One characteristic feature of natural science is that it is not primarily concerned with producing knowledge of specific cases and examples, but rather it seeks knowledge that is generalisable. This is less true in some other areas of scholarship. Some enquiries in areas such as history and biography are focused on individual cases for their own intrinsic interest. Even in these areas, the findings from one study might be used to illuminate others; however, finding out about the individual case in its own terms is the primary aim. The distinction between disciplines such as history and the natural sciences that seek to explore

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MasterClass in Science Education norms and general laws was highlighted long ago (Windelbrand, 1894/1980), and the two types of approach were labelled ‘nomothetic’ and ‘idiographic’. Interestingly, both types of enquiry were considered to potentially be scientific where they applied systematic methods suitable for the purposes of exploring particular research questions (see also Chapter 8), but ‘historical sciences’ required a different mentality to the natural sciences. Educational studies explore a wide range of different types of research question, and so nomothetic and idiographic approaches are both used, depending upon the aims of particular enquiries. Most commonly in natural sciences, we are observing, or intervening in, some specific phenomena using one or a small number of examples to represent a general type. For example, in school science, we might get students to heat some ice and measure the temperature at which it melts; to see what happens when some magnesium ribbon is added to some hydrochloric acid; to see which section of a choice chamber woodlice move to over time; or to see how the resistance of a piece of wire depends upon its length. The enquiry is undertaken with a particular sample of ice; some particular metal ribbon added to a particular beaker of acid; with some specific woodlice in a particular chamber; with wire cut from a particular reel. Yet actually we are not especially interested in that particular sample of ice, ribbon, acid, wire – or even those particular woodlice. The intention is to find out about ‘ice’, ‘magnesium and acid’, ‘woodlice’ and ‘metal wires’ as general classes of objects. For example, we might find that when we cut different lengths of wire from a particular reel, the amount of current that flows through the wire when subject to the same potential difference across its ends varies with length in a systematic manner. Within experimental error (the limits of our ability to measure precisely with the particular instrumental set-up), the resistance of a wire is directly proportional to its length. We might ask if we are justified in concluding that the resistance of metal wire (sic, in general) is directly proportional to length as (with our single example) that seems to be the pattern. What often happens in school science is that we seem to draw a general conclusion from such limited evidence. This may seem justified because the teacher ‘knows’ that this is the pattern being sought, and the students probably know too if they have been paying attention or have read their textbooks. Moreover, in this case, the conclusion will seem intuitive to many of the pupils: you have twice as much wire for the current to pass through, so it will be resisted twice as much. (Phrasing the conclusion in those terms may encourage such an intuition, whereas saying that ‘the ratio of current flow to potential difference is inversely proportional to the length of the wire’ might not appear as intuitive to most students.) However, these are considerations external to the available evidence. There is clearly room here to question the conclusion in terms of the actual evidence collected. Perhaps only four or five lengths of wire were tested: is that enough to be sure? Perhaps the samples were all cut from the reel in order of increasing length – could the result be more about the structure of this particular wire or the position on a reel from which a sample is cut rather than due to length? (Would the same results be found if we cut the lengths in a different order – or from further into the reel?) Would the same results be found

A Twenty-First Century Notion of Scientific Knowledge in a reel manufactured by a different company? If the metal had a different composition – if this wire is steel – would we get the same basic pattern for copper? For that matter, does the wire need to be of circular cross section? (What if we used our magnesium ribbon and cut that into different lengths?) We know (or at least, think we know) the answers to these questions of course, because we already know the scientific principles – but should a single trial under one set of conditions be enough here to convince students? In effect, many school practicals that are framed as experiments or enquiries are no such thing – they are demonstrations of well-established principles where the expected answers are clear, and anything different is usually seen as ‘getting the experiment wrong’. If a student’s data suggested that the resistance of a wire was independent of its length, or was inversely proportional to length or increased with length to the power of 1.7 etc., then we would likely dismiss the empirical evidence and explain it away as flawed experimentation, faulty equipment or poor record keeping. Yet ignoring the evidence because it does not fit our preconceptions is the very opposite of the scientific attitude. Science tells us to be wary of drawing conclusions from data too readily, but that does not mean dismissing inconvenient evidence. Imagine that our experiment with wires of different lengths had been done for the first time ever, then the results might have suggested that there was a pattern, with resistance increasing in proportion to wire length. That would have been a starting point for a programme of research that sought to test replicability of the original findings and test their range of application (does it apply to very long or very short wires, to wires of different crosssectional area, or different cross-sectional shape or different material compositions, and at different temperatures; does it apply if the wire is under tension etc.). There is a serious issue here of whether school practical work offers a taste of authentic scientific enquiry – this is a point returned to in Chapter 14. However, here we will focus more on the key point that science is not usually that concerned with what happens in specific situations – with particular events (this group of students testing wires of different length) or particular samples (this specific beaker of ice being heated in this particular classroom). Rather science looks to find general patterns and widely applicable (and ideally universal) principles that can be used to explain and predict in contexts well beyond their initial discovery.

How to test generalities: The problem of induction From a philosophical perspective, there is a challenge in testing general statements. Let us consider a simple example. Perhaps some pupils find that their sample of ice melted at 0°C. The teacher would be encouraged because according to the accepted texts, samples of pure water ice at atmospheric pressure melt at 0°C. That is not a statement about what was found to happen to some particular ice, but rather a general statement. It applies (supposedly) to all ice – all of the ice that exists on earth today, and also to all of the ice elsewhere in the solar system, or even in distant galaxies. It applies to all of the ice that existed in the past – in

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MasterClass in Science Education past ice ages for example, going back before human science, before human history, before hominids appeared on earth. It applies to all and any ice that might exist at some time in the future – right up to the (predicted) heat death of the universe – when all water will be ice, and the fact will only be of hypothetical interest as there will no localised concentrations of energy sufficient to actually melt any ice. This is an epistemological challenge: on what grounds can we make a statement about any ice, given that much of that ice has existed, exists or will exist, well away from the reach of human observers. How can we have knowledge of the behaviour of ice that we have no knowledge of. There is surely ice on planets and moons in solar systems in galaxies so far away or obscured by so much space dust that we do not even know the galaxy exists. Yet science tells us that any sufficiently pure samples of this ice will behave in certain ways. One idea about how science works was in terms of induction – concluding general statements from (sufficient) individual cases. This complemented deduction, where what we already know necessarily implies new conclusions we might not have previously recognised. Perhaps we want to know what kind of person Chris is. It may be that other things we know already entail some knowledge of Chris as a person. For example: 1.  Chris is a science teacher. 2.  All science teachers are wonderful.

If we were confident that statements 1 and 2 are both correct, we could deduce that 3.  Chris is wonderful.

However, there is a sense in which deduction never tells us anything new – even if we can use it to deduce things we had not realised were the case. In a sense we already ‘knew’ that Chris is wonderful if we knew that s/he is a science teacher and that all science teachers are wonderful, but we had just not previously made the deduction. In one sense we had new knowledge when we made the connection, but in another sense, that knowledge was already (logically, if not explicitly) represented in the system of conceptions we held. One historical example used to discuss induction concerns the statement that ‘all swans are white’. Observers in Europe had between them seen many swans, and all of the reported observations were of white swans. This raised the question of at what point one might be justified in making a claim that ‘all swans are white’. We might compare this with the parallel example of a school laboratory technician who had just opened a delivery of a score of 250 ml beakers. Imagine the technician removed the first beaker from the box, and found it was cracked. Then the next beaker was removed and also found to be damaged. The technician might be tempted to exclaim ‘all these beakers are broken!’ A pedantic science teacher might respond that it was known only that two of the beakers were broken, and it was pure conjecture that the others, not yet inspected, were also damaged.

A Twenty-First Century Notion of Scientific Knowledge If the technician proceeded to remove each beaker in turn, inspect it and announce that damage had been identified, then we might begin to expect that the prediction that all were broken was going to prove correct. However, even after nineteen of the beakers had been judged damaged, we still would not have definite knowledge about the twentieth beaker, which could still be in perfect condition. In this situation, it is clear how we could be sure of the truth of the statement that ‘all these beakers are broken!’ – by inspection of the final beaker in the shipment. However, let us leave the (hypothetical) beaker uninspected in the box for the moment and consider a standard question from probability. Suppose someone were to flip a normal coin, one with distinct obverse (head) and reverse (tails) sides, with a normal symmetrical disc shape and made of material of fixed density. The chance of a flip producing heads (coin landing obverse facing up – H) is one in two – 50 per cent or 0.5. Now what if someone had just flipped the coin a number of times and got heads each time. Perhaps they had flipped the coin 19 times, and the results had been H H H H H H H H H H H H H H H H H H H. Given that, what is the chance of the next flip giving a head? You may wish to consider your answer, and your reasons for it. Perhaps you might like to consider if you would believe the next flip was more likely to give H, or T (tails, reverse side facing up), or if it was perhaps equally likely to give either. When people are asked about sequences such as H H H H, they very commonly suggest that the next flip is most likely to be T. The argument is often along the lines that a run like H H H H H is unlikely (about 3 per cent) so a T is more likely, or simply that a T is due. A mathematician would reject this response and point out that once you have the run H H H H then another flip can give only two options – H H H H H or H H H H T – and these are equally likely, so the chance of a head on the next flip is still 50 per cent. These are independent events, so the results already obtained do not influence what happens next. Unlike when one is drawing one of only four aces from a deck of cards, the universe does not have a limited number of possible head or tail results that we are using up when flipping coins. So back to our beakers. Beakers, unlike the quanticles of which they are comprised (see Chapter 12), cannot overlap – so an event which forces them into each other can lead to damage. Let us say that research has shown that beakers sent out from the suppliers sometimes arrive damaged, and in fact 5 per cent of beakers are broken in transit. So does that influence our expectation about the final beaker? If the only information we had available was that 5 per cent figure, then we might predict that, most likely (as in 95 per cent of cases), the beaker would be intact. However, that assumes our knowledge of the fate of the other 19 beakers in the shipment has no relevance. We might suspect, however, that it does not make sense to treat the 19 broken beakers like 19 coin flips – as independent events. Rather we might consider that some single event has caused the beakers to break, and that our final beaker – being in the same shipment – was most likely subject to the same critical event. So the 5 per cent breakage rate is not as relevant to making a prediction as the knowledge that every other beaker in the box has been damaged. That is, we understand the situation of the uninspected

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MasterClass in Science Education beaker within a particular theoretical framework about how beakers get broken, rather than as a chance event with 5 per cent probability. However, strictly we still cannot know that ‘all these beakers are broken’ until we have actually checked all of those beakers. The situation with the swans is analogous. No matter how many swans we have spotted without coming across a non-white swan, we cannot be sure that ‘all swans are white’ until we have checked all of the swans – because perhaps there is a population somewhere that we have not yet investigated where not all of the swans are white. We might feel that there are reasonable grounds to assume all swans are white, but we should feel less justified in considering this as certain knowledge, as some kind of absolute law. The swans are different to our box of beakers example because it was possible to check every beaker and be sure all were broken. It is not feasible to check every swan, to be absolutely sure there is not an exception. Yet, logically, until we have checked every swan, we cannot be sure – so despite many thousands of European observers noticing many thousands of swans over many centuries without ever seeing a swan that was other than white, this did not provide logical proof of the general statement. Perhaps it does not matter that much if ‘all swans [really] are white’, but the logic here might suggest that we also have to give up on all those other general statements about melting points, half-lives, thermal conductivities, molecular masses, numbers of chromosomes and so forth that populate science data books, let alone statements that photosynthesis (always) requires light, that energy is (always) conserved, that a mole of gas under standard conditions (always) occupies a particular volume and so forth. That is, we must give up on science! Yet the logical difficulties with induction should be taken seriously. In fact, in the case of the swans, it did turn out that there were populations of black swans outside Europe that had not been inspected – so despite many thousands of European observers noticing many thousands of swans over many centuries without ever seeing a swan that was other than white, the inference that ‘all swans are white’ proved false.

The hypothetico-deductive method: Falsifications One response to the logical limitations of induction as a basis of general laws was to suggest that science proceeds instead by what became known as a ‘hypothetico-deductive method’ (Popper, 1934/1959). This suggests that science does not simply make arbitrary observations and draw conclusions, but rather uses observations to suggest hypotheses that are then tested experimentally. The notion that humans are equipped to infer the nature of the world by sufficient observations is replaced by the acceptance that the inferences we make are necessarily creative inventions of ways things may possibly be. The human imagination constructs an understanding that seems to fit with what we observe (as well as with our existing conceptions, see Chapter 6). That cannot be considered sufficient for scientific knowledge, so such constructions are considered to be conjectures to be tested.

A Twenty-First Century Notion of Scientific Knowledge Therefore, once a scientist develops a hypothesis, they then need to design a suitable test of the idea. Ideally, this test would be such that one outcome demonstrates without doubt that the hypothesis is correct, and any other outcome is clearly inconsistent with the hypothesis. This means there have to be clear predictions in advance about the observations that will follow from the test should the hypothesis be correct. This is a reasonable first approximation to the general approach used in science. However, it is widely accepted that science can never match this ideal in practice. There are two sets of problems. The first might seem familiar from the discussion above of the problem of induction. This is that whilst an outcome that matches the prediction developed from a hypothesis might seem encouraging, it does not prove a hypothesis is correct. Rather it shows the hypothesis is still in play: it offers support, but not confirmation. This is because the matching of prediction and outcome could be coincidental rather than due to a causal relationship. Even if many more predictions based on the hypotheses were made and found to be met, and we became strongly convinced we understood what was going on, we have not proved the hypothesis as a universal rule. The principle here is that data always underdetermines conclusions in the sense that any data set can always be found to also be consistent with some other hypothesis. (Perhaps the last beaker in the shipment is also cracked as predicted – but the damage could have occurred before shipment and gone unnoticed on packing.) In practice, we may have difficulty thinking up other hypotheses that match the data, and any others we do concoct may become quite convoluted and seem quite unfeasible, but we still cannot be absolutely sure. Consider some hypothetical student-collected data (see Tables 9.1 and 9.2). In the first case (Table 9.1), students heating water might spot a pattern that the temperature rose by 10°C for each minute of further heating. If they spotted the pattern after the third reading (85°C), then they might correctly predict the next reading (95°C). Human psychology being what it is (that is, one confirming instance may well be convincing when it fits our expectations), they might then be confident they know what further readings will be – 105°C, 115°C – but of course that does not happen. Similarly, students measuring the length of a spring subject to increasing load (Table 9.2) might well notice a pattern. Again, the students might predict correctly that the spring length Table 9.1  Measurements of the temperature of some water being heated Time/s

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MasterClass in Science Education would be 95 mm at a loading of 4 N, and then assume they could predict further lengths. However, once the elastic limit of the spring was exceeded, the results could be very different from the prediction. The natural attitude is to spot patterns, and then be easily convinced they can be generalised, on the basis of a very small number of confirming observations. Presumably ‘confirmation bias’ (see Chapter 7) arose because it was adaptive in the environments where early humans evolved over many thousands of years. The scientific attitude of caution, self-critique, looking for disconfirming examples, extensive replication, testing the range of application etc. is important in science, but would not have been the best way to thrive in prehistory. In the circumstances in which precivilised people lived, it is likely faint heart never (well, seldom) won fair maiden and fortune (somewhat) favoured the brave. People, all of us, including our students, are in a sense ‘programmed’ to be (a) hasty in drawing conclusions and (b) slow to change our minds, as that was adaptive to the environments in which our ancestors lived. Learning to think like scientists is to some extent about overcoming these tendencies (Wolpert, 1992). The hypothetico-deductive method responds to this bias by giving limited credit for passing tests, and instead valuing failed predictions which can falsify hypotheses. This is why it is sometimes called the ‘method of conjectures and refutations’ (Popper, 1989). If our predictions are right, we may have just hit lucky (the outcome was as expected, but perhaps not for the reason we assumed). But if our predictions are wrong, then clearly our thinking is on the wrong lines – so we have made some progress by eliminating one option. So, according to the hypothetico-deductive method, scientists should make bold conjectures (such as those that are derived from Einstein’s proposal of the invariance of the speed of light for all observers, see Chapter 3) – rather than safe predictions – and then proceed to try to falsify them, each time moving science forward by eliminating another false idea. There are at least two problems with this description of science (beyond the assumption scientists will be pleased when their ideas seem wrong). One is that, in principle, there may often be many possible alternatives – sometimes an infinite number – even if many seem unlikely. So the gradual elimination of individual alternatives from an infinite list seems a rather limited notion of scientific progress. The other problem is that, just as an outcome that matches a prediction does not prove we understand a system, so incorrect predictions may not actually logically demonstrate a refutation of the idea that led to the prediction. Our predictions can be wrong even if we have identified a correct principle or mechanism.

Theory of instrumentation We can see this if we consider our imaginary group of secondary students heating water. They predicted that the next reading after 95°C would be 105°C on the basis that each minute’s heating provided enough energy to increase temperature by 10°C; however, the next reading was not 105°C but rather 100°C. On a simplistic application of the falsification principle, this would suggest the idea being tested was wrong. However, our students may not

A Twenty-First Century Notion of Scientific Knowledge think this is the best way to explain their observations. After all, it seems intuitive that a particular amount of heat input should lead to the same amount of temperature change each time they make a measurement. So, accordingly, they may moot different conclusions: Perhaps the clock was read incorrectly and only a further 30 s had passed. zzPerhaps the clock was faulty and incorrectly indicated 60 s had passed when it had not. (It seems strange that the clock should suddenly go wrong, but then it might seem just as strange that the water should suddenly start behaving oddly); zzPerhaps the thermometer was not read correctly. zzPerhaps the thermometer stopped working – or perhaps it gives reliable readings only up to 100°C (again why suspect the water rather than the thermometer?) zz

Logically, these are all possibilities. Blaming the tools (or the technician) may seem a rather unprincipled response to a failed prediction, but real scientists certainly do make this move on occasion, and sometimes are later shown to be right in doing so. Another issue is that of measurement error due to limited precision of the instrument. Some readers may have scoffed at the neat data in our hypothetical examples. We might expect 11-year-olds new to laboratory work to produce more noisy data. Given that all empirical readings should be considered to include an error (±1°C?, ±2 mm?) it may be less clear if a data set fits a simple pattern or not, even when plotted as a graph. Scientific experiments usually involve not only a theoretical idea (heating for a set time increases temperature in a regular way) but also a theory of instrumentation (time can be measured accurately by hands on this dial moved by a wound spring of a certain kind, temperature can be measured by the length of a column of liquid inside a glass tube etc.) Much modern science also relies on complex analytical tools that translate raw data into a form that is interpretable. One of the most heralded scientific breakthroughs in recent times, the discovery of the Higgs boson, certainly illustrates this. The evidence for high-energy physics results depend upon highly convoluted interpretations of readings in complex instruments; calibrated and corrected by equally complex mathematical modelling and computer simulations. The results are many reinterpretations and treatments away from anything that could be considered raw data (Knorr Cetina, 1999). Whatever may have been observed, no one actually saw a boson. A scientific test is therefore a test of a prediction that combines a scientific idea plus a range of auxiliary assumptions about the materials (the purity of chemicals, the mice being of the expected strain, the semiconductor being doped at the right level etc. ) and the instrumentation used to collect and process the data (that includes the human instruments setting up the experiment carefully, the power supply not fluctuating, and maybe the laboratory temperature not dropping too much overnight). A falsification is a falsification of this compound, and so might be due to any one (or more) of its elements. So apparent refutations do not definitively rule out the ideas underpinning our predictions any more than confirmed predictions give us grounds to assume we fully understand a system. It is always more complex than that.

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MasterClass in Science Education Enquiry into practice: Reflecting the nature of science Record: (a)  some of your teaching when you are introducing a scientific principle, law, model or theory; (b)  conversations in student group work when students are undertaking practical work.

To what extent does the language used reflect a contemporary understanding of the nature of science rather than a notion of experiments simply confirming hypotheses and proving general conclusions leading to certain absolute knowledge? To what extent can you seek to modify classroom language towards a more authentic perspective of building up evidence to support arguments for provisionally accepting certain descriptions, accounts and positions that are open to revision in the light of new evidence or interpretations? Talk to students about their ideas of generalising from practical work they carry out. Do they assume that what they have found with this acid/metal/woodlouse/magnet/capacitor/waterweed/aldehyde etc. will apply to any other examples of the same class? zz zz

If so, why? If not, how do they bridge from the specific examples to general principles?

Scientific knowledge is theoretical It seems that the traditional approach to science (induction) is logically flawed, and that the twentieth-century hypothetico-deductive alternative that relies on falsification fails to provide definitive refutations. It is now appreciated that science relies on its theoretical perspectives as much as logic in drawing conclusions. Research questions are posed, and research data are understood as evidence, from within specific conceptual frameworks. Scientists ‘know’ that pure ice melted at the same temperature in the ice age as it does now, and will continue to do so until the end of the universe (even if that provides no melting opportunities) because ice is frozen water composed of molecules of a particular kind held in a particular lattice arrangement by certain types of bonds, so reflecting a certain level of internal energy that will need to be increased by a known amount for a phase transition to occur. The conclusion is a logical deduction based on accepted propositions about molecular structure, kinetic theory etc. It is sound, to the extent the theoretical apparatus it relies upon is sound. If we have got some of that theory wrong, we could be drawing the wrong conclusions. Just as if we were wrong about all science teachers being wonderful, then our deduction about Chris may prove incorrect. (Although, of course, Chris might still be wonderful even if the premises were flawed.) All scientific theory is, in principle, provisional, although we might suspect we are unlikely to have reason to revise our ideas about the structure of ice or the tenets of kinetic theory. In other cases, we may be relying upon current theory that

A Twenty-First Century Notion of Scientific Knowledge is less well established, or is known to need further development (e.g. about gravitational waves, string theory, negative energy).

A core issue for science education The detailed treatment of this issue here is justified because it links to one of the most substantive challenges in science education. We want students to have confidence in science as the source of reliable knowledge of the natural world, and yet we need to ensure that students understand that science does not have a method that can produce absolute, certain knowledge (see Figure 3.1). Technically, science produces provisional knowledge. If we think of knowledge as true, justified, belief (see Chapter 3), then ‘scientific knowledge’ is an oxymoron: science produces evidenced bases for thinking, but not a certain basis for belief. Indeed, as Chapter 10 reminds us, science should not be about belief.

Suggested further reading Allchin, D. (2013). Teaching the Nature of Science: Perspectives and Resources. St Paul, MN: SHiPS Educational Press. Taber, K. S. (2011). The natures of scientific thinking: Creativity as the handmaiden to logic in the development of public and personal knowledge. In M. S. Khine (Ed.), Advances in the Nature of Science Research: Concepts and Methodologies (pp. 51–74). Dordrecht: Springer.

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The Value of Not Believing in Science

Chapter outline What are we motivated to explain? (Of misbehaving electrons and missing socks) A scientific bias … Keeping religion out of science: Some complications How scientistic perspectives may be received by students You should not believe in evolution! Conclusion: In science you should not believe Suggested further reading

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This chapter explores the theme of the role of belief in science. This becomes most obviously relevant when theories (natural selection) or models (the Big Bang) that are taught in science are objected to by some students because of apparent conflict with their own worldviews and systems of belief. This raises the issue of how science teachers should respond (if at all) to the issue of the relationship between science and religion. A particular example highlighted in this chapter is that of denial, often on religious grounds, that macroevolution has occurred. This links to the theme of the Chapter 11: teaching about the theory of natural selection. However, the question of belief in science is relevant across all our science teaching.

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What are we motivated to explain? (Of misbehaving electrons and missing socks) Consider some things we could seek to explain: Potassium salts will give a lilac colour to a flame. The diversity of life on earth evolved from a common ancestral species. zzElectrolysis of water produces hydrogen and oxygen. zzFairies come into the house when we are not observing, and move or steal small objects. zzPlants respire only when it is too dark for them to photosynthesise. zzThe inert gases do not form chemical compounds. zzAphids are often pregnant at birth. zz zz

Scientists are expected to be curious and to seek to understand and be able to explain. Curiosity, or ‘epistemic hunger’, may even be considered to be a scientific value (or virtue). You might want to consider which things on the list you would be most hungry to explain – and perhaps consider the same question in relation to the students you teach. One point to make is that most of these topics concern things that most learners would have no experience of prior to school science. If one has never conducted, or at least seen, flame tests, then one has no reason to want to explain the colours produced. This is an important point when one is thinking about the purposes of laboratory or field work (see Chapter 14). Giving young people direct experience of phenomena is important, providing epistemic relevance, if we want to motivate them to seek explanations and understanding of those phenomena. Many school-age students will offer explanations for why noble gases do not react, and why plants respire only at night (Taber, 2014). People will try to explain non-existent phenomena! Students may well develop the idea that photosynthesis and respiration are alternative options in an organism’s energy economy, with green plants switching between them depending upon conditions, rather than seeing respiration as a universal and ongoing requirement for all living cells, and recognising photosynthesis and respiration as complementary parts of the metabolism of green plants. The example of the noble gases reminds us that we can all form alternative conceptions (see Chapter 6), not just our pupils. Many chemists worked under the assumption that ‘inert’ (noble) gases cannot form any compounds and so for a long time there were few attempts to prepare such compounds. Eventually, a few chemists attempted some reactions and found that a number of noble gas compounds could be formed. One story is that a lecturer set a tutorial problem for a university student to show by calculation that the formation of a hypothetical noble gas compound was not energetically possible. The student’s calculation actually showed the compound should be viable, and the lecturer, finding no error in the

The Value of Not Believing in Science calculation, was motivated to test the reaction in the laboratory. (When writing this chapter, I could not find a source for this account; however, I decided to include it, as I felt the narrative does useful pedagogic work – see Chapter 3.) I doubt many readers of this book would be motivated to understand why fairies are so mischievous. You probably share experiences of the underlying phenomenon that keys, socks, pens, eye glasses, cuff-links, rings and various other objects seem to either disappear for long periods or get moved to improbable places – even when no one else has been around to move them. Sometimes it seems a genuine mystery how that object could have got moved to there! Perhaps this is due to telekinesis. Perhaps there is a naughty teenage alien in orbit playing with a matter transporter. Perhaps it is just the quirkiness of the world at the quantum level: science tells us that there is a finite possibility that such events can happen due to quantummechanical tunnelling (finite, albeit infinitesimal). None of these seem serious contenders for an explanation. In the nineteenth century, most people in some communities, including many highly educated people, believed in fairies (Silver, 2008). Of course, few people saw them, and they were sometimes considered to be invisible. But then no one has seen a magnetic field or a gravitational field or radioactivity or the Higgs boson, and that does not stop people recruiting them into explanations. We have all seen some effects which have been explained in these terms (levitating trains, objects dropping, tracks in cloud chambers), just as most Victorians had experienced the effects of fairies. It is presumably in the nature of fairies to keep out of sight when we are looking, just as (according to the scientific evidence) it is in the nature of electrons to behave like waves only when we are not observing their positions. If electrons can behave differently according to whether we are observing them or not, and produce interference patterns only when we are not actually watching closely where they are going, then is it so strange that fairies are careful to steal only when they are sure there is no one around to see them? Skilled pickpockets are not observed stealing either, yet we do not dismiss pickpockets as an urban myth invented to explain the careless loss of wallets and purses. However, I doubt I have persuaded you it is worth investing your time and effort investigating the behaviour of fairies.

Enquiry into practice: Justifying what we consider credible Consider how you would justify (through argument and evidence, not authority) to a stubborn student why they should give more credence to the existence of the Higgs boson (or if you prefer, the neutron, or hyperconjugation or mitochondrial inheritance), for which they have no direct evidence, than to the existence of fairies, which could conveniently explain why their completed homework seems to have regularly gone missing before they can hand it in.

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A scientific bias … In Chapter 11, I refer to how a student undertaking a Web search relating to evolution will find information about the evidence for evolution, but also material which is said to be [sic] evidence against evolution. I have a bias here: I see the former as evidence, and the latter as material presented as evidence but which I am more cynical about. A sceptical reader may wonder why I accept the evidence for evolution and doubt that against it. You may assume this is because I have sufficient scientific expertise in geology, palaeontology, genetics, anatomy, environmental biology or some other relevant area – I do not. I am a scientist (a Chartered Scientist registered with the UK Science Council), but with a specialism as a teacher of chemistry and physics and as a science education researcher – I have never worked directly in any field dealing with the scientific evidence for evolution. If I reflect on the basis of my position, then I suspect I tend to accept the evidence for evolution and reject the ‘evidence’ presented against evolution because I have adopted a scientific worldview that accepts (nay, assumes) evolution happened, and so am more open to arguments and evidence that support my belief. That is, I am biased! I do not accept evolution because I have checked the validity and reliability of the evidence and demonstrated the lack of reliability and validity of what is presented as counter-evidence – rather, I accept the evidence that supports the conclusion I already hold. This does not seem a very scientific basis for evaluating evidence. I suspect I accept evolution because of enculturation. I was taught in school about evolution and read about it in books, and heard it discussed as a matter of fact in documentaries. The arguments seemed convincing on the basis of accounts of evidence constructed from data I have never analysed myself, and which I would largely not have the specialist knowledge to properly evaluate even now, and which I certainly could not have evaluated rigorously when I first learnt about evolution. In effect, I accept evolution because I accept the testimony of experts – I rely on the authority of science mostly mediated by science teachers, authors of popular science books and journalists writing for periodicals such as New Scientist and Scientific American. I actually expect the same is true for many science teachers – especially those like me who are not biologists. Moreover, most of those who have done relevant scientific work have examined in detail only some very small portion of the data available in one of the range of different fields which contribute to our knowledge here. I am not suggesting there is anything wrong with coming to accept evolution because, over many years, one absorbs the accounts sourced from science teachers, textbook authors, popular science books, scientific magazines and science documentaries on the broadcast media. However, this is a form of enculturation – accepting something because one is part of a community that shares that idea (e.g. be it macroevolution or fairies) and regularly reinforces it through various cultural activities (e.g. be that watching documentaries

The Value of Not Believing in Science about dinosaurs or habitually blaming the fairies when something goes missing). It is not in principle so different from why in some other societies people come to believe illness is due to evil spirits and witchcraft. I am not suggesting that the evidence for those latter beliefs is as sound and robust as the evidence for evolution. It is rather that in most societies, most people do not have the expertise to test and critique the evidence, so instead they just learn about it from their families and from authority figures such as elders. Whether that authority is a science teacher or the witch doctor may just be a matter of where they were born. Our worldviews are contingent on our upbringing and formative socialisation experiences. So much for the motto of the Royal Society: Nullius in verba – usually read as ‘take nobody’s  word for it’ (https://royalsociety.org/about-us/history/ – accessed 7 June 2017). Given the range of modern science, any scientist has to take a great deal on trust without checking it from first principles. Scientific knowledge claims are in part grounded in theories of instrumentation (see Chapter 9). Perhaps most scientists who use an electron microscope, or a mass spectrometer or a thermal cycler (PCR machine) do understand its general principles – but it is unlikely they understand the detailed specification and engineering of the model they actually use well enough to check from first principles that it will give valid, reliable and accurate results. They rely on (trust, take the word of) those with different expertise to have done their work well. Some research papers in high-energy physics have hundreds of authors. Each of those scientists and engineers contributed in some important way to the production of the scientific knowledge claims in the paper (Knorr Cetina, 1999) – but it is very unlikely any one of them could be considered to be a sufficient expert in all the theory, instrumentation and analytical techniques to be confident in the claims made without trusting that those in the team with complementary expertise have done their work well. This is not meant as a criticism. Modern society would not operate if no one could use a train, lift, phone, cashpoint machine, pedestrian crossing, microwave etc. unless they understood the device well enough to have built it themselves – specialisation is necessary for the modern world (Smith, 1827/1981). We rely on trust. I trust the people who designed, who constructed and who certified the safety of a lift I step into (even if it will always occur to me this is an act of faith). I also trust the scientific community when they tell me there is overwhelming evidence that life evolved on earth (or for that matter that there is a very strong case that human activity is changing the climate). This need not be a problem as long as we retain the scientific attitude of accepting that our conceptions of the world are necessarily based on limited evidence and imperfect understanding, and trust in the authority of experts, and so should remain open to review. We can ‘believe’ things in the sense of accepting and adopting them as the best available models, but we should not believe in the sense of having absolute faith. That kind of belief may be appropriate in religion but has no place in our scientific thinking or teaching.

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MasterClass in Science Education Enquiry into practice: Beliefs that may act as barriers to science learning Consider how a science department should respond to two hypothetical students: zz

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Julie is a 13-year-old who has become a vegan. She is interested in science, and wants to work with animals, but tells you she will not do any kind of animal dissection as she sees the killing of animals for human use as abhorrent. She will not opt to study biology if required to dissect. Charley is a 15-year-old from an indigenous American community who has a pantheistic faith. He objects to animals being kept in cages in the school laboratory as it is morally wrong to deny fellow creatures their freedom. After his concerns were politely noted, but ignored, he enters the laboratory at lunchtime and sets free the living specimens.

Is your science department aware of any moral commitments or faith positions that real students in the school hold that may create barriers for them in studying science? How might this be sensitively explored?

Keeping religion out of science: Some complications The science teacher charged with teaching about natural selection needs to be aware that some students will have faith-based reasons for rejecting evolution. This issue of scientific theory contradicting deeply held religious belief is considered in Chapter 11. However, the teacher also needs to be aware of other complications posed by groups that might be labelled as ‘ignorant Christians, ‘arrogant atheists’ and ‘pseudoscientists’.

Ignorant Christians Major world religions tend to have different branches and divisions. In Christianity, Islam and Judaism, there are influential thinkers who reject evolution, and many other influential thinkers who have no problems with evolution. It would be ignorant for a teacher to assume, for example, that any Muslim students in a class will automatically have problems with evolution, without a deeper understanding of the particular Islamic tradition they were brought up in. The majority religion in England, where the author taught and works, is Christianity. The established (i.e. official) church, the Anglican Church, has no problems with evolution. There are many Roman Catholics in England, and the Catholic Church also has no objection to the teaching of evolution. The same is true of Methodists. Traditionally, the Christian communities in England accept scientific accounts of the world, and indeed many early scientists in England were Christians who saw science as exploring the work of God, and so considered their scientific work as for the glory of God (see also Chapter 3). The book of nature (God’s work) was studied alongside scripture (seen as God’s Word). The biblical

The Value of Not Believing in Science accounts of the creation of the world (there are two somewhat different accounts in the first chapters of Genesis) were seen as offering poetic truth about the nature of man and his relationship with a creator God, rather than technical accounts of how God went about his creation. There are, however, some Christian communities in England who feel that the narratives in Genesis are meant as strict technical accounts. Readings of these accounts then usually require belief that God created the cosmos in six days; that the main groups of living things were each created separately as an act of special creation; that God created Adam directly from the dust, and then created Eve from a rib that Adam could manage without; and that before the fall (i.e. when Adam and Eve invited sin into the world by disobeying God and eating fruit from the tree of knowledge), animals such as lions, sharks, hyenas and vultures were all herbivores, and the biota all lived in peaceful coexistence. These communities also believe that the entire world was later flooded by God, who spared only four human couples and the animals they took on their ark as breeding stock to repopulate the world. It is not possible to marry these ideas with the fossil record, or indeed many other types of scientific evidence. Young earth creationists (YEC; as those who adopt these views are sometimes called) consider, on the basis of a literal reading of the Bible, that the earth was created within about the last 10,000 years, something completely at odds with well-evidenced ideas in geology and astronomy as well as biology. These beliefs largely developed in the United States in the early twentieth century in some Christian communities that now have churches in the UK. However, mainstream Christian thinking in England accepts the authority of science in understanding the nature of the world and considers apparent contradictions between science and scripture to be down to poor or overliteral interpretation of Scripture. It is sometimes said in such traditions that the Bible tells you how to go to heaven, not how the heavens go. If that seems like a rather modern slant on how Scripture should be understood, it is worth noting that this was an aphorism that was known to, and used by, Galileo Galilei, and which was consistent with the teaching of fourth-century Doctor of the (Christian) Church, Saint Augustine. Augustine considered it was foolish to adopt interpretations of Scripture that were clearly inconsistent with experience of the natural world. Yet research with secondary students (Taber et al., 2011) suggests that the science teachers in many English schools will find children in their classes who consider themselves Christians and are part of mainstream traditions that accept the authority of science in scientific matters, yet consider that their faith tradition requires them to believe that God created the world in six (they sometimes actually say seven) days and that all people on earth descend from Adam and Eve, who themselves were directly created. It seems that, in going to church and hearing Bible stories, many children assume that the accounts they hear of Adam and Eve, and the Great Flood, are accepted as technically correct accounts in their faith tradition. Of course, if children hear these stories regularly from when

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MasterClass in Science Education they are very young, then they are hardly likely to realise by themselves that these stories are presented as narratives offering metaphorical, poetic and moral messages. One child in this study told researchers confidently that the Pope certainly believed in the six-day creation, so teachers need to be aware that, even when children from Christian churches that reject evolution are in a small minority, many more children may wrongly assume that evolution is contrary to the teaching of their church.

Pseudoscientists Another problem concerns positions which may seem scientific to children, but which are at odds with the scientific approach. A key example is intelligent design (ID). ID claims to be a scientific perspective, and to have no formal affiliation with any religious position. Supporters have claimed it offers a scientific account competing with conventional accounts of natural selection and so should be taught as an alternative in schools. ID does not deny evolution, nor the fossil record, and does not deny the geological timescale accepted by science. However, it claims that the complexity of living organisms shows that the (what is sometimes characterised as) ‘blind chance’ element of natural selection is insufficient to explain living things. Where natural selection posits that variation, inheritance and differential fitness in particular environments have over an extremely long timescale given rise to all life on earth, the ID position is that natural selection by itself, without some external direction and guidance, is not sufficient. Various structures may be highlighted as examples in this argument. One is the flagellum used by bacteria to move around. These whip-like hairs are moved by a complex molecular structure. This would often be described as molecular machinery (sic, a metaphor that might imply something put together by a mechanic). The ‘motor’ of the flagellum has a number of parts which only work together because the particular proteins have the shapes they do and are arranged together as they are. Something which had only some of these components would just not work. (Imagine removing a few parts from a car engine, or a watch mechanism.) So natural selection would have to somehow provide each of these different components – each apparently useless by itself, and each representing a cost in terms of precious resource – and have them appear together and in the right arrangement before there was benefit to the bacterium. This is the kind of argument that was previously made against the evolution of larger structures such as eyes or wings. Evolutionary scientists explain how modern wings and eyes have developed from earlier structures that were not as useful, but still had some benefit. The biologist and writer Richard Dawkins (1988) has provided very convincing accounts of how this might work. A creature which lives in trees and which had somewhat looser flesh than others of its species might have some advantage in surviving jumps between trees, and in time a gliding organ may appear (initially by natural selection of the flabbiest arms), which may eventually become a wing. Variations among a population of creatures with insulating feathers may differentially assist gliding.

The Value of Not Believing in Science A small light-sensitive patch of skin offers some advantage over having no way of detecting when it is light. If that patch was in a pit in the skin, it might offer some useful indication of the direction light is coming from. Through many tiny variations, we could eventually get a modern mammalian eye – including the humor, cones and rods, the lens and the iris. Many of these accounts are just stories, imagined possibilities, until there is evidence of what did happen. But they give proof of feasibility. This is how science works, through an act of creative imagination that posits a possibility to tell us what kind of evidence it might be useful to look for, and which ideas to seek to test (Taber, 2011b). Arguments that some structures cannot be explained in this way can be equated with an assumption that no one has yet had the imagination to appreciate how the component parts might themselves have been of utility to the organism before being adopted into the evolving structure. That is, we have to avoid a logical fallacy here: just because we do not have an account yet, this provides no assurance we will not develop one in time. As is sometimes said: absence of evidence does not provide evidence of absence. (That is, the lack of evidence for some option is not of itself evidence against that option.) ID advocates adopt what is known as a ‘God of the gaps’ argument, which has largely been rejected by theologians. The God of the gaps stratagem is used to explain the steps in an account that science cannot yet explain. If God’s role is limited to explaining gaps in natural accounts, then if science ever has a complete narrative (given the Big Bang … first life on earth … the biota now), there will be no gaps left and so no need for God. The ID champions offer scientists challenges where they do not feel science has yet found evidenced accounts of how natural selection works, and they wager that no natural explanation can be found (or that by the time natural explanations are found, they will be able to offer other challenging examples). The mainstream scientific view is that just because we do not yet have all of the details, this does not mean that natural selection cannot provide the explanation. ID is not a scientific theory (Kitzmiller et al. v. Dover Area School District et al., 2005) because science provides naturalistic accounts and does not rely on supernatural elements. Of course, ID is consistent in principle with the idea that highly intelligent aliens came to earth and gave evolution here a push with some genetic engineering – which could be a naturalistic account. However, there is no viable evidence of that (although absence of evidence is not evidence of absence!), and this explanation potentially invites an infinite regress: were those aliens seeded by an even older alien civilisation, and if so, how did that species evolve?

Arrogant atheists Children in many science classes then are likely to be influenced by YEC who reject macroevolution, and they are quite likely to also come across ID supporters who accept evolution has occurred but suggest natural selection is an insufficient mechanism to explain how and why. Children are also quite likely to have come across popular books and television programmes presenting the ideas of a group of scientists who strongly argue that evolution has occurred,

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MasterClass in Science Education that it is a purely natural process, that it can in principle be fully explained by science, and so has no need of any consideration of God or gods. At first sight, such a view is perfectly consistent with school science and seems to be supporting the work of the science teacher. However, sadly this group of naturalists tend to then complicate matters by involving religion. The idea that science should seek and only discuss natural causes is referred to as ‘methodological naturalism’ (see Figure 10.1). This is the position recommended to the science teacher. A science teacher’s job is to teach the science. Some science teachers have strong personal religious faith, and others completely reject any religious ideas. Others take intermediate positions. However, this should be irrelevant to teaching natural selection (or other scientific ideas) as science is about natural accounts of the world, and these need to be based and evaluated purely on the scientific evidence. That is, a science teacher who believes that the world is God’s ongoing creation, and that God is in a sense the designer and first cause of the world, should be teaching the current scientific ideas about natural selection in just the same way as someone who completely rejects the idea of God. The scientific account must stand or fall on the scientific evidence available to support or challenge it, and it is not impacted upon by any complementary considerations of whether this account reflects God’s will. Methodological naturalism does not deny God any more than it acknowledges Him: it simply notes that such matters are outside the scope of science. Another flavour of naturalism, however, is metaphysical naturalism, which takes a very different stance. The methodological naturalist recognises some questions as being within the remit of science and insists these are treated scientifically. However, the metaphysical naturalist sees everything as within the scope of science, and so rejects the existence of anything supernatural. Metaphysical naturalists then adopt a form of scientism – that everything can in principle be addressed by science, and by science alone. Some versions of scientism go beyond the principle and suggest that science will eventually explain everything (or at least anything really worth explaining!). This perspective adopts atheism – the committed belief that there is no God. Atheism can be compared with deism (that the world was created by a God who set the creation going, but then no longer interfered), theism (that the world was created, and is sustained, by a God) and agnosticism (see Figure 10.1). Agnosticism is the view that the existence of God (or gods or other spiritual entities) must remain unsettled: that people cannot know for certain. This perspective was developed by Thomas Huxley (sometimes known as ‘Darwin’s bulldog’) in reaction to the tradition that most scientists had tended to believe in a creator God, where Huxley thought that scientists should limit their claims to knowledge to what they could clearly demonstrate on the basis of the available evidence. Huxley (1889) considered that, on the basis of the available evidence, he could not be convinced of either the existence or the non-existence of God, although he should always remain open to new evidence. Arguably, no new evidence has come to light since Huxley’s time to provide a scientific case for, or against, the existence of God. Many people would cite other kinds of evidence (personal experience, their intuition, tradition, Scripture etc.), but these are not scientific

The Value of Not Believing in Science

Figure 10.1  How the scientific approach of methodological naturalism relates to some key metaphysical positions.

matters, and so are not admissible in a scientific argument. Of course, to some who adopt scientism, anything that is not scientific evidence should never be given consideration (not just excluded from scientific dialogue); that is not the position recommended here, which is concerned with what counts in science. If, for example, a person has a deep personal relationship with God based on their subjective experiences, then that may be a very strong and totally logical basis for their faith, but this is not objective evidence that would be admissible to make a scientific (naturalistic) case that God exists. If YEC reject evolution, and ID supporters consider natural selection as insufficient to explain evolution, metaphysical materialists would argue that evolution does occur and can be explained by science, and that there is not only no need to invoke God, but there is no God to invoke. This position has been argued in popular media, and the most vocal champions of this view (sadly, including the great populariser of natural selection, Richard Dawkins) go further, by arguing that it is irrational to believe in God, or gods; that a belief in God is inconsistent with a scientific approach; and that religion, by offering accounts

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MasterClass in Science Education of the world that are alternative to science, competes with science. Religion is therefore said to be an enemy of rationality, and of science. Religion is considered simply primitive superstition.

Bad science The popular work of the metaphysical naturalists may be considered to be an example of what has been labelled ‘bad science’ – a term popularised by scientist and journalist Ben Goldacre (Best, 2015). Goldacre’s targets include pseudoscience (e.g. ID) as well as popular accounts of scientific work that cut corners, oversimplify, ignore provisos or sensationalise the science, or report work awaiting peer review. The general population, and the young people in school science classes, are likely to assume that headlines and stories in newspapers and on news broadcasts and in documentaries presenting the views of particular scientists, have the authority of ‘science’. There is no problem with the metaphysical naturalists being metaphysical naturalists, but when their work is presented in the popular media as if they speak for science, rather than for just a minority of individual scientists, it becomes bad science. This aggressive form of atheism, sometimes labelled as ‘new atheism’, sets out an opposition between science and religion, and offers a choice between rationality, science, evidence and progressive thought, on the one hand, and uncritical thinking, superstition, unquestioning faith and primitive thought, on the other. This view is, at best, unhelpful to science education. It seems to be based on the same kind of category error made by those who think evolution cannot have occurred because the scientific account does not match the Old Testament accounts of the creation, an attempt to compare what is incommensurable. Both YEC and the arrogant atheists seem to consider that a mode of thought should be applied where it would seem to be outside its range of application. The real issue here is how students might react to such views.

How scientistic perspectives may be received by students As a simple generalisation, let us consider different groups of students.

Atheist and non-religious students Students who themselves reject God, or who have been brought up without adherence to any particular faith, are likely to have little reason to feel threatened by the new atheists. Some of these students may still object to the views of new atheists on religion if they themselves have strong liberal views about multiculturalism and toleration of others, but they are unlikely to feel personally attacked.

The Value of Not Believing in Science

Students who reject scientific accounts on religious grounds Clearly, one should be careful in generalising across what is likely to be a diverse group from a range of faith backgrounds and living in different national societies. However, it is those students who reject scientific accounts on religious grounds that are being directly criticised by the new atheists – who imply they are not only wrong, but irrational and primitive in their thinking. Some students in this group will likely be antithetical to science in any case. However, research in the United States (in parts of which this group of students reflects the norm) shows that many students who reject some specific scientific accounts on religious grounds are otherwise very positive about science, and even open to working in science in areas that do not directly relate to the points of contention (Long, 2011). The scientistic atheist’s implied message to these students is that they are not suitable to become scientists as they adopt ideas which are contrary to science. This does not seem a very positive message, and it is hardly likely to encourage engagement in science classrooms.

Religious students who do accept scientific accounts of the world In a country such as England, the majority of students are religious to some degree (and most of these consider themselves Christian), but do not see any inherent conflict between this personal matter and the content of science. These students come to science classes with varied degrees of interest and motivation but have no problems with science on the grounds of their religious affiliation – as the mainstream Christian tradition is open to and supportive of science, and respects scientific findings. Even if these students do not fully appreciate the way Scriptural accounts of the creation of the world and its biota are understood in their own religious traditions, they are unlikely to see science as inherently in conflict with their religion. Yet if they see the documentaries or read the books and pamphlets originating from the new atheists, they will suddenly find that they have been living with a false sense of harmony. They will be informed that there is a kind of intellectual war between science and religion, where only one side is right, and people need to choose. By implication, scientists are atheists (some are of course, but many are not). Religion is the enemy of reason, they will be told, and a reasonable person who respects science and evidence needs to reject the mumbo jumbo of religion. A science teacher may recognise that the new atheist suggestion that science rejects the supernatural such as God is not a statement of how scientists generally think today, but rather reflects a political aim: metaphysical naturalists aspire for their position to become adopted as a tenet of science (Taber, 2013c). Most schoolchildren will not be in a position to realise that the well-known scientists making this argument are not speaking with the authority of science, but are arrogantly offering their own worldview as if it was a norm in science. The implication for these students – the largest group in many classrooms – would seem to be that they can choose science, but only if they reject their religion. It is an understatement to point out that this is unhelpful to science teaching.

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You should not believe in evolution! Given that teaching the theory of natural selection to students who have no principled reason to object to it is challenging enough (see Chapter 11), having the additional complication of teaching students who object to it on religious grounds (or who have been informed by the new atheists that it is in competition with their religious views) adds a major additional complication. The approach that is recommended here is unlikely to completely avoid some degree of conflict for some students, but it should help in most cases. It is not the teacher’s job to ask students to believe in a scientific theory such as natural selection. Indeed, if teachers are doing their job well in teaching the theory, the students will not believe in it. Science is not about belief, and the role of the science teacher is not to persuade students that a scientific account is true. The science teacher is charged with helping students understand (and so be able to apply) the scientific models and theories. It is part of science teaching to help students see why scientists have come to currently adopt a particular idea, but they do not have to be convinced about it themselves. Indeed, we would hope that scientists remain open-minded – open to new evidence that challenges current ideas, or to a new way of thinking that actually makes better sense of the available evidence. A scientist should be convinced that the ideas they apply offer the best currently available basis for understanding the existing evidence, but not that they represent an absolute and final account of nature. This relates to the view of science presented in Chapter 9. Science is a process that creates, develops and refines conceptual tools for understanding the world. These tools are human constructions, the results of acts of imagination. Scientists may seek to develop theories that reflect how the world actually is, but it will always be an open question how close our best theories are to being precise descriptions of the world. Phlogiston seemed a good way of making sense of chemistry at one time, until a different conceptualisation was thought up that (slowly) came to be accepted as making better sense of the evidence. Newtonian mechanics and gravitation still provide very useful models, although more recent conceptualisations (special and general relativity) are now considered to offer a better account of nature. It seems unlikely that the basic tenets of natural selection will come to be replaced, but it would be arrogant to assume that our current conceptualisations of evolution will never be improved, indeed just as arrogant as those new atheists who assume that their vision of how science does away with any role for God in people’s lives (a personal view that they are perfectly entitled to) should be adopted by all scientists.

Conclusion: In science you should not believe We have to adopt commitments to certain ways of understanding the world simply to operate in it, and in practical terms, we often need faith that experts know what they are doing. The

The Value of Not Believing in Science patient with end-stage kidney failure is probably advised to start dialysis on the renal consultant’s say-so, without delaying until they have a full understanding of the diagnostic value of measurements of glomerular filtration rate in blood samples, the nature of their kidney disease and its consequences for their evolving blood chemistry, and the means by which an artificial kidney will support homeostasis. Science and other expertise can prove wrong, but often in life, taking some course of action is indicated, and prevarication may be counterproductive. Doing something on the best advice we can get may often be more sensible than waiting for certainty. However, we should always be aware that all human knowledge, whether of individuals or the canonical knowledge of groups (including scientists), is fallible and may be subject to refinement and sometimes replacement. In practical matters, having faith may be a virtue. In science, however, retaining a level of doubt is important. Not believing is a scientific value.

Suggested further reading Coll, R. K., Lay, M. C., & Taylor, N. (2008). Scientists and scientific thinking: Understanding scientific thinking through an investigation of scientists views about superstitions and religious beliefs. Eurasia Journal of Mathematics, Science & Technology Education, 4(3), 197–214. Taber, K. S. (2017). Knowledge, beliefs and pedagogy: How the nature of science should inform the aims of science education (and not just when teaching evolution). Cultural Studies of Science Education, 12(1), 81–91.

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A Challenge in Teaching Biology: Natural Selection

Chapter outline The evolution of the scientific consensus on evolution The problem of conceptualisation The problem of belief Suggested further reading

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Evolution by natural selection is one of the key ideas in modern biology, but learning about this idea is problematic for many learners. Indeed, there are two quite distinct issues here. For most learners, natural selection is a challenging theory to master. For some learners, and in some particular teaching contexts these learners will be the majority of a class, evolution is considered to be a morally unacceptable idea. This chapter will look at both of these types of challenges to science teaching.

The evolution of the scientific consensus on evolution Modern science evolved in part from natural philosophy complemented with craft traditions. Philosophy is not experimental, but rather explores the nature of things by reflective methods. Philosophers analyse ideas, and the language they are expressed through, and consider arguments relating to logical necessity and the like. Some schools of philosophy actually considered empirical sources of knowledge as less reliable than rational thought alone. The

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MasterClass in Science Education advent of modern science was possible because there were crafts that employed practical skills – such as grinding lenses – that supported the development of laboratory instrumentation. So the use of lenses to correct defects of vision began centuries before modern theories of optics, based on practical knowledge of what proved to be useful. Arguably, neither philosophical pondering on the nature of things nor the atheoretical outcome of trial and error counts as science. Only once there is an interplay between these two traditions – theories developed from and informing empirical tests – do we have science (see Figure 2.2).

Natural history begat biology Arguably, biology took longer to develop as a modern theoretical science than physics and chemistry, where candidates for natural laws were more readily found. Charles Darwin was what we might call an amateur natural history collector – famously when young preferring to add to his collection of beetle specimens rather than study. Darwin never set out to be a professional biologist, and there was not really such a profession for him to enter. His father’s plans for him to become a doctor floundered on his not tolerating the gore involved in the unsophisticated operations he viewed as a medical student. The fallback plan of entering the Church was delayed by Darwin’s conscience, as he had reservations about declaring adherence to specific articles of faith (required to enter holy orders) he found unconvincing. At that point, Darwin was certainly a theist and indeed Christian, but he was not comfortable with some of the specific points of Anglican creed. Although Darwin probably never totally gave up a belief in a creator God, his discoveries and experience of personal tragedy certainly led him to doubt this was the loving, caring, personal God of the Christian Gospels – but that was much later in his life. Darwin’s voyage on the Beagle resulted from the peculiarities of the English class system rather than being a sought career opportunity. British ships often carried ‘naturalists’ (much scientific work was undertaken on Cook’s voyages for example), and the Beagle’s surgeon, Robert McCormick, would have been expected to act as a naturalist and undertake observations and collect specimens. However, the captain did not want to dine alone for the duration of a long sea voyage, so sought a suitable addition to the ship’s company who had the standing of a gentleman. Protocol did not allow the captain to eat at a table with his officers or crew because of their different social origins. Darwin came from a suitable family and was recommended by one of his tutors. On such contingencies does history turn! Alfred Russel Wallace did not have Darwin’s social advantages, and he was a professional collector – he made his living from selling natural history specimens rather than contributing to scientific scholarship. This was a job with no assured income and no pension. He spent extended periods in South America, and then in the Malay Archipelago. Although he is now remembered for his scientific achievements, he survived by selling what he collected and publishing popular accounts of his travels. Late in life, he was awarded a government pension in recognition of his scientific contributions, but only after an extensive lobbying campaign orchestrated by Darwin.

A Challenge in Teaching Biology: Natural Selection

Conceptualising natural selection These two enthusiastic collectors independently discovered the theory which laid the groundwork for modern biological science (Darwin & Wallace, 1858). From an educational point of view, it is worthwhile considering two points: Both Darwin and Wallace spent decades working closely with diverse specimens from different parts of the world, and both spent considerable time actually observing species in their natural ecological environments. zzEven though On the Origin of Species … (Darwin, 1859/1968) is undoubtedly a seminal book which contributed significantly to major shifts in scientific and popular thinking, Darwin was aware there was a big problem with his theory. zz

In relation to the second point, no amount of observation of specimens could explain why characteristics that were produced by variation were not largely lost again by blending through breeding. The rediscovery of Mendel’s laws that led to genetics, which were then put on a formal mathematical basis by statisticians, allowed a neo-Darwinian synthesis that became the central framework for understanding so much in biology. This was taken one stage further with the identification of DNA as the genetic material in humans and most other species, and the modelling of its structure as suggesting a ‘possible copying mechanism’ – something that Crick and Watson commented had not ‘escaped [their] notice’ (p.737), when they reported their work in Nature. If the term ‘genius’ is useful (see Chapter 15), then surely Darwin (and Wallace for that matter) deserves the label. However, Darwin spent decades refining his ideas, and did so with the support of many correspondents with expertise in particular areas – not only the like of anatomists but also non-scientists such as farmers and pigeon-breeders.

Reception of natural selection We are then asking students to learn a theoretical framework which took its instigators many years to appreciate, and which was only then refined slowly through the work of a community over a further century. It is not the kind of idea that we can expect students to fully understand, appreciate and internalise in a couple of lessons. It is also worth commenting on the reception of Darwin’s work when he published it. Darwin made only a very vague reference to the evolution of mankind in Origin, but rather reserved his treatment of this particular case for The Descent of Man (Darwin, 1871/2006). Despite this, Origin became seen as a very controversial book. It is certainly not the case (as sometimes suggested) that society in general was scandalised, or even that the English Church was collectively opposed to the book (the reception was much more nuanced). Many scientists, and others who read liberally, had been exposed to evolutionary ideas before. Many in the dominant Anglican Church in England read Scripture figuratively at that time (see also Chapter 10), so some aspects of the theory that are controversial

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MasterClass in Science Education in some parts of the world today (in particular, the necessary timescale for evolution to occur) were not necessarily problematic to the devout at the time. At a time when spiritualism was popular, some saw evolution as explaining the possible existence of human-like creatures that science would exclude today. Wallace is said to have believed people shared the world with ‘preterhuman discarnate beings’ – thus giving scientific respectability to a belief in fairies (Silver, 2008, p. 153). Yet there were a great many in society who saw natural selection as a direct challenge to aspects of a deeply held worldview – and in some communities this is still very much the case today. There are then two sets of problems in teaching natural selection to school-age learners: the problem of conceptualisation (making sense of the theory and seeing why it offers a conceptual framework that is persuasive) and the problem of belief (that some learners consider the theory to be contrary to deeply held personal faith).

The problem of conceptualisation For many students in science classes, there will no principled objection to learning about natural selection. However, there are barriers to students developing a strong understanding of the theory. Theories act as frameworks for providing explanations and predictions, and – unlike laws – may require the coordination of a range of principles. A scientific law is usually relatively straightforward and is a description of what seems to be a universal natural pattern. So, for example, the law of universal gravitation states that there will always be an attractive force between two masses that is proportional to the product of the masses and inversely proportional to the square of the separation. This can be represented in a simple mathematical formula. It is an abstract idea that younger learners may find challenging, but it is fairly self-contained. The law itself allows prediction, but it offers a limited basis for explanation – except in the sense of using the law itself as the explanation (i.e. you can calculate results if you put the figures in the equation). The theory of natural selection relies on a whole set of propositions that need to be coordinated to provide a coherent explanatory framework (Taber, 2009). The learner has to understand how there are different types of living things, or species. Observation and immersion in the culture provide some knowledge of natural kinds, but this does not map especially well onto species. For example, for most young people in many modern societies, ‘fern’ would be a single type of living thing, rather than a collective term for over 10,000 different species. Members of the same species tend to have many characteristics in common, but there will be some variation among them. Members of a species can potentially breed, and the offspring will be members of that same species, and they will generally resemble their parents to some degree. That is, typically, offspring resemble their parents more than random members of the species (who they tend to resemble more than members of other species).

A Challenge in Teaching Biology: Natural Selection This is explained in terms of genes, which are passed from parents to offspring – although in sexually reproducing species in novel combinations of the parental genes. Genes are expressed in various characteristics – but of course it is more complex than that, so there may be dominant and recessive traits. Genes are regulated by other genes (so a butterfly has exactly the same set of genes as the caterpillar it developed from), and in response to environmental cues (in some species, individuals may change sex under certain conditions). Sexual dimorphism in some barnacles is so extreme that when Darwin studied one species he initially discarded the males, thinking they were just tiny parasites on the females. Variation allows individual differences in fitness, but this tends to be a contextual and relative affair. Being tall might have advantages in some circumstances, but then moving to a new habitat might give the advantage to the shorter specimen. Moreover, contingency plays a big role. Being faster and stronger than another member of your species is generally helpful, but you, and not your slower and weaker co-specific, may happen to be where the landslide or forest fire or pack of prey animals happen to be whilst your apparently less fit colleague was lucky enough to be somewhere else. One has to take the long view – over a very long time indeed – and in a particular environment, a darker shade, or longer feathers or a woodier trunk may (or may not) be selected. Slowly the average characteristics of the population shift. The kind of timescales over which such changes typically occur are not easily appreciated by young learners. This is complex enough, but describes evolution only within existing species. The theory of natural selection suggests not only that changes occur to species, but that all the different living forms share a common ancestral species. This is sometimes called ‘macroevolution’ – new species appear. Darwin’s popular account, after all, sought to explain the origin of species themselves. So one has to consider how different populations of the same species may become divided into separate breeding groups, which, if in somewhat different environments, will be subject to somewhat different selection pressures. Interbreeding is prevented by geographical separation – a rift valley or a wide river – and eventually divergence under different selection pressures leads to distinct species that will no longer interbreed even when they overlap in space. The common names of the three extant species of elephant hint at this process of populations separating and occupying different habitats: the African bush elephant, the African forest elephant and the Asian elephant. This allows us to understand why (what in common parlance is) one kind of living thing, say elephants, evolves into distinct types. A much greater act of imagination is needed to appreciate how such processes led from a common ancestor to the mosses, ferns, grasses, trees, worms, molluscs and all the other types of living things. What common ancestor was able to evolve into a beetle, a bat and a boa constrictor? And also into a sea slug, a swallow and a salmon? And into a daisy, a dragonfly and a dog? Clearly, the examples can be multiplied. It is perhaps not so challenging to conceive of how fur may have got darker or longer, once there is fur, but it is harder to appreciate how an ancestor without fur gave rise to one with fur; how limbs developed from no limbs, gills from no gills, leaves from no leaves, or brains from no brains. Science may offer an account, but we can appreciate why, for many people, such changes would seem miraculous.

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MasterClass in Science Education Enquiry into practice: Teacher knowledge of natural selection Chapter 4 explored the nature of teacher subject knowledge. This project idea may appeal to biology specialists. The project could be carried out in a school with different (cooperative) teachers in the science department but would also work well in a group of science teachers in preparation on initial teacher education courses. Explore teacher subject knowledge in relation to natural selection by interviewing teachers around three questions: 1. What is your scientific background – what areas of science have you studied to a high level? (This question will allow you to see which colleagues consider themselves to be biologists or to have a strong background in biology.) 2. Could you tell me what you understand of the scientific account of evolution – how science explains the wide diversity of different living things on earth? 3. If you were teaching about evolution to a class of 15- to 16-year-olds, what core ideas do you feel it would be necessary to teach them to give them a sufficient understanding of the scientific account?

Before actually carrying out any interviews, you might want to reflect upon how you would expect a biology specialist to respond, and how you might expect a science teacher with a physical science specialism and limited biology expertise to respond.

Why is natural selection difficult to understand? The reader who has read earlier chapters of this book will probably be able to suggest some reasons why understanding natural selection is problematic. Students tend to come to school with existing conceptions of the natural world (see Chapter 6). It is a matter of common experience that living things seem to exist in a number of particular forms and these will commonly be seen as fixed types. Usually, on the scale of an individual lifetime, or even on the scale of human history, this is a reasonable approximation. The natural attitude reflects common experience, and the common experience is (for example) that blackbirds begat blackbirds begat blackbirds begat blackbirds and so on – apparently ad infinitum. To appreciate macroevolution, one has to take a perspective well outside human experience. This then is an abstract idea. Moreover, natural selection has to be understood as a complex of different ideas – so each of these ideas needs to be understood in its own terms, and then coordinated into an explanatory framework. Learning tends to be incremental, occurring in small learning quanta (see Chapter 5). Building up a conceptual framework involves mastering the component parts, and then fitting them together. The limitations of human working memory suggest that mastering something complex such as natural selection will require some chunking. This then suggests students need to master and become familiar with the component ideas, which only after some consolidation can be chunked together into a coherent whole that can be effectively ‘mentipulated’ by the learner. So effective teaching of natural selection needs to be

A Challenge in Teaching Biology: Natural Selection extended in time; attempts to put the whole picture together in a few lessons may seem to give some immediate success, but without regular reinforcement, this is unlikely to become established as permanent learning. This is also an area where the teacher has to ask students to defer gratification and give them the benefit of the doubt. The effort put into mastering natural selection gives access to one of the most powerful explanatory frameworks in science, but only at the end of the process, where the component ideas can be coordinated into a coherent narrative. Successful teaching often relies on a strong relationship between teacher and students that includes a level of trust. Students have to trust that it is worth the effort learning these somewhat odd ideas during the process whilst the new learning seems of little power. (Perhaps it is not so surprising that many students taught natural selection seem to actually learn inheritance of acquired characteristics, see Figure 6.2.) Given the central importance of natural selection to biology, one might think that it is sensible for teachers to take the time to build up the ideas carefully, offering students as much support as they need (see Chapter 7) – whether the packed syllabuses and unitised teaching schemes found in some countries allow this may be another matter. Evolution can be used as a key idea in so many areas of biology, so it should be taught carefully, and slowly, near the start of a course, and then used as an organising theme to support much of the teaching of the rest of the subject.

The problem of belief It is not difficult to see that, for most students, mastering natural selection (that is, understanding the ideas well enough to use the theory to develop coherent explanations based upon the theory) is challenging. This is likely to apply to most students in most classes in most schools. In addition to this, there is an additional major barrier to effective teaching and learning which will be found less universally. This will apply to most or all students in classes in some schools in some parts of the world, and a minority of students in most classes in many parts of the world. Some students strongly believe that evolution, or at least macroevolution (where completely new types of living things appear), did not, and does not, and indeed cannot, occur. In science, theories are developed to explain particular phenomena – they are motivated by the phenomena. Natural selection is intended to explain how new types of living things evolve over long periods of time from quite different types. Many students simply do not accept that this occurred. For someone who rejects a phenomenon, there is no motivation for explaining it – if you do not actually believe in fairies (see Chapter 10), you are unlikely to wish to put valuable time and energy into studying them. So, consider the student who does not believe in evolution. If the species that are around today have, more or less, always been here, then why should anyone put effort into learning a complex theory explaining how it is possible that all these different living things derived from a common ancestor, something like a bacterium or an amoeba.

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Why is evolution rejected by some students as a matter of principle? Our everyday experience of the world suggests living things exist as certain limited types, which are stable over time, and do not change into other types. There is of course a vast amount of evidence that species have changed over time – but this is not evidence that people generally come across unmediated. Most people, for example, have limited experience of the fossil record. We know what fossils are, and there are many specimens of fossils of extinct species that have been dated within limited margins of error and can now be interpreted in terms of both being put in the context of environmental conditions they experienced and being placed on a timeline with other species from which they descended, and (where they have descendants) those species that evolved from them. There are other sources of evidence such as the geographical ranges of living species, comparative anatomy and analysis of genetic similarity between different species. None of this is obvious from the observations of living things most people make in their day-to-day lives, so learning about this evidence requires mediation – presented by someone who knows about the data, understands why it counts as evidence for evolution and is able to explain it at a level accessible to learners. Of course, the World Wide Web contains more than enough information and interpretation for someone who wanted to learn about natural selection to start to appreciate just how much scientific evidence has been found that fits into the evolutionary account of life on earth – so, in principle, a student who was interested could learn a lot from the Web. However, someone who did decide to research evolution on the Web would soon also come across many websites which suggest there has been no evolution, or at least no macroevolution, and that Darwin’s ideas were not only ‘just a theory’, but one which has since been shown to be wrong. There is indeed much material on the Web, of various kinds, which is said to provide evidence that the evolutionary account of life on earth is mistaken (if not indeed some kind of conspiracy to mislead). There are apparently technical and evidenced arguments, for example, for why the radioactive dating of geological samples is in error and misleading. (This provides an example of how, in science, the conclusions of an enquiry depend not only upon the theory motivating the particular hypothesis being tested, but also on accepting the theory underpinning any instruments and analytical tools used. This was discussed in Chapter 9.)

Some of our students may have different biases to us Consider a child who is brought up in a community that collectively rejects evolution. These communities certainly exist. Whereas my texts at school referred to evolution and claimed there is strong scientific evidence for evolution, this child is given school books that do not mention anything about evolution. I attended Christian churches as a child but do not recall anything being mentioned about evolution. But this child may attend a church (or some

A Challenge in Teaching Biology: Natural Selection other place of worship or similar communal activity) where evolution does get mentioned regularly – but in a context of it being part of some evil conspiracy. Perhaps it is associated with mankind turning away from God; with inviting evil or the devil into one’s life; in turning one’s back on eternal salvation – and indeed on one’s family and community. The child may be told that evolution is a myth used to justify sin. It is not fanciful that children will be told this – evolution (or rather the spreading of the idea of evolution) has variously been blamed for communism, promiscuity, drug use, high teenage pregnancy rates, the Nazis, homosexuality, crime and probably just about anything else that is seen as undesirable by some people. What about the scientific evidence? From time to time, there are public lectures in this community, where scientists come to talk and explain that some other scientists have misinterpreted the data and so are presenting false evidence. (This is a little like a charismatic political leader telling a rally of adoring followers that his opponents are spreading fake news.) These visiting speakers present their own ‘correct’ interpretations and some of the vast evidence which shows that macroevolution never occurred. Evolution is just a theory, which has not been proved, and different scientists have different opinions – but these scientists who have come to talk to your church, or perhaps your school class, are presenting a view consistent with what your parents and grandparents think, with what the community leaders think and with what your pastor thinks. Evolution is a false idea. Perhaps the child asks their science teacher what they think about evolution. If so, the teacher, a respected member of that community, may confirm that evolution is just an idea and probably false, or perhaps may reply that it is not something the parents would want brought up in the classroom. If I admit that I take evolution on trust (see Chapter 10), why would I expect a child brought up in such circumstances to do anything but reject evolution on trust? The hypothetical situation I have been describing really occurs in some parts of the world. Indeed, it has been found in parts of the United States – one of the most pro-science and technologically advanced societies in the world. In places in the United States, parents can take their children to natural history museums that offer dioramas showing how man coexisted with the dinosaurs (before they died in the Great Flood reported in the Bible and other religious and ancient texts). In some such communities, evolution is technically on the curriculum, but teachers will often omit it because they think it is mistaken, or because parents would object and seek their dismissal if they taught it, or they will quickly present it as a quirky or mistaken idea, or just another suggestion, and move on. We might wonder whether people encultured in such a community will question what they are taught given that they must be aware that many people in other communities do think evolution has occurred and is well evidenced. But then I know there are plenty of people in parts of the world who think that it is well established that disease is due to evil spirits and witchcraft – that does not persuade me, as I choose to think they are mistaken. Many readers of this book may appreciate the challenge here to the teacher charged with teaching the scientific account of evolution, but nonetheless suspect that this is not something

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MasterClass in Science Education that will concern them directly. This is an issue in certain communities – in some Islamic countries and in some parts of the United States. In England, for example, evolution is prescribed in a national curriculum, and there are no parts of the country where the local community rejects evolution en masse. This may be so, but it is important not to be complacent. In 2014, there was a case where one faith school in London was found to have interfered with public examination papers to redact questions on evolution so the girls in the school would not be asked about it. It transpired this was being done with the knowledge of the national examination board. Apparently, both the school and the examination board considered that it was acceptable for students to be denied the opportunity to answer questions on evolution, and, in consequence, denied the chance to earn the marks available for answering those questions, rather than ask the children to answer questions on science the school found objectionable. When this became public, the official examination regulator made it clear that it would consider cases of schools changing official examination papers as malpractice, but media reports suggested this was not an isolated case. Such a situation would not be likely to develop in a state-maintained school (in England), even if it had a faith flavour, as it would be required to be open to all elements of the community. In a multicultural society, classes will often contain children from a variety of backgrounds – so although evolution is no big deal for many in a class (any more than redox or electromagnetism is likely to be objected to), there may be some children who have been brought up to believe that evolution did not happen and is an objectionable notion, and perhaps the idea is considered to be against their religious beliefs. Sometimes, outside school, these particular children may largely mix with extended family members or with those from the same faith community. As a minority, and being respectful of teachers, these children may say nothing when evolution is taught in class, but they may be thinking that this science lesson is about something they should not accept or discuss, and they may feel, at best, uncomfortable. As teachers, we may be completely unaware of these feelings. Alternatively, such students may feel they do have to object and put the view that evolution is false and objectionable. This is difficult for the science teacher who is equipped to present the scientific account, but probably not to engage in arguments that are based on religious Scripture or creed. Most science teachers would feel that religious discussion does not belong in the science classroom – but from the particular student’s perspective, it was the teacher who raised an issue that impinged upon their religious faith.

How should we respond to students who object to being taught about evolution? As a scientist, the science teacher will not wish to respond that natural selection is just a theory, and not proven (technically true, but just as true of the other scientific ideas we teach – see Chapter 9); or that it is one idea among many (as natural selection, neo-Darwinism, is effectively a consensus idea in science); or that this is not important as it is just one

A Challenge in Teaching Biology: Natural Selection topic (as it is so central to biology). However, as a teacher – someone who always has some pastoral responsibility towards students – the science teacher does not wish to dismiss, or reject, a student’s strongly committed position. The student who rejects evolution on the basis of deep convictions closely linked to family and community identity, and who perhaps considers such a commitment essential to a religious duty or even eternal salvation, is not simply going to change their mind – no matter how much they like or respect their biology teacher. So consider two possible ways of presenting the science of evolution (see Table 11.1). The dogmatic approach suggests that the teacher has absolute knowledge and implies that there is no scope for reviewing this position. The reflective approach is more self-critical and open to review. Some students who reject evolution in principle may still be uncomfortable in being taught through the reflective approach, but they would surely find the dogmatic approach much more offensive. Moreover, the reflective approach is consistent with the nature of science (see Chapter 9), whereas the dogmatic approach presents an absolute notion of scientific knowledge more suited to religious thinking. Most importantly, the reflective approach does not ask students to change what they believe. In the science classroom, we do not champion or question anyone’s religion. What we do ask in science is that students understand the scientific theory and they appreciate why this idea has become the current consensus understanding in science. If they can do that, they can answer examination questions in science. Perhaps a better understanding of the theory and the evidence may lead them to question a faith-based rejection of evolution, but that should not be the aim of teaching. (The aims of the science curriculum were considered in Chapter 2.) Perhaps a better understanding of the scientific account will allow them to engage with arguments against the science from a position of securer knowledge of what it Table 11.1  Two approaches to teaching evolution The dogmatic approach

The reflective approach

Evolution has occurred. There is unquestionable evidence

There is extensive evidence that best makes sense if living things have evolved over time

Darwin worked out that all life on earth evolved from

Darwin suggested that a great many observations of the natural

a common ancestor, through the process of natural

world could be explained if all life on earth evolved from a

selection. Other scientists have since proved that Darwin

common ancestor, through the process of natural selection. This

was correct

proposal has been supported by a great deal of scientific research in different fields

Scientists believe in evolution and natural selection

Scientists believe that the best scientific (natural) explanation currently available for the diversity of life on earth is natural selection

Students need to accept this account of nature as it has the authority of science

Students need to understand the theory of natural selection, and appreciate why scientists have come to adopt this conceptualisation

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MasterClass in Science Education is that is actually being criticised. If we are confident of the science, then that is not something we should be concerned about. What is important though is that science is taught in a way that does not directly seek to challenge anyone’s beliefs, and that the science itself is not compromised. Presenting natural selection as theoretical and the best current naturalistic account (rather than as a proven, absolutely true account) is true to the science, and to the nature of science. It is against the nature of science to ever teach it (or any other model or theory) as a dogma. Finally, it should be noted that students will be used to the reflective approach from other curriculum areas. In history, social sciences and citizenship classes, students are expected to learn about positions and their grounds, without being expected to adopt them themselves. So a student might be asked to learn about the idea of free-market economics, and why some theorists argued it was the most advantageous approach; or the ideas driving the French revolution and why those ideas convinced many revolutionaries; or how otherwise decent Europeans were able to condone improper treatment of indigenous populations in ‘their’ colonies; or how Hitler and the Nazis were persuasive enough to build democratic support in Germany in the 1930s. It is expected they can understand, and indeed critique, such positions without having to commit to them themselves. Indeed, this argument has its parallel in science teaching. The science teacher who has a good knowledge of her or his students’ alternative conceptions (see Chapter 6), and who can understand how they have come to accept those ideas, is in a better position to persuade students that the scientific conceptions have greater merit. Good scientists – as much as good economists or historians – have to be able to imagine alternative possibilities, and seriously entertain and explore positions other than their own. A good science education needs to support this by avoiding any sense that science is dogmatic. A student who cannot consider different possibilities, and so is not able to entertain and appreciate an alternative position to their own, will make a poor scientist, just as they would make a poor economist or historian.

Suggested further reading National Academy of Sciences Working Group on Teaching Evolution (1998). Teaching about Evolution and the Nature of Science. Washington, DC: National Academy Press. Reiss, M. J. (2008). Should science educators deal with the science/religion issue? Studies in Science Education, 44(2), 157–186. Winterbottom, M. (2017). Teaching and learning biology. In K. S. Taber & B. Akpan (Eds.), Science Education: An International Course Companion (pp. 343–353). Rotterdam: Sense Publishers.

A Challenge in Teaching Chemistry: Submicroscopic Particle Models

Chapter outline The substance of chemistry all around us Motivating learning Particle models The chemist’s triplet Suggested further reading

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This chapter considers the challenge of teaching chemistry in school, and in particular why students may struggle to appreciate the nature and application of the molecular level models so important in chemical explanations. Knowing about student learning difficulties here can inform more effective classroom teaching. The chapter begins with some orientating questions. It may be helpful for the teacher reading this chapter to first consider the orientating questions: 1. Can you list common substances that students will be familiar with from their everyday lives (i.e. not including school chemistry lessons)? 2. Would you consider air, orange juice, glass and/or wood to be solids, liquids or gases? 3. How can a chemist determine if a sample of orange juice is pure? 4. Is it safe to drink fruit juice to which acid has been added? 5. If a manufacturer added a small amount of food additive E300 to a sample of orange juice to help preserve it during storage and transportation, could it still be considered pure orange juice? 6. If the melting temperature of solid iron is 1538°C, what will be the freezing temperature of liquid iron?

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MasterClass in Science Education 7. Where is the edge of a hydrogen atom? 8. Why does a solid object, such as an iron nail, expand when heated? How would you answer them? How would you expect students in your classes (at different ages) to answer them?

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The substance of chemistry all around us There are a number of challenges which potentially make school chemistry difficult for many learners. One of these is that chemistry concerns subject matter which is generally outside everyday experience. This may seem an odd statement, because, in a sense, chemistry is going on everywhere around us, and indeed inside us. However, a child’s everyday experience mostly concerns materials which are not usually directly explored in school chemistry. Most (if not all) materials that the child experiences are more complex than those dealt with in introductory chemistry classes. Chemistry focuses on the nature and reactions of substances – elements and compounds – and most of the time restricts itself to fairly pure samples. To be fair, this provides subject matter which is sufficiently complex for most students: the periodic table of elements, the activity series, acid–base reactions and so on. Perhaps the most commonly experienced substance in everyday life is water. Tap water is not completely pure water, but for many purposes it is close enough. Table salt is usually not just NaCl, as small amounts of other substances are often added to avoid caking and so ensure smooth pouring. Yet, to a first approximation, table salt is common salt – the compound sodium chloride.

How pure is your morning fruit juice? Most food stuffs are much more complex. ‘Pure’ orange juice is far from pure to a chemist – it is a complex mixture of different substances. The precise composition will naturally vary depending upon factors such as plant variety, growing conditions and ripeness at the point of harvesting. If a sample was adulterated with a small amount of a toxic compound not found in natural juice, then a chemist could potentially detect this. If, however, some extra ascorbic acid was added, then it may not be obvious as there is a considerable range in the level of ascorbic acid found in natural juices: some orange juices naturally contain twice the level of ascorbic acid of others. Indeed, we might pose the hypothetical situation of a supplier of orange juice using a source that was naturally at the low end of the range in ascorbic acid, and who decided to add extra ascorbic acid sourced from a different variety of orange to give more typical levels of vitamin C in their product. We might ask whether they should be allowed to describe this as ‘pure orange juice’ as it is actually orange juice laced with an additive extracted from oranges. And what if they, instead, used chemically identical ascorbic acid sourced from lemons to

A Challenge in Teaching Chemistry: Submicroscopic Particle Models boost the vitamin C levels of their ‘pure’ orange juice? Or, perhaps more likely, chemically identical ascorbic acid from a microbiological (bacterial) source? It is worth noting that manufacturers do often actually add extra ascorbic acid (E300, vitamin C) to their fruit drinks, so this is not just a bizarre thought experiment.

Do mixtures show changes of state? Most metals we come across tend to be alloys – mixtures. Petrol is a mix of different hydrocarbons and may contain other additives (not so long ago including toxic compounds of lead). Many ‘plastics’ are technically mixtures of closely related compounds. Glasses are mixtures. Wood is … well, very complex. Indeed, wood is probably best considered to be a kind of composite material (albeit put together by plants of the photosynthesising green type rather than the industrial manufacturing type). Early teaching about chemistry in lower secondary school classes often emphasises the states of matter and the changes of state between them. The account given in school strictly refers to samples of pure substances where there are sharp phase changes. Most materials are mixtures, and this model does not readily apply. Consider glass. During glass manufacture, the mixture is heated to temperatures that can be well over 1,000°C so that the glass flows. According to the simple solid–liquid–gas model, this would imply glass is a liquid at that temperature, and that, as it cools, it would reach a freezing (i.e. melting) temperature, when it would change – at a constant temperature – into a solid, only cooling further after the phase change was completed. This does not happen. Melting temperature and freezing temperature are the same, of course, but many students struggle with this as they think of ‘freezing temperature’ in terms of human experience, and in particular, snow and ice – and the idea of a freezing temperature that is (subjectively) very hot seems incongruent. The teacher has to realise that the concepts of melting temperature and freezing temperature are distinct and likely linked to different sets of empirical examples in most learners’ minds. Understanding kinetic theory (as the teacher does) provides a basis for these two distinct concepts to become subsumed under a new theoretical concept (that we might denote the ‘melting/freezing temperature’). Awareness of where students often struggle can inform teaching. Even when students seem to ‘get’ the theoretical model (of the three states, the changes of state and how to label them) when it is first introduced, when they meet examples of melting temperature, boiling temperature and freezing temperature later in school science, their own everyday experience of these phenomena may be drawn upon in interpreting teaching. So, whenever topics such as the freezing point of iron (still very hot in human terms) or the boiling point of nitrogen (very cold in human terms) arise, it is important to reiterate, and so reinforce, the scientific model and how these terms need to be understood in terms of the phase changes of particular substances, not human experience of what seems hot or cold. Measurements of very old glass windows reveal they are thicker at the bottom than the top. They were not made that way, but even at room temperature, the glass continues to flow

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MasterClass in Science Education very slowly. It has not entirely become a solid. With a mixture such as glass, there is no sudden absolute transition between liquid and solid. A mixture does not have a single boiling temperature either: rather it will fractionally distil, with different fractions having different compositions. If air is cooled, it liquefies in different fractions (at different temperatures) because air is not ‘a’ gas, but actually a mixture of gases. So, if we are not careful, a great deal of what we are teaching in chemistry is not motivated by the students’ everyday experience of handling materials, as chemistry deals with the more abstract and limited category of pure substances; and when students can draw upon their experience of things boiling and melting, this may actually mislead their thinking about the temperatures at which these changes happen. We can certainly find links between the chemistry we teach and everyday phenomena and applications – as when relating the behaviour of laboratory acids to those in citrus fruits and gastric juices. But science develops theoretical ideas to explain phenomena, and very few pure substances offer familiar phenomena to most people.

Motivating learning Chemistry teaching therefore has a challenge to motivate the learning of ideas about oxidation, alkali metals and so forth. One strategy teachers can employ is to provide practical work to observe phenomena that can suggest the need for explanations. This can be considered as providing epistemic relevance (see Chapter 14). This reverses a common order of teaching to use practical activities to motivate thinking about what may be going on (before teaching the accepted theory), rather than to illustrate taught concepts. Students are unlikely to spontaneously recreate technical chemical concepts, but the process of applying their imagination to generate ideas that can then be tested at least offers an authentic experience of the creative nature of science. All scientific concepts were thought up by someone, and initially just had the status of imagined possibilities until research tested their usefulness.

Particle models This is of course true of the core chemical idea that the stuff we can see, even if it seems a single coherent whole, like one grain of NaCl or one drop of water, is actually made up of myriad tiny particles. These are particles so tiny that they cannot be seen with the naked eye, with a magnifying glass or even down an optical microscope, no matter how powerful the magnification. This idea was imagined by some of the Ancient Greeks, for example Democritus. However, at that point, it remained an imagined possibility to be debated purely in philosophical terms (cf. Figure 1.6). Even when Dalton offered an updated version of the idea, it remained hypothetical as there was then no possibility of any direct test of the idea. Dalton’s atomic theory, and developments from it, offered a good deal of explanatory value, but for a long time was seen by many chemists as just an instrumental theory rather than an account of the actual nature of material (Chang, 2012).

A Challenge in Teaching Chemistry: Submicroscopic Particle Models Instrumental theories and models are adopted because they have affordances even if they are not considered to reflect how nature actually is. An example would be when the heliocentric (sun-centred) model of the solar [sic] system was initially presented as being a useful basis of calculation, rather than meant to be a descriptive account of the actual state of affairs. (It is worth noting that our modern term ‘solar system’ makes sense within the framework of a heliocentric model but would have been incongruent with a geocentric model.) Famously, Copernicus’s On the Revolutions of the Heavenly Spheres was printed with an unauthorised and unsigned preface pointing out that models such as that presented in the book may be useful even if not considered to be true. Some scientists used this approach as a way to avoid charges of heresy, a sensible tactic at the time given that Giordano Bruno was burnt at the stake for the capital crime of proclaiming progressive views about the nature of the universe. The preface in effect suggested ‘this account will make it easier to predict where objects will be located in the night sky, even if it assumes the earth goes around the sun when actually (we all know, the Bible tells us) all celestial objects are moving around the earth’. One of the papers that made Albert Einstein’s scientific reputation was on an application of the molecular theory of liquids to explain Brownian motion (which is the basis of a demonstration still often used in school science to illustrate kinetic theory) that ‘according to the molecular-kinetic theory of heat, bodies of a microscopically visible size suspended in liquids must, as a result of thermal molecular motions, perform motions of such magnitude that they can be easily observed with a microscope’ (Einstein, 1905). Einstein’s work made an important contribution to the shift towards most scientists accepting molecules as real entities (Gardner, 1979). Even today, it is not possible to directly see atoms or most molecules down a microscope – the wavelength of light puts inherent limits on the size of what is detectable with an optical microscope. Devices that can, just about, detect individual atoms – some electron microscopes, and scanning tunnelling microscopes – are not available in school laboratories. Images from such instruments can of course be accessed and shown in class, but it is in the nature of a decontextualised, magnified image that it does not directly offer a feel for how small the imaged object actually is, or the magnitude of the technical achievement required to construct instruments able to produce such images. (NB, accepting the images as what they are claimed to be relies on accepting the theory behind the instrumentation – see Chapter 9.) It is important for science teachers to give a realistic idea of how small atoms, ions or simple molecules are. It is quite common for students of lower secondary age to think that the particles they are told about in chemistry are very small, but just about visible – like the specks of dust seen when air is illuminated by shafts of light, or the particles in materials such as flour or fine sugar. In part, this is perhaps not helped when we use a word (‘particle’) which is in everyday experience often used to describe sugar or sand grains. Students readily develop alternative conceptions about scientific topics, both prior to and during lessons on these topics (see Chapter 6). These alternative conceptions can have a variety of origins (Taber, 2014), including the way in which students understand the language teachers use.

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The realm of quanticles We should perhaps use a different term to refer to ions, molecules, atoms etc. to distinguish them from very small particles that are still composed of enormous numbers of molecules or ions. The term ‘quanticle’ has been suggested, so even a tiny particle such as a single grain of sand or speck of dust is comprised of a vast number of much tinier quanticles. A key teaching point is that quanticles are not just smaller versions of more familiar particles. A particle of salt or sand has a definite volume with a clearly defined surface. A wellfocused microscope shows a very clear boundary between the particle and its surroundings. This is typical of macroscopic objects – that there are clear discontinuities between them and their environments. You can see or feel where a test tube or beaker stops. A quanticle such as an ion is just not like that. A quanticle is a fuzzy ball of fields that has no edge or surface. A hydrogen atom usually comprises one proton and one electron. In one model of the atom, the electron orbits the nucleus (in this case, the single proton) at a particular distance. More sophisticated models suggest that the electron is not located on some kind of orbital trajectory, but can be found at various distances from the nucleus. The electron is smeared out, rather than localised at any one place, until we observe it. The probability of finding the electron at some particular position varies according to distance from the nucleus, and it is possible to reflect this in terms of smeared-out electron density that can be represented with a series of contour lines. But there is not a final contour line which acts as a cut-off outside of which the electron could never be found. The probability of finding the electron at some distance from the nucleus finally reaches zero only at infinity. So, in theory, an atom centred in Brisbane could have its electron in Auckland, Paris, on the moon, in the sun or even somewhere near Alpha Centauri. If we treat the hydrogen atom as a familiar object and ask where its edge is, where all its stuff is contained, the answer is unhelpful. Something as small as a hydrogen atom actually (if we think in such classical terms) extends to the very edge of the universe. Indeed, on this basis, there can never be an isolated atom, as all the atoms in the universe are actually overlapping. We could argue the whole universe is in that sense a single molecule. This might be a conundrum to pose to a ‘gifted’ student who could respond to the challenge (see Chapter 15), but would likely confuse most students. We get around this inconvenient way of thinking about atoms by deciding that even if an electron can be anywhere, the model suggests it will nearly always be very close to the nucleus (virtually always, if on a scale taking the distance from Brisbane to Auckland as a referent), and so we will treat anywhere where the electron is very unlikely to be found as outside the atom. Normally we consider a probability envelope that represents where the electron would be found, say 95 per cent of the time – and on that basis the atom is indeed, very small. So even if a hydrogen atom with its proton in Brisbane could – in theory, with very low probability – have its electron over two million metres away in Auckland, we normally consider that

A Challenge in Teaching Chemistry: Submicroscopic Particle Models atom to be about 5 × 10−11 m in radius. If we draw an atom as a sphere with a 95 per cent probability envelope (as is often done), then 5 per cent of the time we would find the electron outside the atom as we have drawn it. That is not often, but it happens. Imagine rolling a pair of dice to see how often you get two sixes. Not very often, but if you keep at it, it would eventually happen (and, although it is unlikely, it could happen on the first throw). You are more likely to find the electron outside the (usual representation of the extent of the) atom than to throw two sixes. Electrons sometimes seem more like waves than particles so, under certain conditions, they are found to diffract, for example, in just the way billiard balls and other familiar objects do not. The functioning of a scanning tunnelling microscope makes use of quantummechanical tunnelling, where quanticles can occasionally move across barriers which (in classical terms) seem to exclude them. Consider a science teacher looking to jump across a wide river – say the Thames near Tower Bridge in London. It is not humanly possible to jump so far. However, if teachers were quanticles, then even though the river is too wide to cross by jumping, if a great many teachers made the attempt, then a few would somehow land on the other side. In the familiar world the impossible cannot happen, but in the world of quanticles ‘the impossible’ happens, if with low probability. The reference to overlapping atoms above highlights another important difference between familiar particles and quanticles. If two beakers are pushed into each other, they cannot overlap – either there is a kind of impasse or something gives. Quanticles have wave properties and can overlap. Two beakers cannot occupy the same space, but two atomic orbitals can overlap to produce a superposition. This allows molecules to form. On colliding, two billiard balls will move apart. Two molecules that collide will start to overlap and they may repel each other, or they may form a new complex entity. Quanticles are then different in important ways to particles we experience on the everyday scale (see Figure 12.1).

Figure 12.1  Students commonly misconstrue key features of the particle model of matter as taught in school.

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Misleading students about thermal expansion This is worth emphasising as students often miss this point (Taber, 2001), and think that the ‘particles’ (quanticles) referred to in chemistry are just very small versions of particles they experience directly (see Figure 12.1) – leading to explanations that are circular (e.g. glass is transparent, therefore it contains transparent particles; glass is transparent because it contains transparent particles). Atoms may be thought of as like tiny billiard balls, which can lead to some absurdities. Consider the following ideas: a) In a solid, all of the particles are tightly packed together, so the solid cannot be compressed. b) When a solid is heated, the amount of space between its particles increases, and the solid expands. c) When a solid is cooled, the amount of space between its particles decreases, and the solid contracts.

These ideas are commonly taught in school science. Yet (b) and (c), which require space between particles, contradict (a) which requires particles to be in contact. When I worked in schools, point (a) used to be taught to 11- to 12-year-olds, and most of them were able to learn and hold on to this idea. When they were about thirteen to fourteen years old, they were taught (b) and (c), but I do not recall ever being asked how that was possible, given (a). Yet the logical problem seems very clear. One way that students avoid this problem is to offer an alternative explanation. When a solid (or liquid) is heated, it expands because the particles of which it is made themselves expand. Most science teachers come across this explanation and it is often labelled as a misconception or alternative conception (see Figure 12.1) and generally marked wrong in tests and examinations. Yet, rationally, •  if a sample of a solid expands on heating and •  a solid is comprised of closely packed particles that are touching each other and •  the number of particles is fixed, then it follows that •  the particles are larger after the sample has been heated.

This is simple logic: a deduction. Consider a tiny sample of substance formed into a cubic shape and 1.00 mm across each edge. Let us assume it comprises 1021 particles arranged in a simple cubic array. There will be 107 particles across the sample’s edge in any direction. If the particles are in contact (preventing compression), then the length of each particle across its edge is 1.00 × 10−3−7 m = 1.00 × 10−10 m (or 1.00 Å). If we consider the cube to not have any spaces between the particles, then the volume of each particle is 1.00 × 10−9–21 m3 = 1.00 × 10−30 m3. If the sample is heated so that the edges now measure 1.01 mm, the edge of each atom is now 1.01 × 10−10 m, and the volume of each atom is now 1.03 × 10−30 m3.

A Challenge in Teaching Chemistry: Submicroscopic Particle Models When the sample expands, the close-packed atoms of which it is comprised expand in the same proportion. For ease of calculation here, there being ‘no space’ between particles is taken literally by our considering them to be cubes. If instead ‘touching’ spheres are assumed, then the edge lengths become diameters increasing from 1.00 Å to 1.01 Å, and the volume still changes, but from 6.8 × 10−31 m3 to 7.0 × 10−31 m3. Yet, in a science examination, a student suggesting the particles expand when a substance is heated will usually be marked wrong. I would argue that this version of what is happening has more credit than a version that relies on there being gaps between the particles. There is a professional dilemma for a teacher here – to teach incoherent nonsense that examination boards may be looking for, or to seek to offer a consistent, logical account. The real problem here is that the sample does not contain particles, if by ‘particles’ we mean entities that have clear diameters and volumes. The argument that the particles expand is wrong in the sense that quanticles do not have clearly defined sizes. However, the argument that there are gaps between the particles which get bigger seems to be even less creditworthy. There are no gaps between the quanticles. Although any reference to quanticles having distinct diameters and volumes is dubious, we do in chemistry make use of measurements and calculations of metallic radii, covalent radii, covalent bond lengths and van der Waals radii. These are well defined, but they are more specific than ‘the’ radius of an atom or ion. Strictly, a precise measurement of, for example, a metallic radius should also depend upon the temperature of measurement, as it will increase as the metal expands on heating. This makes it very harsh to refuse credit to a student who argues that a piece of iron expands on heating because the particles get bigger. That is a rather limited explanation but it is certainly more correct than suggesting the iron particles move apart as if there are increasing spaces between them. We can understand thermal expansion in terms of a model which describes the asymmetrical shape of the potential energy well that the quanticles can oscillate in (that results from the overall electrical field within the solid lattice), such that the average nuclear separation changes according to internal energy shared among the quanticles (i.e. how high up the ‘well’ the quanticle is). Advanced secondary students (e.g. about seventeen years old) can be taught that model, but it is hard to see how students would be able to make sense of this model when they are first taught about thermal expansion – they would not have the prerequisite learning in place (see Chapter 5). In summary, because of the nature of the particles comprising matter at submicroscopic scales (what are labelled here as ‘quanticles’), explaining thermal expansion simply in terms of particles either expanding or moving further apart is inadequate (the space taken up by the quanticles increases, and the distance between their centres increases). We can imagine various responses to this problem: a)  Do not teach about thermal expansion. b)  Teach about thermal expansion, but do not offer any explanatory model.

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The first option would seem a shame as this is a phenomenon with important everyday applications, and which can be readily demonstrated in the school laboratory (motivating epistemic hunger for an explanation). The second option seems something of a cop out given that science is about the interplay of observation and theory. ‘Here is something interesting, and we will offer you an explanation of what is going on in three or four years if you choose the right course options’ might not be very satisfactory for students. The third option, however, seems to be: i)  intellectually dishonest and against the spirit of science; ii)  likely to confuse or confound students.

It is therefore regrettable that this third option seems to be the commonest approach in practice, and often in keeping with what students are expected to regurgitate in examinations. The message here seems to be: ‘science is not expected to make a lot of sense: you just have to learn it for the test’. Here then I am recommending the fourth, more challenging, option. It is more challenging because it integrates teaching some content (thermal expansion) with teaching something of the nature of science (and see also Chapter 13 for another example of this), because it requires students to engage in critical and analytical discussion of ideas, and because it does not lead to a simple right answer that can then be memorised for an examination. The suggestion is that students are shown (through demonstrations and simple practicals) how materials normally expand on heating and contract on cooling. Students can (subject to a proper risk assessment) make a simple model thermometer, for example, using a boiling tube with a bung and capillary tubing; and the teacher may demonstrate using standard apparatus such as the brass ring and ball (where the ball either does or does not pass through the ring, depending on their relative temperatures). Students may then be reminded of the particle model of solids, liquids and gases, and may be asked to discuss and present ideas about what happens at the level of particles when thermal expansion and contractions take place. Students should also be asked to consider how their ideas might be tested – and in particular what kinds of evidence might lead them to suspect their idea was wrong or needed more development. Good work could be judged in terms of orderly group dialogue and clear representations of their ideas in terms of diagrams with text. The teacher then has to judge how much of the scientific account should be presented. (Note this sequence of activities involves the shifts expected in dialogic teaching: see Chapter 8, e.g. Figure 8.2.) It may seem odd to leave the work hanging, with (hopefully a

A Challenge in Teaching Chemistry: Submicroscopic Particle Models range of) suggested explanations that have not been settled. However, the task should be posed to students as one of developing a model for testing – which is an important aspect of scientific work. In science itself, it may take years for the movement between a conjectured model and sufficient testing for the model to be widely adopted in the scientific community. Arguably, school science fails to give a good feel for scientific processes when it is always presented in terms of lesson-sized chunks with definitive outcomes. This work is likely to be challenging for most students, but gifted students in the class (see Chapter 15) could be exposed to the very important exception of water: they could be asked to consider why ice floats, and how this might require a modification of their model. If this approach is adopted, it does not matter if students’ ideas are technically invalid (after all, so is the version taught in most science classes) as long as they are clear they are offering a model which is conjectural and would need to be tested as part of normal scientific processes. This approach relates to the idea of science learning that seeks ‘epistemic relevance’: ideas about submicroscopic particles that students will never see become relevant because they can be used to make sense of real phenomena students have observed. Enquiry into practice: Teaching for epistemic relevance It is suggested here that thermal expansion is taught as a phenomenon that can motivate students to seek explanations and develop their own models and representations of what might be going on. It is also suggested that the desired outcome is not a ‘right’ answer. Consider how you would set criteria for assessing student learning in this work (given the suggested objectives of the activity). If you are able to teach this topic in this way, how might you evaluate the success of the teaching episode and identify any modifications that might be indicated for applying this with subsequent classes?

Particles may expand, but they do not melt or boil or evaporate The previous section looked at one specific class of phenomena (thermal expansion) that is explored in school science in terms of particle theory. This is probably best seen as a physics example, but particle theory is fundamental to most school chemistry teaching. Without particle theory, much of the chemistry that can be taught in secondary school is limited to largely descriptive treatments: a long catalogue of physical properties and chemical reactions, and various ways of classifying substances and their reactions. The logic of modern chemical theory is that a great deal of the vast catalogue of chemical data can be systemised through the application of a theory which posits submicroscopic particles, where the observed behaviour of substances can be explained through a limited range of principles and ideas about those particles. Sadly, students commonly misunderstand this affordance of the theory. Where the scientific model explains the types of properties and behaviours that can be directly observed in terms of the very different nature of the quanticles

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Yet glass particles are not transparent; gold particles are not shiny; ice particles are not cold; wax particles do not melt easily; and copper particles do not conduct. That is not to say that glass particles are opaque or gold particles are dull etc., but rather these sentences make the error of applying macroscopic concepts (shiny, cold etc.) to quanticles which need to be described in rather different terms. To put this alternative conception into context, we might note that when Democritus proposed ‘atoms’, he saw them as hard, solid atomos (‘indivisible’) – a bit like tiny indestructible billiard balls, and not at all like the fuzzy balls of electric fields described above. Moreover, when atoms were (again) proposed at the start of early modern chemistry, acids, which are said to have a ‘sharp’ taste, were considered to be comprised of sharp, spiky particles. That is, acids are sharp because they have sharp particles.

zz

We often find that students’ alternative conceptions reflect now discounted historical scientific models.

The chemist’s triplet Alex Johnstone (1982) suggested one of the reasons why learning chemistry is so difficult is because it involves dealing with the observable world of substances and their reactions, and the realm of molecular level accounts used to explain the phenomena and a specialised set of symbolic representations. Often the teacher was working with all three at once, and this might well overload students’ working memories (see Chapter 5) and lead to them getting confused or frustrated. The situation is even more complex than this when we consider the distinction between the actual phenomena observed (something glows, or changes colour or smells atrocious, or some silty stuff appears at the bottom of the beaker, etc.) and the theoretical descriptions of phenomena using the concepts of chemistry (reaction, oxidation, neutralisation, precipitation, combustion etc.).

A Challenge in Teaching Chemistry: Submicroscopic Particle Models What Johnstone was pointing out was actually the impressive conceptual apparatus that chemists have developed to make sense of the vastly complicated set of chemical phenomena. Chemists have brought order to this extensive range of sights, sounds and smells (and in less ‘health and safety’ aware times, tastes) by developing conceptual categories (this substance is an oxidising agent; the process is a redox reaction), underpinned by theoretical models and mechanisms at the molecular scale (this bond is disrupted here; this orbital overlaps with this orbital; this electron is delocalised through the lattice; etc.). By assigning symbols to elements, one can show how compounds relate to elements through chemical formulae, and how substances change during reactions using chemical equations. Various other particular symbols are adopted to represent equilibria, transition states, activated complexes, enthalpy changes, electrode potentials, standard conditions and so forth. The ‘chemists’ triplet’ is a powerful resource for understanding and communicating chemistry. An authentic chemistry education will induct students into this conceptual toolkit. Johnstone’s warning should not lead us to try to teach chemistry without the triplet. However, Johnstone pointed out the potential cognitive load students are exposed to. An expert will have internalised this framework for thinking and talking (and writing) about chemistry, and so will draw upon it without great effort. It has become a second nature – a kind of second language. Because this theoretical apparatus is integrated in conceptual structure through much past learning and experience, it will be ‘chunked’ (see Chapter 5) when accessed by working memory, leaving capacity to ‘mentipulate’ specific chemical ideas. Unfortunately, this very level of expertise and automation can make the complexity of the underlying thinking invisible to the expert ‒ such as the science teacher. To the novice, such as the secondary school pupil, there is a lot going on here – and often too much to take it all in at once. Students need to be gradually inducted into familiarity with, and then application of, the resources of the chemist’s triplet. The teacher should think about the complexity and pacing of their explanations given the current stage of progression of the particular students being taught. The teacher also has to try to make explicit what they are doing when they draw upon these conceptual tools, and make explicit when they are using them. Theoretical categories such as oxidation are abstract generalisations – and so one step removed from what students actually saw (a flame, a colour change etc.). Molecular scale descriptions are explanatory accounts based on theoretical models involving imagined entities such as ions, molecules and electrons – not a description of directly observable objects that are just like everyday objects but much smaller (for example, see Figure 12.2).

Bridging between the macroscopic (molar) and submicroscopic (molecular) levels There is also an additional important feature of the triplet when one is considering the key symbolic tools of chemical formulae and equations. Consider the example:

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Figure 12.2  Perceived phenomena may be conceptualised both in formal macroscopic scientific descriptions and in theoretical models at a submicroscopic scale (after Taber, 2013e).

1.  hydrogen reacts with nitrogen to form ammonia 2.  hydrogen + nitrogen ⇌ ammonia 3. 3H2 + N2 ⇌ 2NH3

(1) is a statement of a particular chemical reaction. In (2) that statement has been rewritten as a word equation. (3) represents the same information as a formulae equation. Now this last version has several special affordances. Firstly, it shows that the same elements are involved before and after the reaction. This creates a challenge as compounds are not just mixtures of elements, and often have quite different properties to the elements: yet there is a sense that the element survives into the compound. Ammonia does not contain any of the element hydrogen, but some essence of the element exists there. Secondly, it offers quantitative information about the reaction (three moles of hydrogen react with one mole of nitrogen to produce two moles of ammonia: four moles of reactants (in the correct ratio) will give two moles of product). We should note, however, that the use of the ⇌ symbol here implies that this reaction will not go to completion and there will be an equilibrium that depends upon the conditions. Perhaps most significantly, (3) is a usefully ambiguous statement. It is ambiguous because it could refer to two different things: bench chemistry or theoretical molecular models. (3) could be read to mean, as above, that three moles of hydrogen react with one mole of nitrogen to produce two moles of ammonia. However, (3) could just as well be meant to tell us that at the molecular level of submicroscopic particles (quanticles), three molecules of hydrogen will react with one molecule of nitrogen to give two molecules of ammonia.

A Challenge in Teaching Chemistry: Submicroscopic Particle Models

Figure 12.3  Chemists can use the symbolic level to bridge between a technical macroscopic description and a molecular-level explanation (after Taber, 2017).

This ambiguity is useful as in thinking and communicating about chemistry, we can use such representations as a bridge between the macroscopic description that tells us about the level of manipulating chemicals at the bench and the submicroscopic theoretical models we use to explain that chemistry (see Figure 12.3). We can represent what is happening in terms of macroscopic substances, and then (as the representation is usefully ambiguous) read the representation in terms of the molecular level model; or we can represent a molecule or molecular level interaction and read from it the corresponding substance or chemical process. This is a powerful tool, albeit one that may confuse students if we are not careful to explain the shifts we make. The teacher should not discard this powerful apparatus, but should: a)  make herself or himself aware of which ‘registers’ they are using: i. direct observational language of what can be observed; ii. theoretical descriptions using abstract chemical concepts; iii. explanation based on submicroscopic models; iv. specialised symbolic representations; b) seek to monitor and control the pace at which these ideas are presented and used, especially with younger students new to chemistry; c) be explicit about when you are using theoretical concepts, molecular models or symbolic representations, and especially when shifting between levels (such as talking about a reaction between substances; representing it as an equation; and then referring to molecules and ions because the equation is assumed to stand for both levels, and so allows you to shift to talking about the other level that is represented).

This approach will not only help to avoid overloading and ‘losing’ students, but can also help scaffold their induction into the same practices by helping them internalise the resources of the triplet as they learn to understand and explain chemistry with these tools.

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MasterClass in Science Education Enquiry into practice: Identifying chemical shifts in lessons Anyone teaching chemistry might enquire into how they use the triplet in the classroom. This might work even better as a collaborative project with two or more teachers observing each other and discussing what they observe. Record some of your chemistry teaching. Ideally, use video and audio recording. Map out your teaching: Have the following four column headings below. Identify references under any of the four headings in the order they occur down the page. Where there are arguments or explanations making clear links, use arrows to show these. Phenomena (e.g. blue solution, flame) Theoretical macroscopic (e.g. reaction, oxidation, combustion) Symbolic representation (e.g. formulae, equations, graphs) Molecular level modelling (e.g. molecules, ions, electrons, bonds) Looking at the schematic you have produced, consider the complexity of the subject matter you have been teaching, and the level of thinking required to follow it: zzIs

this suitably matched to the age, ability and prior learning of the class?

zzCould

you do more to support students in following the arguments and explanations you give?

This research idea could be developed in a number of ways: zz compare

the complexity of the schematic for different topics/classes; especially conceptually dense examples of your teaching, and ask students from those classes to view short video extracts (a technique called stimulated recall) and interview them about their understanding; zz make attempts to be more self-aware of the levels and shifts in your teaching, and be explicit with students about these, and see if there is evidence from your actual teaching of any change in practice over time. zz identify

Suggested further reading De Jong, O., & Taber, K. S. (2014). The many faces of high school chemistry. In N. Lederman & S. K. Abell (Eds.), Handbook of Research in Science Education (Vol. 2, pp. 457–480). New York: Routledge. Johnson, P. M. (2012). Introducing particle theory. In K. S. Taber (Ed.), Teaching Secondary Chemistry (2nd ed., pp. 49–73). London: Association for Science Education/John Murray. Taber, K. S. (2017). Teaching and learning chemistry. In K. S. Taber & B. Akpan (Eds.), Science Education: An International Course Companion (pp. 325–341). Rotterdam: Sense Publishers.

A Challenge in Teaching Physics: Electrical Circuits in the Lower Secondary School

Chapter outline Students’ conceptions of electricity An educational research project Suggested further reading

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Work with electrical circuits is often included in the lower secondary science curriculum, and many students entering secondary school will have some experience of building simple circuits in primary school. Despite this, it is found that those students who elect to study physics after they complete compulsory schooling often have serious difficulties in understanding what is going on in simple electrical circuits. This chapter will consider what makes the scientific understanding of electrical circuits so challenging for students and considers approaches to teaching simple ideas about circuits.

Students’ conceptions of electricity One of the simplest conceivable circuits is composed of three components – an electrochemical cell (such as the 1.5 V cells ubiquitous in powering many devices), a lamp and a piece of insulated wire (a lead). If the lamp is placed on the cell, so it makes contact with one terminal, the wire can be used to connect the other terminal of the cell to a different point on the lamp casing, so that the lamp is illuminated. This is possible because the lamp casing has two

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MasterClass in Science Education distinct areas of contact, insulated from each other, but connected to the two sides of the lamp filament. A complete circuit is made from one cell terminal, through a connecting path (lead, casing, filament, casing) back to the other cell terminal. Constructing such a simple circuit can prove to be a challenge for some students. Although youngsters will have plenty of everyday experience of electrical devices (although increasingly such devices have internal batteries charged without ever being seen), they will often have limited understanding of what is occurring. The science teacher may think in terms of a chemical reaction which provides a potential difference between the terminals of the cell that sets up a field through which momentum can be imparted to any suitably mobile charges; and of a metallic conductor which although apparently solid and unitary is actually a complex structure including a great many electrons that are in a conduction band of closely spaced energy levels and which can be readily moved through the metallic lattice. Little of this way of thinking is available to the typical 11-year-old on entering secondary science classes. The chemical processes in the cell will probably be studied only some years later in the upper secondary school. ‘Electricity’ is not understood in terms of something abstract like fields, but rather is likely a vague concept associated with overhead cables in fields, switches and household sockets, and various machines or devices. The child entering secondary school does not have access to the challenging models of matter at the submicroscopic level (see Chapter 12) needed to appreciate electrical conduction through metals. Leach and Scott (2002) proposed the notion of the ‘learning demand’ of particular content as being the difference between the scientific knowledge we set out as target learning in the curriculum and the starting points of the students who are being asked to do the learning. This is metaphorically the ‘distance’ from where they are now to where we want them to be. There is a strong case for suggesting that the learning demand in teaching circuit theory to lower secondary students is vast. A pessimist might argue that this is an inappropriate topic to teach students at this age, simply because conceptual analysis (i.e. considering the existing concepts required for learning a new concept, see Chapter 5) would indicate that a student cannot understand circuits properly without prerequisite knowledge that is simply not going to be available. That is, teaching children about circuit theory before they have learnt anything about atomic structure, electrons, metallic bonding, electric fields etc. seems ill-advised. In some ways, this is a very sound point of view. However, the influential psychologist Jerome Bruner once claimed that, with some careful thought, we could teach any topic to a child of any age in an intellectually honest way (Bruner, 1960). We might wonder whether this bold claim was meant to be taken at face value (how well might he teach quantum mechanics or epigenetics to a 5-year-old?), but it has been highly influential in encouraging teachers not to be defeatist about such challenges. There are also arguments for the value of teaching something about circuits at this age. One of these concerns relevance. Science teaching should be about things that students can relate to, not just about abstract notions which many students find difficult to engage with. Electrical devices are ubiquitous. Students will be familiar with household lights, washing machines, vacuum cleaners, hair driers, televisions and the like – even if for many students

A Challenge in Teaching Physics: Electrical Circuits in the Lower Secondary School that familiarity may not amount to a strong urge to understand how they work. Students these days also commonly have mobile devices such as phones and tablets – devices which need to be kept charged if they are to function. They also find that their earphones stop working reliably if they are not careful in looking after their leads. (Again, as Bluetooth earpieces become commoner, this experience will change.) Electrical circuits are relevant to everyone. Another consideration concerns the idea of a spiral curriculum, first championed by Bruner (1960). We know that even post-compulsory-education students have difficulties with basic circuit ideas, and this is unlikely to be helped by completely deferring the topic until late in their school career. A spiral curriculum is one that revisits the same topics at different points in the course of schooling, but each time asking students to engage with concepts at a deeper level. Learning at a particular age will be limited by the child’s intellectual development and relevant experience at that time, but nonetheless, some useful learning can be achieved which will provide useful foundations for subsequent learning later in schooling. In recent years, research in science education has increasingly explored the idea of learning progressions (Alonzo & Gotwals, 2012), how students may over time move through levels of understanding that bridge the learning demand of abstract and complex ideas. That is at least the theory – sadly, attempts at a spiral curriculum are sometimes experienced by students as simply ‘doing the same thing again’ and they may disengage if they think they are simply repeating something already covered and learnt. This may be a genuine criticism of a poorly constructed curriculum lacking sufficient progression, or may be a judgement based on surface similarity between present teaching and some vaguely recalled earlier experience. It may also somewhat reflect students’ limited appreciation of the nature of learning and teaching. Students may hold rather limited notions of how learning occurs and what teaching should involve! After all, they are not trained as teachers. Importantly, of course, every student is unique, and the curriculum may not fully reflect that. The careful reader will have noticed that a number of ideas, themes and examples introduced in this book are then revisited in other chapters. My intention is to use this pedagogic tactic to reinforce and develop key ideas. I hope that readers do not simply experience this as repeating the ‘same’ material – but of course every reader has their own unique resources for making sense of this book, and some will be more familiar with the ideas drawn upon, and some will have more classroom experience to relate the theoretical principles to. An author, like a teacher, makes assumptions about the existing knowledge, understanding and experience of potential readers, but unlike a classroom teacher (see Chapter 8) does not have the opportunity to directly interact with the audience and modify what is presented for different readers. The notion of the spiral curriculum seems sensible in terms of the ideas about student learning set out earlier in this book. However, although a spiral curriculum does allow the revisiting of ideas that support incremental, iterative processes of learning (see Chapter 5), it may not do so over an ideal timescale. It is important to reinforce labile new learning regularly and frequently to ensure consolidation, and a teacher can try to do this by returning to the key concepts in relevant contexts over the weeks and months after initial learning. This will provide effective consolidation of learning.

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MasterClass in Science Education The spiral curriculum may mean students spending two weeks working on a topic in their science lessons at age ten, and then another four weeks when they are twelve, and maybe a six-week spell in their physics classes at age fifteen. Unless there are many opportunities to revisit learning between these periods, the spiral nature of the curriculum may by itself offer a limited basis for reinforcing key learning. Enquiry into practice: Have you done this before? Do teacher and student perceptions of progression in the school curriculum match? If you are not teaching the topic of electricity or electric circuits in lower secondary science, you could apply this idea to many other science topics that are met as part of a spiral curriculum. Part A: Teacher perception. Consider setting out a table with three columns:

middle column: the content (in particular: ideas, concepts, principles) to be taught during a topic as part of the current year’s scheme of work; zzleft-hand column: the content of the same topic when it was previously experienced (e.g. in primary school); zzright-hand column: the content of the same topic when it is next met at a later stage in school. zz

Annotate the table with notes to show:

how the current teaching of the topic should build upon prior learning from the previous turn of the spiral curriculum; zzhow the current teaching of the topic could provide suitable foundations for subsequent learning at the next turn of the spiral curriculum. zz

To what extent can you identify progression in knowledge and understanding across these three phases of the school science experience? Part B: Pupil perception. Before teaching the topic, ask a sample of students to tell you what they remember about this topic from earlier teaching (if they remember ever meeting it before). After teaching the topic, ask the same sample of students to tell you whether anything seemed to be repeated from previous classes, what they felt was new and whether anything they learnt that was new was made easier by having studied the topic in earlier classes when they were younger. Reflection. Consider:

the extent to which pupil experiences matched your analysis of the intended progression in the curriculum; zzin particular, how much of what they should have learnt before seemed to be available to them during the current set of lessons; zzthe extent to which previous experience of the topic seemed to help the students in their current learning (at least, as far as their own observations suggest); zzwhether it might be productive for students of this age to have some notion of the nature and logic of a spiral curriculum. zz

A Challenge in Teaching Physics: Electrical Circuits in the Lower Secondary School

Purposes for teaching circuit theory in lower secondary school It may be wondered whether this is a topic that should be deferred until students are older and have learnt more of the prerequisite concepts that can be subsumed into developing a scientific conception of what goes on in an electric circuit. However, even if a teacher suspects that may be the best approach, they may find that the topic is mandated in the curriculum they are expected to teach. The extent to which teachers can make such choices will vary in different teaching contexts. The extent to which such decisions should be part of the professional prerogative of individual teachers is a moot point. A teacher should not waste precious resources (such as students’ time) trying to teach something they consider is inaccessible to their students. That said, governments and examination boards represent wider stakeholders who are entitled to have some influence on educational policy. Ideally, people with professional knowledge and experience should be trusted to make final decisions on such matters, but, in the real world, teachers may need to compromise on what they suspect is educationally best. There are a number of responses to this situation in the context of teaching about electrical circuits. One approach a teacher could take is to adopt the attitude that they are paid to teach what is prescribed, and so they should do so. That is, to ignore the fact that understanding the scientific model depends upon knowledge that is not available. This is a defeatist approach that expects and invites failure of effective learning, and also encourages student frustration. An intermediate approach might be to teach a hands-on module on building circuits which gives students useful practical experience without expecting or aiming to develop a strong theoretical model of circuits. This approach may encompass two separate considerations (each of which could be adopted on its own). The first draws upon some learning theories which consider that substantive learning is based on a cyclic process (Marek, 2009), where an early stage involves familiarisation with the material, and even what might be called a period of play, or at least playful exploration. This would suggest that a useful prerequisite to developing any theoretical understanding of circuits is some substantive experience of the domain. Time spent building different circuits brings familiarity with components, with circuit symbols and diagrams, and with the outcomes of different configurations. All of this provides a very useful basis for later learning. This is actually a very reasonable argument (and may indeed be the rationale for what students did if they were taught about circuits in primary school). The main problem with this approach is the same as potentially occurs with the spiral curriculum, discussed above. A period of playful exploration may be a very good basis for progressing understanding of a topic – as long as this experience is built upon shortly afterwards. It is questionable how effective such experience would be for 12-year-olds if they only studied the principles of circuits two or three years later in their schooling. Despite this, if the period of playful exploration was experienced positively, it could have useful affective consequences – students are likely to recall years later that they had enjoyed building circuits – even if not the details of

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MasterClass in Science Education what they built and how they bulit it, and what happened when they connected particular components together. The second consideration concerns the kind of circuits to be built. When the focus is on understanding the basic principles of circuits, it makes sense to focus on a limited number of components – cells, switches, lamps – and look at the effects of putting components in different series and parallel configurations. However, if those learning objectives are considered unrealistic, then a different approach may be indicated. This could include using light-dependent resistors, thermistors (highly temperature dependent resistors), logic gates, light-emitting diodes, motors and so forth. Students can build models of hall lights (that can be turned on or off from different locations), alarms of various kinds and other practical circuits. This may treat components largely as ‘black boxes’. This could be considered to be more electronics/technology than science, but all scientists sometimes have to work with systems that for them are black boxes (perhaps a particular statistical treatment; perhaps a nuclear magnetic resonance spectrometer that provides Fourier transforms; see also the comments in Chapter 10 about scientists needing to take things on trust) – especially when they work in multidisciplinary teams. This second approach offers a more respectable pedagogic response by teaching the prescribed topic but modifying the learning objectives so that students are not being asked to do something beyond their current capabilities. They get familiar with circuit work, perhaps enjoy making the circuits and learn about different kinds of sensors and transducers that can be used to do various kinds of useful tasks. This can be worthwhile learning. However, if the task assigned to the teacher by the curriculum is to help students learn circuit principles, then it will be a considerable compromise. This leads back to the question whether there is any merit in attempting to teach children of this age about circuit principles, given the obvious problems. Bruner’s bold claim about the potential of teachers raises the question of what can be considered to be an intellectually honest account. Such an account need not be the full sophisticated scientific account, for it may miss out many details and nuances, but must reflect the essence of the scientific idea. In designing a teaching narrative, the teacher needs to work towards an optimum level of simplification (Taber, 2000). Presentations that are not sufficiently simplified will lead to students misunderstanding, or being frustrated when failing to understand, the core ideas. Presentations that are oversimplified are those that fail to be intellectually honest by presenting a simplification which lacks the essence of the scientific idea, so giving students a false impression that they understand the science (and so potentially an impediment to later progression in understanding). This raises the question: What might count as an intellectually honest account of circuits that is accessible to lower secondary level students?

A Challenge in Teaching Physics: Electrical Circuits in the Lower Secondary School

An educational research project This question was tackled in a research project funded in the UK by the Economic and Social Research Council and the Institute of Physics, with support from the Gatsby Charitable Foundation and the Association for Science Education. The Effecting Principled Improvement in STEM Education (epiSTEMe) project set about designing modules for teaching based upon principles with strong research evidence. Exemplar modules were developed for 11- to 12-year-olds (‘Y7’ students) in four topics: two from mathematics and two from science – forces and electrical circuits. The modules were designed by a team from the University of Cambridge (UK) in collaboration with a group of teachers who expressed an interest in the project. Modules were trialled in partner schools before an attempt to evaluate the approach using an experimental design which compared a range of conceptual and affective outcomes (using instruments especially developed for the project) in classes using the materials versus a group of (as far as was practical) matched classes in schools not using the project materials (Ruthven et al., 2016).

Challenges of experimental research in education Randomised field trials (see Chapter 7) comparing innovations using control schools (an issue which requires considerable judgement – every school is unique, so which measures do you use to consider two schools similar enough?) are often considered the ideal way to evaluate teaching approaches, but they are not without their difficulty. Particular limitations with the epiSTEMe design were that (a) it proved difficult to enrol as many schools as had been anticipated; (b) there were (as tends to be the case in such work) complications of missing data and data collected outside the intended time window (e.g. if an immediate post-test is not done immediately after teaching, how much delay is acceptable before the data must be excluded from the analysis?); (c) differential dropout from the two conditions, potentially reducing the degree of match; (d) a bias towards the comparison condition as teachers there were carrying out their normal practice, whereas in the treatment condition, teachers were using a new scheme, teaching approach and materials, for the first time (see Chapter 8). Most teachers find it usually takes teaching the same material several times before they feel they optimise their approach – it takes experience to judge timings, find where the most emphasis should be put, judge when and how much support students will need for particular activities etc. A project which ran the innovation over, say, three years and took the measurements on the final year would make a more appropriate comparison, but would need more funding. Moreover, the rate of school staff turnover experienced during the epiSTEMe project suggests many (perhaps most) staff inducted into such a project would not be teaching the same topics to the same year group in the same school by the third year. Many schools prioritise staffing of more senior classes when timetabling, and it was found that teachers who agreed

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MasterClass in Science Education to be involved in using the project materials with their (expected) Y7 class might then at the start of the school year suddenly find they were not teaching that year group due to timetable adjustments. Another limitation with the epiSTEMe design was that, although resources allowed some monitoring of what was going on in the classes following the modules in a small sample of the lessons, there was no real notion of how the same topics were being taught in the classes being used as a comparison condition. (This ‘condition’ may well have encompassed considerable diversity of practice.) This might not have mattered had the study shown the teachers using the project materials were clearly getting more favourable outcomes than the teachers in the comparison schools. Even judging whether this was so raised issues about how to best analyse such a complex data set statistically: there is no one clear approach that is obviously indicated. In the event, most measured average differences between the two conditions were modest. Given this, it raises the question whether the approaches adopted in the ‘innovation’ classes were actually that different from what other teachers were doing anyway. Indeed, before proceeding to describe something of the approach taken in the electricity module, I think it is only fair to readers to point out that, in terms of learning about circuit ideas, the teachers who were using the project materials on average achieved slightly less than those considered to be a suitable comparison! This was the conclusion deduced from complex statistics (Ruthven et al., 2016), and is not obviously apparent from a visual inspection of the results (see Figure 13.1). In defence of the module (which the present author led the development of, so the reader may wish to be wary of possible bias), however, it could be considered that nearly reaching parity with current practice on the first attempt to teach with a new approach is quite an achievement. Chapter 4 suggested that ‘development of PCK [pedagogic content knowledge] requires cycles of teaching – that is, cycles of planning, classroom experience and evaluation of teaching that incorporates assessment of student learning’. Moreover, the teaching approach for this module combined physics teaching objectives with nature of science (NOS) teaching objectives (as explained below) and only the physics objectives were tested to be fair to those students in comparison classes where teachers were likely not emphasising NOS. One final point which is worth making, because it is salient for anyone thinking about doing experimental work in science education, is that, although the average achievement (measured as a gain from a test given at the start of the topic to a very similar test administered some time after finishing the topic) was comparable in the two conditions, this was not because all of the classes involved made similar levels of progress. Figure 13.1 shows the change in class average scores in both the project classes and the comparison classes. The large range in the average class gains in the control schools could possibly reflect very different teaching approaches. However, there is also a large range in the average gains in

A Challenge in Teaching Physics: Electrical Circuits in the Lower Secondary School

Figure 13.1  A visual representation of average measured knowledge gains in classes taking an innovative module compared with a matched sample of classes being taught the same topic (electricity) according to their schools’ usual schemes. (The arrows are from the average class score in a pretest to the average class score in a test given some weeks after completion of the topic: the size of the arrows therefore reflects the average change in score.)

the classes being taught the project module – where teachers were supposedly following the same scheme, teaching the same lessons with the same approach and using the same teaching materials. Indeed, in two classes, students on average apparently scored slightly less after being taught. That would suggest something very wrong with the module or the assessments – were it not that other teachers achieved clear positive gains teaching the ‘same’ module. The average difference between the two conditions that were the focus of this study was found to be small compared with the variations in learning in the different classes within either condition.

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The design of the module There were a number of features built into the design of the module informed by educational theory and research (see Figure 13.2). These are outlined here, but a more detailed account of the module is available elsewhere (Taber et al., 2015). Dialogic: The core of the module involved students working in groups to discuss and build circuit configurations, and explore helpful analogies. The P–O–E technique (make predictions, then observe what actually happens, then explain observations) was used to make student expectations explicit and highlight unexpected outcomes (White & Gunstone, 1992).

Figure 13.2  The overall design of the epiSTEMe module. (After figure 2 in Taber et al., 2016)

A Challenge in Teaching Physics: Electrical Circuits in the Lower Secondary School The discussion of several common teaching analogies for circuits gave scope for comparing alternative views. Periods of group work alternated with teacher-led whole-class work ensuring students had observed the expected outcomes (the authoritative voice of science) and collected and debated different views about how the analogies could provide models for what happens in circuits (cf. Figure 8.2). Nature of science: The module is an example of planning teaching to combine key objectives about science content (e.g. what happens to current in different parts of series and parallel circuits) with key objectives relating to learning about the nature of science (Taber et al., 2016). The way scientists use models and analogies was explicitly discussed, and the exploration of the value (strengths, limitations etc.) of three teaching models of electric circuits offered an illustration of how scientists develop and test models. Relevance: A general principle in the epiSTEMe project was that students should find work of relevance. Relevance can be understood in different ways (Stuckey et al., 2013), such as dealing with everyday applications of the science. In this module, the work was designed so that the natural phenomena themselves (as observed in terms of lamps lighting and meter readings) were used to motivate the learning – what might be termed ‘epistemic relevance’ (Taber, 2015a). This epistemic relevance reflects how, in science, observations lead to developing theory that motivates hypotheses for empirical testing. So students were not asked to demonstrate something they had been told should happen, but rather were asked to find out what happened, and how best to explain it, so informing predictions for other circuit configurations. Enquiry: In this way, the module was designed to give a flavour of genuine enquiry. A sequence of several lessons was spent on what superficially was the same activity: discussing what would happen if a particular circuit was built, building the circuit, seeing what happened and exploring explanations for the findings. However, as the complexity of the circuits increased, this provided a cycle of related activities offering a series of tests of student explanations. This is much more like real scientific enquiry, where there is ongoing engagement and development within a research project, than the experience of isolated practicals undertaken during one science lesson, and probably never met again. Chapter 14 develops this topic of enquiry in teaching science.

Suggested further reading De Winter, J. (2017). Teaching and learning physics. In K. S. Taber & B. Akpan (Eds.), Science Education: An International Course Companion (pp. 311–323). Rotterdam: Sense Publishers. Taber, K. S., de Trafford, T., & Quail, T. (2006). Conceptual resources for constructing the concepts of electricity: The role of models, analogies and imagination. Physics Education, 41, 155–160. The teaching materials for the module discussed in this chapter are available from http://people.ds.cam.ac.uk/kst24/KeithSTaber/epiSTEMe_electricity.html.

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Teaching Science as Enquiry and Supporting ‘Minds-on’ Practical Work

Chapter outline Enquiry in science and in school Why do we do practical work? Hands-on and minds-off? A rationale for practical work in science lessons Suggested further reading

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Enquiry is central to science. Scientific investigations and experiments are enquiry activities. An authentic science education should offer students some experience of undertaking enquiry. However, learning by enquiry is not seen as exclusively linked to learning science; there have long been calls for enquiry learning across the curriculum. Moreover, there is more than one notion of what might count as enquiry in the classroom. This chapter will offer some guidance on using enquiry in science lessons.

Enquiry in science and in school Science proceeds through enquiry – it is about finding things out. More specifically, it is about generating evidence-based claims to new knowledge that are strong enough to convince other scientists that they should become part of the public record of science (perhaps as useful ideas, perhaps even being accepted as the best current accounts of some aspect of nature).

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MasterClass in Science Education School students are seldom in a position to contribute to this process of generating new public knowledge, and this is an unrealistic aim for the school science curriculum. One traditional response is to make school science about learning as much as possible of the currently accepted best scientific accounts that have derived from the enquiries of actual professional scientists. The argument that has been developed in this book is that our decisions about the nature of the science lessons we want young learners to experience, and so the nature of the science teaching we plan, should be informed by the aims we have for science education. As we saw in Chapter 2, these aims may be multiple – such as to prepare youngsters for the world of work, prepare them for responsible citizenship, help them to develop their character and help to introduce them to aspects of the culture of the society in which they live. These aims need not be mutually exclusive but may suggest different emphases. If we want to help people to potentially become scientists, then they will need to know some science, but perhaps more importantly, they will need the mentality and skills base of scientists, in particular, enquiry skills. In science, this will include practical laboratory skills, but also encompasses cognitive skills relating to the processes involved, such as generating hypotheses, designing tests and analysing results to draw conclusions (see Table 14.1). Responsible citizens need to understand some science, and something of the nature of scientific enquiry, and to be able to apply critical skills to question claims and recognise poor arguments. The fully developed human is an enquirer, and someone who has developed a coherent value system that will guide that enquiry. That is, they have a notion of what is for them ‘the good life’ and experience their life as a kind of ongoing enquiry into how to achieve that way of living. This is perhaps linked to the notions of the pragmatist philosophers who saw human life as largely about solving practical problems (Biesta & Burbules, 2003). It also links to the idea of action research: adopting cycles of enquiry to respond to problems, issues and challenges in professional areas such as nursing, teaching and social work (Tripp, 2005). Table 14.1  Three of the categories used to survey student performance in science in England, Wales and Northern Ireland prior to the adoption of a national curriculum Category

Subcategory

Using observation

Using an identification key Observing similarities and differences Interpreting observations

Interpretation and application

Describing and using patterns in information Judging the applicability of a given generalisation Distinguishing degrees of inference Applying science conceptsGenerating alternative hypotheses

Design of investigations

Assessing testable statements Assessing experimental procedures Devising and describing observations

Adapted from Johnson (1989), Table 2.1.

Teaching Science as Enquiry and Supporting ‘Minds-on’ Practical Work Action research is often adopted by teachers and is usually understood to be a less formal strategy than other methodologies (such as ethnography and case study). It can sometimes be seen as not just a means to professional problem-solving, but an approach to improving one’s entire life (Whitehead, 1989). If enquiry seems to feature so heavily when one is considering the aims of science education, then it would seem to be central to good science teaching and learning. That does not imply every science lesson should be heavily enquiry based, but an authentic science education is certainly going to have a strong enquiry flavour.

Enquiry learning and discovery learning Unfortunately, like so many terms used in educational discourse, ‘enquiry’ can mean different things to different people. Enquiry is certainly not a kind of open-ended, unstructured learning by discovery (see Chapter 7). Play is very important in learning, especially with very young children, and exploring – and so becoming familiar with phenomena – can be an important stage in science learning. However, enquiry needs to be focused: students need to have some clear aims in mind to undertake enquiry activities, so that enquiry has a purpose. Usually, we would reserve ‘enquiry’ for activities that are quite substantive and somewhat open-ended. Students can be asked to find out the atomic number of potassium or the binomial name of humans or the common metal with the highest electrical conductivity. If they are meant to do this by accessing a reference source (and these days most likely a webpage nominated by a search engine), it probably does not deserve the title ‘enquiry’, even though the skills involved are certainly important. The level of enquiry involved in some learning activity may be considered in relation to two issues (see Figure 14.1): a)  how much choice the students have in what they are investigating (focus/purpose); b)  how much flexibility students have in how they carry out the enquiry (design/methods).

A senior scientist will identify a research question motivated by the current state of scientific knowledge, and will then design an enquiry in response to this question, before executing that plan (and being flexible in modifying it when appropriate). Student activity which reflects this would provide the highest level of enquiry-based learning – but clearly most school students are not in a position to take such responsibility, and so even if given such opportunities would likely attain limited useful learning from the process. At the opposite extreme is the ‘recipe’ practical, perhaps described as ‘an experiment to demonstrate X’. Whilst this is often labelled an experiment, the student is reduced to following precise instructions to produce standard results to demonstrate something that they are told will be the case at the outset. If the expected outcome is not found, then the likely assumption is that the instructions were not followed carefully enough. It is hardly surprising that practical work of that kind is often hands-on, but with ‘minds turned off ’.

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Figure 14.1  Degrees of demand in working towards authentic enquiry.

Why do we do practical work? Practical work is often seen as integral to school science, although the amount and type of practical work included in science classes varies across different national contexts and shifts over time. This leads to three central questions: 1.  Why do science practical work? 2.  How much practical work should be included in science lessons? 3.  What kinds of practicals are most valuable?

The costs of school practical work Science teachers usually think that it is important to include practical work in science classes. Most secondary pupils seem to enjoy the practical work, and indeed it is not uncommon for students entering the science classroom to ask ‘are we doing practical work today?’ or more specifically (but often inappropriately) ‘are we going to do an experiment today?’ In some national contexts, resource limitations mean science is taught in large classes (forty or more students) without any laboratory or technical support. However, in other countries, school science laboratories are a standard provision, and science teachers often feel that all science

Teaching Science as Enquiry and Supporting ‘Minds-on’ Practical Work lessons should be taught in laboratories so that practical work can be undertaken whenever it fits into the scheme of work. In these conditions, school science practicals use a lot of resources: specialised accommodation; specialised equipment; technical support; and a stock of consumables – chemicals, glassware, lamps and so on. Perhaps the major resource, however, is time. Practical work may occupy a substantial proportion of class time – of teaching time and student learning time. None of that is problematic, as long as this investment is an effective way of meeting our purposes in teaching science. There are, however, reasons to suspect that these resources are often not being used as well as they could be.

The benefits of practical work The two main areas where teachers expect practical work to be valuable in class relate to learning the science and being motivated to study science further. Yet research suggests that teachers are often being overoptimistic in both of these areas. Work undertaken in England, where traditionally a good deal of practical work has been included in lessons, suggests that science practical work is much less effective than many teachers might assume (Abrahams & Millar, 2008). It is true that most students in secondary science classes will report that they enjoy practical work, and often that is the thing they most look forward to about science lessons. Certainly, when students transfer from primary schools (often lacking specialised science teaching accommodation) to secondary schools, they often note how they were looking forward to, and most appreciate, being able to use real laboratory equipment (the Bunsen burner sometimes comes in for a special mention). However, for most pupils at least, that excitement will dim considerably over five years or so of science lessons. Research suggests that although students like the practical element of science classes, that by itself is seldom enough to persuade them to opt to do more science once it becomes elective. Some students enjoy science and find it fascinating. Strange as it may seem to science teachers, other students find it dull and boring. As a science enthusiast, it is good to keep reminding yourself that most students in most classes are not inherently interested in many of the science topics in the curriculum. Often what these students most appreciate about practical work is that it makes a change from listening to the teacher, and writing. They can move around the class and talk to their friends, and as long as they seem to be engaged in the right manipulations this will not get them in trouble. Time seems to pass much more quickly during a practical than when the teacher is presenting a topic or they are having to make notes. The exceptions may be practicals that require them to make repeated measurements or close observations over an extended period – these may be considered just as boring as having to do lots of writing. It is not the scientific work itself which many students value. However, this might not matter if science practical work was effective at supporting the learning of the science. Common sense might suggest this will be so. After all, many of the ideas met in school science are quite abstract, and practical work grounds those ideas and illustrates

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MasterClass in Science Education them. A number of ideas relating to learning met earlier in the book might be considered to support this expectation. For one thing, formal abstract ideas are likely to be learnt only by rote, unless the learner can make sense of them in terms of existing ideas. Practical experience supports the development of personal spontaneous concepts of the world, which provide the foundations for interpreting the formal abstract ideas taught through language (see Figure 12.2). Practical work can also introduce the phenomena that scientific theories and models are meant to explain, or can provide the practical illustrations of the concepts presented in class. People learn through a variety of modalities, and learning can be enhanced when it is multimodal; for example, handling as well as reading about, and seeing as well as listening (Jewitt et al., 2001). Despite all this, Abrahams (2011) found that when secondary students who had several years of experience of science lessons were asked about their recollections of practical work, most could remember only a small number of specific examples, and even then the details they did recall suggested they often had little recollection of what the purpose of the work was, and what, if any, concepts or principles it was expected to illustrate. Enquiry into practice: What do students make of practical work? Abraham’s findings seem a little counter-intuitive. It might seem that science practicals would be among the most memorable of school lesson activities. It is worth reflecting on which practicals you can clearly remember from your own days at school (or undergraduate study for that matter). Do you recall how the practical was meant to illustrate or motivate some theoretical concept, model or principle? It may be more useful to see if Abraham’s sample of students was atypical of the students you teach. You could set up an interview with a small sample of students (perhaps purposefully sampling some who are keen on science, and some who are not so keen; some who tend to do very well in science tests, and some who tend to perform poorly). If Abraham’s findings are generalisable to your teaching context, then these could easily be very short interviews. You may want to adopt the principle of ‘hierarchical focusing’ (Tomlinson, 1989) where you start by seeing what students can tell you spontaneously, and then introduce some increasing level of cuing. Phase 1: ‘Can you tell me about any practicals you have carried out in school science lessons since you entered the school?’ For each suggestion use follow-up questions, such as: zz‘What

can you tell me about that practical?’; ‘What did you do?’; What happened?’

Where the student responses do not cover this, ask: zz ‘What

do you think you were meant to find out/learn from that practical?’

Phase 2: For this phase, prepare some cards representing laboratory/fieldwork you know students have completed: the card would ideally include images of apparatus set-ups and information about materials used and actions carried out. However, the cards would not indicate purposes (‘an experiment to … ’; ‘a demonstration of … ’). Present each card in turn, and ask:

Teaching Science as Enquiry and Supporting ‘Minds-on’ Practical Work ‘Do you recall doing a practical like this?’ ‘Can you remember what happened in this practical?’ zz‘What do you think you were meant to find out/learn from that practical?’ zz zz

The purpose here is to get a feel for the extent of student recollections and understandings among a diverse sample of students: so it makes sense to customise your questioning for each interview to get as much useful information as possible. This kind of in-depth interviewing uses skills similar to those needed to refine teaching according to student responses (formative feedback) in real time in the classroom (see Chapter 8).

Hands-on and minds-off? It has been suggested that students often see science practical work as ‘minds-off ’. It may be that some see science lessons as a mixture of theory work and practicals, and feel that they can relax and ‘turn off ’ during the practicals as these provide light relief from the theory. If so, these same students probably play football, netball, basketball or other sports in physical exercise classes, where they presumably would not think they should be kicking, throwing and catching without any consideration of the wider context of the game. Of course, it is quite likely that there are students who see science lessons (as those in other subjects) as requiring them to do things – listen quietly when the teacher is talking, getting notes down completely, taking a thermometer reading every minute – rather than think things. Arguably, school often seems to put more immediate focus on not talking at the wrong time and completing written work than it does on actually thinking deeply about the content the lesson is meant to be about. Listening to the teacher, making notes, taking measurements and so forth, are all meant to be in service of developing scientific concepts, rather than being valuable outcomes in themselves. The norms of school life may become insidious. Consider an entire lesson spent on an engaging discussion where students genuinely elicit, exchange and challenge each other’s thinking, and so increase their understanding of some complex topic. It is quite likely many students would categorise that as not having done any ‘actual work’ in that lesson! They may even feel the teacher has not really done their job properly, or perhaps that by keeping the discussion going, they had scored some kind of victory over the teacher or the wider system by avoiding doing any real work. Teachers have a responsibility to help students appreciate that their real work in science lessons is largely cognitive, and so requires mental engagement with ideas and evidence and arguments, not just neat notes and rote learning of discrete statements. There is no value in being able to recite that a couple consists of two forces, equal in magnitude, opposite in direction and acting along different lines of action, unless one can actually understand what this means and apply the definition (see Figure 7.2).

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MasterClass in Science Education However, there may be another factor at play, which students and teachers can do less about. Humans have very limited capacity working memories (see Chapter 5). We can hold only a limited amount of novel information in mind at any one time. Despite this, we can (slowly) achieve expertise in areas of activity through extensive engagement. Over time, we represent a good deal of information (in the areas where we develop expertise) in long-term memory, in well-structured and highly integrated frameworks. This allows us to readily identify and access relevant information from memory, and because it has become chunked into pre-learnt structures, it then does not overload working memory. The science teacher overseeing a practical activity is very familiar with the particular practical; with the apparatus and techniques needed to complete the practical; and with the science underpinning the practical. Generally, the students are working with apparatus and techniques they are less familiar with to carry out a practical they have no prior knowledge of to support learning of some new area of science they are just being introduced to. The practical generally involves collecting and setting up apparatus and materials; carrying out some technique; observing and recording observations and measurements; and more often than not coordinating the work with a partner or other group members. The available working memory of a relative novice may be overloaded by the demands of carrying out tasks that would allow an expert (e.g. the teacher) capacity to be thinking about the underlying ideas. The teacher has to learn to think about the learning activity as it appears at the students’ ‘resolution’, not their own.

A rationale for practical work in science lessons Given these various research findings and complications of carrying out school practical work, it makes sense to take stock of why we might choose to do practical work (apart from placating students). Our reasons for including practical activities in the science classroom should reflect the aims for science education more generally (which were discussed in Chapter 2).

Science is a practical activity For most professional scientists, science is at least partially a practical activity carried out in the laboratory, field or observatory. However, science is never a practical activity per se, but rather is always practical activity motivated by suggesting, testing or developing theory. If we are setting practical work which is ‘minds-off ’, then in a very important sense, it is not the kind of practical activity undertaken in authentic science.

Students need to develop manipulative skills There are many skills students can learn in the school laboratory: safe use of a Bunsen burner, using a graduated burette, building circuits, reading a thermometer, using filter paper and a

Teaching Science as Enquiry and Supporting ‘Minds-on’ Practical Work filter funnel, using a metre bridge, dissecting a dead rat etc. We should teach those skills and techniques we are convinced that it is important for students to learn. Most of the specific skills and techniques students learn through school practical work are of no direct use in their everyday lives. Even students who will go into technical roles in science-related work are likely to use only a small number of the techniques they meet in school science – and indeed in industry and research much that used to be done by hand is automated or uses equipment rather different to school science fare. The typical science teacher may teach a small number of students during their careers who enter degree courses or jobs where they will be expected to use pipette fillers, but the vast majority will not, and for those who do, there will be when-needed training that will not take them very long to complete. (No responsible employer would rely on a new technician’s self-report that they think they remember doing that at school at some point.)

Students needs to develop enquiry skills What seems much more sensible is to focus on the value of learning enquiry skills – both because these are so central to what science is and because they support an invaluable way of thinking – an approach to the world based on collecting evidence and subjecting our ideas to critical examination. This is not only important to future scientists, and indeed to those taking up a wide range of types of employment, but is also valuable to any school leaver as a consumer, as a member of civil society or simply as a person who will meet and need to overcome challenges in reaching their goals in life. In science, such enquiry will likely have a practical component, and then some manipulative skills will be developed in relation to the particular instruments and techniques useful in carrying out those enquiries. As these skills will have been instrumental in meeting a more encompassing educational purpose (supporting the learning of the cognitive skills of enquiry and problem-solving), it is less important if they are of little specific relevance to the students’ future careers. The ability to imagine potential explanations and mechanisms, to design tests of one’s conjectures, to carefully observe, to systematically record observations, to interrogate potential evidence and so forth (see Table 14.1) are valuable life skills that can be learnt in science for the benefit of all learners.

Selecting practical work to offer epistemic relevance Few science teachers are likely to be able to completely reorganise their teaching around enquiry activities, although this book has argued that it is valuable to make sure learning science does have a strong enquiry aspect. Most likely, teachers will find that most of the time, they are using practical work outside the context of enquiry. Traditionally, much of this would be asking students to carry out activities to illustrate established theory. More often than not, the teacher teaches the principles first, so that the students know what they are expected to see. Given the challenges of rediscovering scientific principles from scratch (see Chapter 7), this seems quite sensible. However, there is a strong argument that if science learning is to

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MasterClass in Science Education reflect the nature of science itself, then it is important that students appreciate the dialectic at the heart of science between empirical observations and theoretical developments. Earlier chapters referred to epistemic relevance, and it was suggested (in Chapter 13) that practical work with circuits can offer phenomena that motivate the need for models and explanations. Epistemic relevance reflects how, in science, observations lead to developing theory that offers hypotheses for empirical testing (Taber, 2015a). So students were not asked to demonstrate something they had been told should happen, but rather to find out what happened, and how best to explain it, so developing models for informing predictions for other circuit configurations. There is a general principle here that so often we teach scientific models, theories, principles, laws and the like that historically were answers to the questions raised by scientists’ observations of the world without offering students anything of that context. The topic is taught as a given body of knowledge – a ‘rhetoric of conclusions’ (see Chapter 2). An alternative is to start by asking students to undertake practical activities which produce phenomena they have not yet been taught about at the theoretical level. If they observe the natural phenomena for themselves, especially ones that might appear counter-intuitive, then there is a motivation to develop an explanation, which involves the construction of some theory. Theory is taught not for its own sake, but in the context of natural phenomena. That is likely to engage more students, and to offer a more authentic experience of the rationale for developing scientific knowledge.

Suggested further reading Abrahams, I. (2017). Minds-on practical work for effective science learning. In K. S. Taber & B. Akpan (Eds.), Science Education: An International Course Companion (pp. 403–413). Rotterdam: Sense Publishers. Riga, F., Winterbottom, M., Harris, E., & Newby, L. (2017). Inquiry-based science education. In K. S. Taber & B. Akpan (Eds.), Science Education: An International Course Companion (pp. 247–261). Rotterdam: Sense Publishers.

Challenging the Gifted Young Scientist (and Other Young Scientists)

Chapter outline Why do the gifted deserve special consideration? Educative provision Approaches to working with the gifted Suggested further reading

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Why do the gifted deserve special consideration? In many national contexts, there is an identified group of learners variously referred to as ‘the gifted’, ‘the highly able’, ‘the talented’ or ‘the gifted and talented’, or given some similar designation. It is commonly argued that these learners have special needs because they are unlikely to fully benefit from educational provision designed for the typical learner. In some national contexts, there may be a requirement for schools and for teachers to demonstrate that they have taken the needs of this particular group into account when planning and teaching classes. It is argued here that it is important to take into account the needs of gifted learners in classes, but that this will be part of good practice when one is bearing in mind the needs of all students. It is also suggested that considering the students in a class who are most advanced in their learning may be a good starting point when planning teaching. This does not mean

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MasterClass in Science Education preferentially aiming the lesson at these students, but just that when you are differentiating your teaching (adjusting teaching for different groups of students), the most gifted learners provide a sensible starting point. This follows from considering differentiation alongside the general principle of scaffolding learning (see Chapter 7) to support students.

Who are the gifted? Although the idea of there being some gifted students with particular needs in the education system is widespread, precisely how such students are defined can vary a good deal from context to context. In some education systems, the focus is on exceptional children who clearly stand out from their peers – those who might attract labels such as ‘genius’. These students are not found in most classes, and teachers in typical schools come across only a few of these during their teaching careers. In other contexts, much more liberal definitions are used. In the English system, a localised norm-referenced system is used where it is expected that something like the top 10 per cent of all pupils in any particular school will be considered gifted and/or talented, so there will be a few such pupils in a typical class. The gifted might be identified by their having very high IQ scores, or by their performance in school subjects or through their having some recognisable but unusual ability. There is much variation in practice, so teachers in different contexts may be looking for overall intelligence, high levels of performance or indeed signs of potential – such as a student who is highly inquiring and asks many challenging questions, even when their test results are unimpressive (Taber, 2007b). Sometimes judgements are global – the gifted child is a gifted child. Sometimes giftedness is seen within more limited domains: in music, in mathematics or perhaps in science (or even more specifically, say, in physics). This level of diversity is not very helpful in guiding science teachers, beyond recommending that each teacher needs to be aware of any national or local policies and procedures that apply in their own teaching context. Schools, or even teaching departments, may have their own policies for working with gifted learners. It is important to keep in mind why teachers are asked to give particular consideration to these students. They may already have learnt the material being taught (some gifted students are precocious readers, some are effective autodidacts), sometimes to a level of depth and detail beyond the current curriculum. zzThey may find tasks which are challenging to most classmates relatively straightforward, and sometimes trivial and unengaging. zzThey may see solutions and consequences spontaneously and quickly when other students require careful leading through arguments in a stepwise manner. zzThey may complete work much more quickly than classmates. zzThey may gain little from peer discussions (i.e. within groups of students asked to share ideas, something generally encouraged as a dialogic technique – see Chapter 8). zz

Challenging the Gifted Young Scientist (and Other Young Scientists) They may readily see connections between ideas, topics and even different school subjects that do not occur to (and may overcomplicate things for) most students (Taber, 2018b).; zzBecause of all of the above points, they may want to ask about and explore what seem (to the teacher) to be side issues, such as work beyond the curriculum, fanciful thought experiments, alternative ways of understanding and the merits of discarded or ‘heretical’ scientific ideas. zz

As every learner is unique, and the term ‘gifted’ can be used so loosely, this does not mean that every student nominated as gifted will match this pattern, but at least some of these points are likely to apply at least some of the time to students labelled ‘gifted’. What is generally true is that schoolwork which regularly makes demands well within the ‘comfort zones’ of (any) students is likely both to bore them and fail to help them develop their understanding of science (see Figure 15.1) Enquiry into practice: Conceptualising giftedness Research suggests that students who consider intelligence as something pliable, which they can potentially develop, often have more productive attitudes to learning than those students who consider intelligence as fixed and totally outside their control. This raises the issue of how terms such as ‘gifted’ are understood and used in particular educational contexts. If your school uses a category such as ‘gifted’ to label some students, you might explore how different members of staff make sense of this label: Do they consider the category to have validity? How do they understand it? What in particular (if anything) do they expect of students the school has categorised as gifted? To what extent is there a common understanding among (a) the teaching staff and (b) the science department? If students are told who is considered gifted, then you might sensitively expand this enquiry to seek the views of some students who know they are considered gifted, and some who know they are not considered gifted. How do they understand these categories (is being gifted or not gifted an all-time judgement? Do they think these distinctions are valid or helpful?) And how do they think these labels influence their expectations, their actual work and the way they judge their success or otherwise in class?

Educative provision All students are entitled to teaching that is suitable to support their learning. Moreover, that learning has to be significant, so responding to the rationale for including science education in the compulsory school curriculum (see Chapter 2). An especially useful idea here is Vygotsky’s notion of the zone of next (or ‘proximal’) development that was mentioned in the context of assessment in Chapter 8. We can imagine that every student’s learning potential can be understood in terms of three zones: the zone of actual development (ZAD) the zone of proximal development (ZPD) zzthe zone of distal development (ZDD) zz zz

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Figure 15.1  Learners need to be challenged by work with higher-level demands.

These zones occupy a kind of phase space where the dimensions are those of intellectual development. The ZAD comprises current competency. The ZPD comprises development beyond current competency, but within reach when the student is offered some suitable scaffolding by the teacher or a more advanced peer. The ZDD represents competencies currently out of reach even with support (see Figure 15.2). If a student is set learning activities within the ZAD, then they have the capacity to complete work successfully, but with little potential to develop new capacities. If a student has already demonstrated skill in filtering solutions, drawing food chains, calculating lamp resistances in simple circuits or whatever, then asking them to do more of this type of work will not be challenging. It may keep students busy (and make classrooms look productive to a superficial observer), it may reinforce prior learning and increase efficiency at previously mastered tasks, and it may give students a sense of being successful: but the potential for substantive learning is limited. If, however, a student is set work in the ZDD, they will be unable to complete it, and so may find this frustrating as they will fail. If they are working in a group with more advanced students, then they will not be able to make substantive contributions to the group task, and even if the group is successful, the particular student will not learn a great deal – they would not be able to complete a similar task successfully alone in the future. If the teacher provides support to such an extent that the student can succeed, then the experience is unlikely to be engaging as the student will have a limited conceptualisation of what they have done (in effect following a recipe, as sometimes happens in school practical work – see Chapter 14), and again there will be limited learning.

Challenging the Gifted Young Scientist (and Other Young Scientists)

Figure 15.2  Significant learning is most likely when activities are pitched to be challenging for a learner, but temporary support is provided to facilitate success.

Similarly, if a student is set work in the ZPD without suitable support, they will fail, as tasks here are beyond their current competence. However, with suitable support, the learner can succeed. The difference between work set in the ZPD and work set in the ZDD is that in the former, the challenge is sufficiently close to current competencies to allow the student to meaningfully build upon them, with support, and make sufficient sense of activities to find them engaging – and so to learn from them. The extent of scaffolding offered (see Chapter 7) allows the student to internalise the new learning and gradually master the activities as support is faded, until they need no help to complete this type of task. At that point, these activities (which were previously within the ZPD) have become part of the ZAD. The ZAD has grown to encompass new learning, and the ZPD will also have grown as some things that would have been part of the ZDD have shifted into the ZPD as the new learning now provides a basis for accessing them (see Figure 15.2). Work in the ZDD offers little, if any, value to students, and therefore is likely to frustrate and demotivate them. There is a rationale for setting some classroom activities within the ZAD, as reinforcement and practice are sometimes important. In general though, work that is set in the ZAD is likely to readily become boring. A teacher should probably not ask students to work in their ZAD for whole lessons. The teacher’s task is then to balance challenge and support. Tasks in the ZAD offer no challenge. Tasks in the ZDD are too challenging, even with support. Tasks in the ZPD will be challenging, but can also be engaging and motivating when sufficient support is offered to allow the student to work towards success. Indeed, getting this balance right may well be a key to offering learning experiences that match the ‘flow’ experience (see Chapter 7) when students can become engrossed in the activities set. These

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MasterClass in Science Education principles apply to all learners – and differentiation relates to finding the balance between challenging and supporting students – as a task that is too challenging for some students in a class may offer no challenge at all for others.

Approaches to working with the gifted Various approaches have been suggested for working with gifted students. In some systems, these students are taken out of mainstream schooling into special institutions, or at least into a distinct classroom with its own curriculum. More often, forms of setting or streaming/banding are used to organise classes on the basis of judgements of ability, attainment, or potential. These approaches are inherently limited as there is always a spectrum of students, rather than a number of discrete groups of similar learners, and because every learner has a unique profile of strengths and weaknesses. Gifted students are not brilliant at everything, and some are ‘doubly exceptional’, meaning they may have particular strengths yet also special needs which limit their attainment in some areas (Sumida, 2010). Another major limitation of these approaches is that they label students and so risk being self-reinforcing. Labelling students as being of high potential can be enough to increase their attainment (as happened with the arbitrarily assigned ‘growth spurters’ discussed in Chapter 8), but what of those classed as not gifted? Such an approach does not offer scope for seeing giftedness as context based (all students have strengths and weaknesses) and variable over time. Teachers who have a wide range of students in their classes are expected to use differentiation; that is, having a lesson which is differentially tailored to different groups of students. Teachers can sometimes attempt to use acceleration and curriculum compacting (see Chapter 6) to move gifted students at a different pace, but this can be challenging as it makes whole-class teaching difficult. Students can, however, be set different activities in the same topic (differentiation by task), rather than simply set the same tasks with the assumption that some will be less successful (differentiation by outcome). Gifted learners can be asked to consider more demanding examples and applications than their peers. One of the characteristics of many gifted learners is that they can more readily make linkages within topics, across topics and across subjects. As science puts a high value on ideas that have wide application (e.g. the conservation of energy) and which subsume different concepts and phenomena under a single framework (e.g. Maxwell’s work showing how electricity, magnetism and radiation were linked; natural selection), gifted students can be set tasks related to finding links between topics, between the sciences and between science concepts and other curriculum areas (Taber, 2018b). These strategies can be useful, although none of these approaches offer a totally satisfactory solution that will work in every lesson.

Differentiation by support It is likely that teachers will need to respond to wide ability ranges by a combination of strategies. However, the perspective developed above, drawn from Vygotsky, suggests that

Challenging the Gifted Young Scientist (and Other Young Scientists) differentiation by support can be a useful approach. Here tasks can be designed to be challenging for the ablest students in the class, who are expected to work on them with limited support. Increasing levels of support are offered to less advanced learners (see Figure 7.5). Planning teaching here starts from designing learning activities that will engage and challenge the ablest students in the class, and then looks to how these activities may be made accessible to others in the group so that everyone experiences a challenge, yet a challenge that can be tackled with (a differentiated level of) support. Support may take the form of additional resources, or time spent with the teacher discussing the activities. However, it may also involve working in groups where the more advanced students help to support their classmates. Group work can be very effective, as long as students have already learnt group-work skills (Mercer et al., 2004). The role of the ablest students may be especially important here – as suggested above, it is possible for a group to be successful despite some of its members making little sense of what is going on (and so learning little). The ablest members of the group must appreciate that their role is not just to complete the task set on behalf of the group. Explicit assessment criteria may be useful here, so it is clear that group success will be judged in terms of all members of the group having participated meaningfully and made progress in their skills and/or understanding.

Peer tutoring Gifted students can sometimes make effective peer tutors. However, there are two important provisos. All students are unique, and some will enjoy and value teaching and supporting others, but some will not (or at least will need to be given the opportunity to ease into and become comfortable in the role). We should also not assume that a gifted learner is automatically a gifted teacher: teaching is an advanced skill that needs to be honed and developed, so students should not be pushed into this role unwillingly. The second proviso is that asking the gifted to peer tutor is not acceptable on the grounds that they have successfully completed the work and so can spend time helping others catch up. Gifted students are not free labour. Peer tutoring must be beneficial to both parties. Potentially, this can be effective. There is a saying often heard among teachers: ‘I never really understood (some topic or concept) until I started to teach it’. As a teacher, you will have realised that your knowledge and understanding of material often has to be so much greater to meet the test of a class of students than was needed to pass examinations in the subject (see Chapter 4), so the process of preparing for and engaging in teaching has helped you learn your science in much more depth. That potential is there for gifted learners as well. However, as an expert educator, you may have to scaffold their learning about teaching to facilitate their developing understanding of science through their helping to scaffold the learning of other students. Providing these conditions are met, asking gifted students to (a) take facilitating roles in group work, (b) provide remedial tuition to students who need support and (c) develop

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MasterClass in Science Education supplementary learning resources to support teaching (an authentic learning task if the intention is to develop materials that will actually be used) may be educative for them, as well as beneficial to other students. Enquiry into practice: Differentiation by support Consider a topic you are due to teach. When planning your lessons, start with a consideration of the ablest students in the class (or if you have sets, perhaps consider the students in the top set). Take into account the existing background knowledge and the capabilities of these students (do you need to undertake some diagnostic assessment to judge this?). How can you plan lesson activities that would challenge these students, and yet have the potential to move them on substantially in their learning? What scaffolding or other support would you incorporate to ensure such students could meet the challenges of the work? Now consider how you might differentiate by support, by introducing further layers and levels of support that would allow other students in the class (or students in other sets) access to success in these activities. This is by no means a straightforward matter, and a first iteration may not be well enough honed to allow all students to be both challenged and successful. If possible, try out this approach and evaluate its value as a strategy. If you find you misjudged the levels of challenge and support needed, then do you feel your classes would have been more educative for students as you had previously taught them? (That is, do you feel your previous approach to teaching this material was sufficiently challenging and yet accessible to all of the students that it was able to support them all in making progress in their learning?) Do you think this strategy will be more viable in some topics and kinds of classroom activities than others?

If you accept the challenge suggested in this chapter, and try planning your classes not from the lowest common denominator (what everyone in the class can manage) nor by seeking to ‘hit’ the median student as a best compromise (hopefully no one left too far behind, hopefully no one feeling too bored), but by seeking to look to challenge and support the students who are most advanced, and then offering differentiation by support for others, it is quite likely that you will find it very difficult to initially gauge the levels of challenge and support appropriate across the class. However, if you have not got this right by making an explicit effort to match the offered level of support to particular groups of students, then it seems likely that you will have previously (when not even seeking to differentiate support) been even further off-target. Chapter 2 considered the rationale for teaching science, and alongside such considerations of what we are trying to teach, one has to accept that classes are educative for students only when those students can benefit in relation to our curriculum aims through engaging in the learning activities we set up. If our classes lack demand, or lack the support students need, then we may look like we are teaching (cf. Figure 4.1) but we are not truly educating.

Challenging the Gifted Young Scientist (and Other Young Scientists) The fully professional science teacher approaches teaching with a scientific mentality. We try things, and sometimes we do not get everything right first (or even second) time. But by enquiring into our teaching and our students’ learning, and treating teaching as an enquirybased activity, we become better teachers and, in this way, are actively engaged in a scientific activity.

Suggested further reading Sumida, M., & Taber, K. S. (Eds.) (2017). Policy and Practice in Science Education for the Gifted: Approaches from Diverse National Contexts. Abingdon: Routledge. Taber, K. S. (Ed.) (2007). Science Education for Gifted Learners. London: Routledge.

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References Abrahams, I. (2011). Practical Work in School Science: A Minds-on Approach. London: Continuum. Abrahams, I., & Millar, R. (2008). Does Practical Work Really Work? A Study of the Effectiveness of Practical Work as a Teaching and Learning Method in School Science. International Journal of Science Education, 30(14), 1945–1969. Adúriz-Bravo, A., & Chion, A. R. (2017). Language, discourse, argumentation, and science education. In K. S. Taber & B. Akpan (Eds.), Science Education: An International Course Companion (pp. 157–166). Rotterdam: Sense Publishers. Alonzo, A. C., & Gotwals, A. W. (Eds.). (2012). Learning Progressions in Science: Current Challenges and Future Directions. Rotterdam: Sense Publishers. Ashe, G. (1987). The Discovery of King Arthur. New York: Holt. Aubrey, K., & Riley, A. (2017). A. S. Neill: Freedom to learn. In Understanding and Using Challenging Educational Theories (pp. 31–43). London: Sage. Ausubel, D. P. (2000). The Acquisition and Retention of Knowledge: A Cognitive View. Dordrecht: Kluwer Academic Publishers. Bachelard, G. (1940/1968). The Philosophy of No: A Philosophy of the Scientific Mind. New York: Orion Press. Berger, R., & Hänze, M. (2015). Impact of Expert Teaching Quality on Novice Academic Performance in the Jigsaw Cooperative Learning Method. International Journal of Science Education, 37(2), 294–320. Best, J. (2015). Breaking Bad Science. Science, 347(6222), 619. Biesta, G. J. J., & Burbules, N. C. (2003). Pragmatism and Educational Research. Lanham, MD: Rowman & Littlefield Publishers. Bloom, B. S. (1968). The cognitive domain. In L. H. Clark (Ed.), Strategies and Tactics in Secondary School Teaching: A Book of Readings (pp. 49–55). London: MacMillan. Bridges, S. A. (Ed.) (1969). Gifted Children and the Brentwood Experiment. Bath: The Pitman Press. British Educational Research Association (2018). Ethical Guidelines for Educational Research (4th Ed.). London: British Educational Research Association. Brock, R. (2017). Tacit knowledge in science education. In K. S. Taber & B. Akpan (Eds.), Science Education: An International Course Companion (pp. 133–142). Rotterdam: Sense Publishers. Broggy, J., O’Reilly, J., & Erduran, S. (2017). Interdisciplinarity and science education. In K. S. Taber & B. Akpan (Eds.), Science Education: An International Course Companion (pp. 81–90). Rotterdam: Sense Publishers. Bruner, J. S. (1960). The Process of Education. New York: Vintage Books. Chang, H. (2012). Is Water H2O? Evidence, Realism and Pluralism. Dordrecht: Springer. Coffield, F., Moseley, D., Hall, E., & Ecclestone, K. (2004). Should We Be Using Learning Styles? What Research Has to Say to Practice. London: Learning and Skills Research Centre. Cromer, A. (1997). Connected Knowledge: Science, Philosophy and Education. Oxford: Oxford University Press.

References Csikszentmihalyi, M. (1997). Creativity: Flow and the Psychology of Discovery and Invention. New York: HarperPerennial. Darwin, C. (1859/1968). The Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life. Harmondsworth: Penguin Books. Darwin, C. (1871/2006). The descent of man, and selection in relation to sex. In E. O. Wilson (Ed.), From So Simple a Beginning: The Four Great Books of Charles Darwin (pp. 767–1248). New York: W. W. Norton & Company. Darwin, C., & Wallace, A. R. (1858). On the Tendency of Species to Form Varieties; and on the Perpetuation of Varieties and Species by Natural Means of Selection. Proceedings of the Linnean Society, 3, 45–62. Dawkins, R. (1988). The Blind Watchmaker. Harmondsworth: Penguin Books. Dehaene, S., Changeux, J.-P., Naccache, L., Sackur, J., & Sergent, C. (2006). Conscious, Preconscious, and Subliminal Processing: A Testable Taxonomy. Trends in Cognitive Sciences, 10(5), 204–211. Driver, R. (1983). The Pupil as Scientist? Milton Keynes: Open University Press. Edwards, D., & Mercer, N. (1987). Common Knowledge: The Development of Understanding in the Classroom. London: Routledge. Einstein, A. (1905). On the Motion of Small Particles Suspended in Liquids at Rest Required by the Molecular-Kinetic Theory of Heat. Annalen der Physik, 17, 549–560. Ericsson, K. A., Chase, W. G., & Faloon, S. (1980). Acquisition of a Memory Skill. Science, 208(4448), 1181–1182. Freeman, B., Marginson, S., & Tytler, R. (2015). Widening and deepending the STEM effect. In B. Freeman, S. Marginson, & R. Tytler (Eds.), The Age of STEM: Educational Policy and Practice Across the World in Science, Technology, Engineering and Mathematics (pp. 1–21). Abingdon: Routledge. Gardner, M. R. (1979). Realism and Instrumentalism in 19th-Century Atomism. Philosophy of Science, 46(1), 1–34. Geertz, C. (1973). Thick description: Toward an interpretive theory of culture. In The Interpretation of Cultures: Selected Essays (pp. 3–30). New York: Basic Books. Gilbert, J. K., Osborne, R. J., & Fensham, P. J. (1982). Children’s Science and Its Consequences for Teaching. Science Education, 66(4), 623–633. Goldman, A. (1995). Knowledge. In T. Honderich (Ed.), The Oxford Companion to Philosophy (pp. 447–448). Oxford: Oxford University Press. Goldstone, R. L., & Day, S. B. (2012). Introduction to “New Conceptualizations of Transfer of Learning”. Educational Psychologist, 47(3), 149–152. Hesse, M. B. (1959). On Defining Analogy. Proceedings of the Aristotelian Society, 60, 79–100. Hodson, D. (2014). Nature of science in the science curriculum: Origin, development, implications and shifting emphases. In M. R. Matthews (Ed.), International Handbook of Research in History, Philosophy and Science Teaching (pp. 911–970). Dordrecht: Springer. Holbrook, J., & Rannikmae, M. (2017). Context-based teaching and socio-scientific issues. In K. S. Taber & B. Akpan (Eds.), Science Education: An International Course Companion (pp. 279–294). Rotterdam: Sense Publishers. Huxley, T. H. (1889). Agnosticism. The Nineteenth Century, February, 130. Jewitt, C., Kress, G., Ogborn, J., & Tsatsarelis, C. (2001). Exploring Learning through Visual, Actional and Linguistic Communication: The Multimodal Environment of a Science Classroom. Educational Review, 53(1), 5–18.

223

224

References Johnson, S. (1989). National Assessment: The APU Science Approach. London: Assessment of Performance Unit. Johnstone, A. H. (1982). Macro- and Microchemistry. School Science Review, 64(227), 377–379. Kember, D. (1991). Instructional Design for Meaningful Learning. Instructional Science, 20, 289–310. Keogh, B., & Stuart, N. (1999). Concept Cartoons, Teaching and Learning in Science: An Evaluation. International Journal of Science Education, 21(4), 431–446. Kerry, T., & Kerry, C. A. (1997). Differentiation: Teachers’ Views of the Usefulness of Recommended Strategies in Helping the More Able Pupils in Primary and Secondary Classrooms. Educational Studies, 23(3), 439–457. Kind, P. M., & Kind, V. (2007). Creativity in Science Education: Perspectives and Challenges for Developing School Science. Studies in Science Education, 43(1), 1–37. Kind, V. (2009). Pedagogical Content Knowledge in Science Education: Perspectives and Potential for Progress. Studies in Science Education, 45(2), 169–204. Kirschner, P. A., Sweller, J., & Clark, R. E. (2006). Why Minimal Guidance During Instruction Does Not Work: An Analysis of the Failure of Constructivist, Discovery, Problem-Based, Experiential, and InquiryBased Teaching. Educational Psychologist, 41(2), 75–86. Kitzmiller et al. v. Dover Area School District et al. (2005). United States Court for the Middle District of Pennsylvania, Case No. 04cv2688. Klahr, D. (2009). ‘To every thing there is a season, and a time to every purpose under the heavens’: What about direct instruction? In S. Tobias & T. M. Duffy (Eds.), Constructivist Instruction: Success or Failure? (pp. 291–310). New York: Routledge. Knorr Cetina, K. (1999). Epistemic Cultures: How the Sciences Make Knowledge. Cambridge, MA: Harvard University Press. Krathwohl, D. R., Bloom, B. S., & Masia, B. B. (1968). The affective domain. In L. H. Clark (Ed.), Strategies and Tactics in Secondary School Teaching: A Book of Readings (pp. 41–49). New York: The Macmillan Company. Kuhn, T. S. (1996). The Structure of Scientific Revolutions (3rd ed.). Chicago: University of Chicago. Lakatos, I. (1970). Falsification and the methodology of scientific research programmes. In I. Lakatos & A.  Musgrove (Eds.), Criticism and the Growth of Knowledge (pp. 91–196). Cambridge: Cambridge University Press. Lakoff, G., & Johnson, M. (1980). Metaphors We Live by. Chicago: University of Chicago Press. Leach, J., & Scott, P. (2002). Designing and Evaluating Science Teaching Sequences: An Approach Drawing Upon the Concept of Learning Demand and a Social Constructivist Perspective on Learning. Studies in Science Education, 38, 115–142. Lederman, N. G., & Lederman, J. S. (2012). Nature of scientific knowledge and scientific inquiry: building instructional capacity through professional development. In B. J. Fraser, K. G. Tobin & C. J. McRobbie (Eds.), Second International Handbook of Science Education (pp. 335–359). Dordrecht: Springer. Long, D. E. (2011). Evolution and Religion in American Education: An Ethnography. Dordrecht: Springer. Luria, A. R. (1987). The Mind of a Mnemonist. Cambridge, MA: Harvard University Press. Lyons, T. (2006). Choosing physical science courses: The importance of cultural and social capital in the enrolment decisions of high achieving students. In R. Janiuk & E. Samonek-Miciuk (Eds.), Science and Technology Education for a Diverse World: Dilemmas, Needs and Partnerships. (pp. 369–384). Lublin: Marie Curie-Sklodowska University Press.

References Marek, E. A. (2009). Genesis and evolution of the learning cycle. In W.-M. Roth & K. Tobin (Eds.), Handbook of Research in North America (pp. 141–156). Rotterdam: Sense Publishers. Maslow, A. H. (1948). ‘Higher’ and ‘Lower’ Needs. The Journal of Psychology, 25, 433–436. McIntyre, D., Peddar, D., & Ruddock, J. (2005). Pupil Voice: Comfortable and Uncomfortable Learnings for Teachers. Research Papers in Education, 20(2), 149–168. McLachlan, J. (1990). Joseph Priestley and the Study of History. Transactions of the Unitarian Historical Society, 19(4), 252 (cited at https://en.wikipedia.org/wiki/Joseph_Priestley). Mercer, N., Dawes, L., Wegerif, R., & Sams, C. (2004). Reasoning as a Scientist: Ways of Helping Children to Use Language to Learn Science. British Educational Research Journal, 30(3), 359–377. Mortimer, E. F., & Scott, P. H. (2003). Meaning Making in Secondary Science Classrooms. Maidenhead: Open University Press. Nash, R. (1990). Bourdieu on Education and Social and Cultural Reproduction. British Journal of Sociology of Education, 11(4), 431–447. National Research Council Committee on Scientific Principles for Educational Research (2002). Scientific Research in Education. Washington, DC: National Academies Press. Nickerson, R. S. (1998). Confirmation Bias: A Ubiquitous Phenomenon in Many Guises. Review of General Psychology, 2(2), 175–220. Palmer, D. (1997). The Effect of Context on Students’ Reasoning about Forces. International Journal of Science Education, 19(16), 681–696. Piaget, J. (1970/1972). The Principles of Genetic Epistemology (W. Mays, Trans.). London: Routledge & Kegan Paul. Piaget, J., & Garcia, R. (1989). Psychogenesis and the History of Science (H. Feider, Trans.). New York: Columbia University Press. Popper, K. R. (1934/1959). The Logic of Scientific Discovery. London: Hutchinson. Popper, K. R. (1989). Conjectures and Refutations: The Growth of Scientific Knowledge (5th ed.). London: Routledge. Rennie, L. J., Venville, G., & Wallace, J. (2012). Knowledge that Counts in a Global Community: Exploring the Contribution of Integrated Curriculum. Abingdon: Routledge. Roberts, D. A., & Bybee, R. W. (2014). Scientific literacy, science literacy, and science education. In N. G. Lederman & S. K. Abell (Eds.), Handbook of Research on Science Education (Vol. 2, pp. 545–558). New York: Routledge. Rosenthal, R., & Jacobson, L. (1968). Pygmalion in the Classroom: Teacher Expectation and Pupils’ Intellectual Development. New York: Holt, Rinehart & Winston. Ruthven, K., Mercer, N., Taber, K. S., Guardia, P., Hofmann, R., Ilie, S., et al. (2017). A Research-Informed Dialogic-Teaching Approach to Early Secondary School Mathematics and Science: The Pedagogical Design and Field Trial of the epiSTEMe Intervention. Research Papers in Education, 32(1), 18–40. Savinainen, A., & Scott, P. (2002). Using the Force Concept Inventory to Monitoring Student Learning and to Plan Teaching. Physics Education, 37(1), 53–58. Schwab, J. J. (1962). The teaching of science as enquiry (The Inglis Lecture, 1961). In J. J. Schwab & P. F. Brandwein (Eds.), The Teaching of Science. Cambridge, MA: Harvard University Press. Scott, P. (1998). Teacher Talk and Meaning Making in Science Classrooms: A Review of Studies from a Vygotskian Perspective. Studies in Science Education, 32, 45–80. Shayer, M., & Adey, P. (1981). Towards a Science of Science Teaching: Cognitive Development and Curriculum Demand. Oxford: Heinemann Educational Books.

225

226

References Silver, C. (2008). On the Origin of Fairies: Victorians, Romantics, and Folk Belief. Browning Institute Studies, 14, 141–156. Smith, A. (1827/1981). An Inquiry into the Nature and Causes of the Wealth of Nations (W. B. Todd Ed.). Indianapolis, IN: Liberty Classics. Snow, C. P. (1959/1998). The Rede Lecture, 1959: The two cultures. In The Two Cultures (pp. 1–51). Cambridge: Cambridge University Press. Stamovlasis, D., & Tsaparlis, G. (2000). Non-linear Analysis of the Effect of Working-memory Capacity on Organic-Synthesis Problem Solving. Chemistry Education Research and Practice, 1(3), 375–380. Stuckey, M., Hofstein, A., Mamlok-Naaman, R., & Eilks, I. (2013). The Meaning of ‘Relevance’ in Science Education and Its Implications for the Science Curriculum. Studies in Science Education, 49(1), 1–34. Sumida, M. (2010). Identifying Twice-Exceptional Children and Three Gifted Styles in the Japanese Primary Science Classroom. International Journal of Science Education, 15(1), 2097–2111. Sumida, M. (2013). The Japanese view of nature and its implications for the teaching of science in the early childhood years. In J. Georgeson & J. Payler (Eds.), International Perspectives on Early Childhood Education and Care (p. 243). Maidenhead: Open University Press. Sumida, M. (2018). STEAM (science, technology, engineering, agriculture, and mathematics) education for gifted young children: A glocal approach to science education for gifted young children. In K. S. Taber, M. Sumida & L. McClure (Eds.), Teaching Gifted Learners in STEM Subjects: Developing Talent in Science, Technology, Engineering and Mathematics (pp. 223–241). Abingdon: Routledge. Taber, K. S. (1991). Girl-friendly Physics in the National Curriculum. Physics Education, 26(4), 221–226. Taber, K. S. (1994). Misunderstanding the Ionic Bond. Education in Chemistry, 31(4), 100–103. Taber, K. S. (1998). An Alternative Conceptual Framework from Chemistry Education. International Journal of Science Education, 20(5), 597–608. Taber, K. S. (2000). Finding the Optimum Level of Simplification: The Case of Teaching about Heat and Temperature. Physics Education, 35(5), 320–325. Taber, K. S. (2001). Building the Structural Concepts of Chemistry: Some Considerations from Educational Research. Chemistry Education: Research and Practice in Europe, 2(2), 123–158. Taber, K. S. (2002). Chemical Misconceptions – Prevention, Diagnosis and Cure. London: Royal Society of Chemistry. Taber, K. S. (2007a). Enriching School Science for the Gifted Learner. London: Gatsby Science Enhancement Programme. Taber, K. S. (2007b). Science education for gifted learners? In K. S. Taber (Ed.), Science Education for Gifted Learners (pp. 1–14). London: Routledge. Taber, K. S. (2009). Progressing Science Education: Constructing the Scientific Research Programme into the Contingent Nature of Learning Science. Dordrecht: Springer. Taber, K. S. (2011a). Constructivism as educational theory: Contingency in learning, and optimally guided instruction. In J. Hassaskhah (Ed.), Educational Theory (pp. 39–61). New York: Nova. Retrieved from http://people.ds.cam.ac.uk/kst24/KeithSTaber/Constructivism.html. Taber, K. S. (2011b). The natures of scientific thinking: Creativity as the handmaiden to logic in the development of public and personal knowledge. In M. S. Khine (Ed.), Advances in the Nature of Science Research – Concepts and Methodologies (pp. 51–74). Dordrecht: Springer. Taber, K. S. (2013a). Classroom-based Research and Evidence-based Practice: An Introduction (2nd ed.). London: Sage.

References Taber, K. S. (2013b). A common core to chemical conceptions: Learners’ conceptions of chemical stability, change and bonding. In G. Tsaparlis & H. Sevian (Eds.), Concepts of Matter in Science Education (pp. 391–418). Dordrecht: Springer. Taber, K. S. (2013c). Conceptual frameworks, metaphysical commitments and worldviews: The challenge of reflecting the relationships between science and religion in science education. In N. Mansour & R. Wegerif (Eds.), Science Education for Diversity: Theory and Practice (pp. 151–177). Dordrecht: Springer. Taber, K. S. (2013d). Modelling Learners and Learning in Science Education: Developing Representations of Concepts, Conceptual Structure and Conceptual Change to Inform Teaching and Research. Dordrecht: Springer. Taber, K. S. (2013e). Revisiting the Chemistry Triplet: Drawing upon the Nature of Chemical Knowledge and the Psychology of Learning to Inform Chemistry Education. Chemistry Education Research and Practice, 14(2), 156–168. Taber, K. S. (2013f). Upper Secondary Students’ Understanding of the Basic Physical Interactions in Analogous Atomic and Solar Systems. Research in Science Education, 43(4), 1377–1406. Taber, K. S. (2014). Student Thinking and Learning in Science: Perspectives on the Nature and Development of Learners’ Ideas. New York: Routledge. Taber, K. S. (2015a). Epistemic relevance and learning chemistry in an academic context. In I. Eilks & A.  Hofstein (Eds.), Relevant Chemistry Education: From Theory to Practice (pp. 79–100). Rotterdam: Sense Publishers. Taber, K. S. (2015b). Meeting educational objectives in the affective and cognitive domains: Personal and social constructivist perspectives on enjoyment, motivation and learning chemistry. In M. Kahveci & M. Orgill (Eds.), Affective Dimensions in Chemistry Education (pp. 3–27). Berlin: Springer. Taber, K. S. (2017). Teaching and learning chemistry. In K. S. Taber & B. Akpan (Eds.), Science Education: An International Course Companion (pp. 325–341). Rotterdam: Sense Publishers. Taber, K. S. (2018a). The End of Academic Standards? A Lament on the Erosion of Scholarly Values in the Post-truth World. Chemistry Education Research and Practice, 19(1), 9–14. Taber, K. S. (2018b). Knowledge sans frontières? Conceptualising STEM in the curriculum to facilitate creativity and knowledge integration. In K. S. Taber, M. Sumida & L. McClure (Eds.), Teaching Gifted Learners in STEM Subjects: Developing Talent in Science, Technology, Engineering and Mathematics (pp.  1–19). Abingdon: Routledge. Taber, K. S., & Tan, K. C. D. (2011). The Insidious Nature of ‘Hard Core’ Alternative Conceptions: Implications for the Constructivist Research Programme of Patterns in High School Students’ and Preservice Teachers’ Thinking about Ionisation Energy. International Journal of Science Education, 33(2), 259–297. Taber, K. S., & Watts, M. (1996). The Secret Life of the Chemical Bond: Students’ Anthropomorphic and Animistic References to Bonding. International Journal of Science Education, 18(5), 557–568. Taber, K. S., de Trafford, T., & Quail, T. (2006). Conceptual Resources for Constructing the Concepts of Electricity: The Role of Models, Analogies and Imagination. Physics Education, 41, 155–160. Taber, K. S., Billingsley, B., Riga, F., & Newdick, H. (2011). Secondary Students’ Responses to Perceptions of the Relationship between Science and Religion: Stances Identified from an Interview Study. Science Education, 95(6), 1000–1025. Taber, K. S., Tsaparlis, G., & Nakiboğlu, C. (2012). Student Conceptions of Ionic Bonding: Patterns of Thinking across Three European Contexts. International Journal of Science Education, 34(18), 2843–2873.

227

228

References Taber, K. S., Ruthven, K., Howe, C., Mercer, N., Riga, F., Hofmann, R., & Luthman, S. (2015). Developing a research-informed teaching module for learning about electrical circuits at lower secondary school level: supporting personal learning about science and the nature of science. In E. De Silva (Ed.), Cases on Research-Based Teaching Methods in Science Education (pp. 122–156). Hershey, PA: IGI Global. Taber, K. S., Ruthven, K., Mercer, N., Riga, F., Luthman, S., & Hofmann, R. (2016). Developing Teaching with an Explicit Focus on Scientific Thinking. School Science Review, 97(361), 75–84. Thagard, P. (1992). Conceptual Revolutions. Chichester: Princeton University Press. Tobias, S., & Duffy, T. M. (Eds.). (2009). Constructivist Instruction: Success or Failure? New York: Routledge. Tomlinson, P. (1989). Having It Both Ways: Hierarchical Focusing as Research Interview Method. British Educational Research Journal, 15(2), 155–176. Tripp, D. (2005). Action Research: A Methodological Introduction. Educação e Pesquisa, 31(3), 443–466. Vygotsky, L. S. (1978). Mind in Society: The Development of Higher Psychological Processes. Cambridge, MA: Harvard University Press. White, R. T., & Gunstone, R. F. (1992). Probing Understanding. London: Falmer Press. Whitehead, J. (1989). Creating a Living Educational Theory from Questions of the Kind, ‘How Do I Improve My Practice?’ Cambridge Journal of Education, 19(1), 41–52. Windelbrand, W. (1894/1980). History and Natural Science: Rectorial Address, Strasbourg, 1894. History and Theory, 19(2), 169–185. Wolpert, L. (1992). The Unnatural Nature of Science. London: Faber & Faber.

Index Abraham, Ian 207, 208 abstraction 59, 81, 84, 101, 187 acceleration (in learning) 218 action research 204, 205 activation energy 61 Adam and Eve 153 advance organiser 106, 119 aesthetics 30, 31, 32 affective domain 30 age of the earth 57 agnosticism 156–7 allotropy/allotropes of tin 63 alternative conceptions 8, 13, 38, 59, 66, 78, 83, 99, 101–5, 111, 148, 168, 174, 179, 182, 186 about the nature of quanticles 185–6 and historical scientific conceptions 66, 186 and PCK 76 as learning impediments 99–100 as plausible mental constructions 99 characteristics/dimensions of 98, 101–3 diagnosing 103–5 reinforced by teaching 59, 74 alternative frameworks 102 ambiguous terms 46 analogy 59, 61, 62, 65, 76, 80, 107, 122 as a teaching move 107 atom & solar system 62 brain and computer 80–3 for electrical current 200–1 STEM pipeline 27 training wheels 65 analysing teaching 107–9 anthropomorphism 64–5, 101 strong 64 weak 64, 65 argumentation 34, 90, 113, 123–4, 157, 173, 183, 209 and evidence 52, 123, 144, 149–50 circular 90 God of the gaps 154–5 ideological 13 in philosophy 10, 163

in teaching 113, 190 justification 49 Aristotle 10–11, 33 ascorbic acid 176–7 aspirational driver for teaching science 26, 28 assessment 8–9, 76, 107, 121–2, 198–9, 215–6 as a learning opportunity 104, 105, 123 criteria 219 diagnostic 11, 78, 86, 103–8, 125, 220 formative 78, 103–4, 123, 125 in ZPD 123, 215–17 risk 184 summative (terminal) 83, 103 Association for Science Education 197 assumptions informing teaching 10, 60, 70, 99, 110, 193 atheism 156, 158 atomic models 105 atomic orbitals 105, 181 atomic theory 178 atoms 57, 59, 62, 64, 65, 89, 90, 100–2, 178–86 as sentient agents 64–5, 100 structure 105 attitudes to science 30, 43 Augustine 153 Ausubel, David 90, 106, 119 authoritative teaching 123–4, 201 autodidacts 214 bacterial flagellum 154 Bad Science 158 banding 111, 192, 218 batteries 47, 64, 192 Beagle, the 164 beauty 30, 57 belief 48, 49, 51–5, 71, 91, 95, 96, 128, 129, 130, 145, 147–61, 164, 166, 169, 172, 174 and knowledge 48–55, 95, 145 effect of 129–30, 152–3 bias 13, 73, 80, 83, 84, 128, 130, 142, 150, 170 in cognition 80, 83–4, 128 in experimental studies of teaching 197–8

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Index in science 13 in teaching 73, 130, 142, 150–2, 170–2 Big Bang 147, 155 Big Bang Theory, the 30 Bildung 31 bird’s nest 63 black boxes 196 Bloom’s taxonomies 30, 74, 78 bonding 101 hydrogen 88 ionic 64 bootstrapping 88–90, 92 brain as computer analogy 56, 80, 83 brain in a vat 56 bridging levels of explanation 187–90 Brownian motion 179 Bruner, Jerome 90, 192, 193, 196 Bruno, Giordano 179 busy (as opposed to productive) work 216 career decisions 37–8 case study 12, 130, 135, 205 case studies-value of 130 category errors 158 cells ambiguity 46 biological 56, 61, 105, 115, 148 electrochemical 47, 191–2 centrifugal force 51 changes of state 176–8 chemical bonds 100, 101, 102 chemical formulae 187–90 chemical reaction 51, 89–90, 102, 148–9, 176, 185–9, 192 Chemistry Education Research and Practice 16 chemist’s triplet, the 186–90 choice (in learning) 31, 32, 34, 37–40, 43, 70, 73, 113, 116, 117, 158, 195, 205 choice argument for teaching science 26 chunks/chunking of information (in relation to human cognition) 76, 80–3, 85, 109, 168, 187, 210 citizenship argument for teaching science 26 citizenship, science for 31–4, 204 climate change 34, 96, 151 cognition 57, 79, 80, 86 cognitive development 109 domain 30, 74 load 187 skills 75, 91, 93, 204, 211

combustion 49, 51, 52, 186 commitment to conceptions 102 communication skills 39 compacting of curriculum 218 compartmentalisation of knowledge 35 compound 81, 87–9, 148, 176–7, 187–8 concept 9, 46, 78, 86, 88, 107, 177–8, 186–7, 192–3, 208–9 abstract 113–15, 189 analysing 86–8, 105 bootstrapping 88–9 cartoons 124–5 couple (of a) 116–18 inventory 104 knowledge as a concept 48 map 86–7 misunderstood 7 prerequisite. See prerequisite, knowledge structure 86 concept cartoons 125 concept mapping 86–7 conceptions 71–3, 99, 101, 103, 138, 151, 168, 191 conceptual analysis 86–9, 105, 192 conceptual frameworks 98, 101, 144, 168, 186 conceptual integration 98, 102, 187, 201, 218 conceptual resources 91 conceptual structure 86, 187 conceptual tools 187 conceptual vacuum 124 concrete operational thinking 87 conditions for learning 109–10, 113 conduction 105, 192 confirmation bias 128, 142 conjectures 138, 140, 142, 211 consolidation (of memory) 186, 193 constants in science 56–7 constructionism 27, 66, 140, 160, 212 constructivism/constructivist position 27, 79, 83, 86–93, 112–13 constructivist 79, 83 personal 27 social 27 teaching 86–93, 112, 113 context-based learning 75 context-directed research 131 context, effect on learning outcomes 13–14, 18, 73–4, 130, 193 context-importance of 19, 37, 43, 78 context, in language 47, 75 context, of teaching and learning 130 context, teaching science in 34–40, 75–6, 85, 122, 212

Index control group 128 control conditions 123, 128–30, 197–9 Copernicus, Nicolaus 179 copyright 19–20 couple 113, 116–19, 209 couple-teaching concept 116, 117 creativity 42, 52, 64, 105, 108, 127, 140, 178 Crick, Francis 165 critical friends 125, 126 critical thinking 9, 13, 54, 64, 158, 173, 184, 204, 211 cross-disciplinary team teaching 40 cultural capital 38 driver for teaching science 26, 29 innovation 40 norms 42 tools in learning 116 culture, reproduction of 31, 40 curiosity 148 curriculum 5, 6, 25–43, 73, 76, 105, 113, 114, 171, 172, 191–6, 203, 204, 218, 220 acceleration 216 compaction 104–5, 218 integration 40–1, 184 models 98 spiral 75, 90, 105, 193–5 Dalton, John 92, 178 Darwin, Charles 90, 92, 103, 156, 164–7, 170, 173 data, and evidence 171 Dawkins, Richard 154, 157 deduction 50, 63, 89, 138, 140, 144, 182 deism 156 democratic driver for teaching science 26, 31 Democritus 178, 186 demonstration 76, 105, 109, 124, 137 dephlogisticated air 52 Descent of Man, the 165 developmental driver for teaching science 26 diagnostic assessment 17, 18, 86, 103–6, 122, 125 diagrams 19, 60, 107, 109, 116, 117, 119, 184, 195 dialectical nature of science 114, 212 dialogic teaching 91, 104, 108, 123–6, 184, 200, 214 differentiation of teaching 111–12, 118–19, 126, 214, 218 by outcome 218 by support 218–20 by task 218 diffraction 181 dinosaurs 151, 171 direct instruction 111, 112–14

discourse 46, 47, 96, 111, 114, 205 discovery learning 112–15, 205–6 disease 70, 96, 171 dissection 30, 152 diversity of students 12, 99–103, 111–12, 214 DNA 96–7, 165 dogmatic approach to teaching scientific accounts 173 double-blind trials 128–9 double science 28 doubly exceptional learners 218 drivers motivating curriculum choices 34 drugs trial(s) 46–7, 128 Economic and Social Research Council 197 economic driver for teaching science 26, 27, 30 educational experiment 129–30 educative provision 215–18 educative teaching 105, 111, 115, 215, 220 Einstein, Albert 50, 51, 53, 142, 179 electrical circuits 59, 61, 191–201 electromagnetic radiation 50 electrons as waves 149, 181 element 47, 51, 57, 58, 88–90, 176, 187–8 in chemistry 47, 51, 88, 89, 90, 121, 176, 187, 188 water as a 47 elephants 167 eliciting student conceptions 124–5 embeddedness of conceptions 102 enculturation 15, 30–1, 36, 150, 171 enquiry/inquiry learning 47, 112, 114, 201, 203–12 enquiry skills 204, 211 epiphenomenon 63 episteme 11, 33 epiSTEMe (Effecting Principled Improvement in STEM Education) project 197–201 epistemic 11, 33 hunger 148, 184 relevance 148, 178, 185, 201, 211, 212 epistemology 47, 55, 72, 119–20, 138 genetic 92 ethical considerations 19 ethical enquiry 12–13 ethnography 71, 205 evidence-based practice/teaching 10, 14, 19 evidence, and data 171 evidence for knowledge claims 10 evidence (in science) 10, 13, 34, 52, 54, 123, 143–4, 150–60, 170–3, 203, 211 and self-correction 58, 95–7 underdetermining conclusions 136–7

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Index evil spirit 151, 171 evolution 73, 92, 96, 100–3, 115, 150–60, 163–74 examination specifications 9, 74, 108, 113, 183 expectancy effects 42, 128–9, 141, 215 experiment(s) 50, 56, 76, 105, 115, 116, 124, 125, 129–30, 137, 143, 177, 203, 205. See also thought experimentation cf. philosophy 163 evaluating teaching 76, 127, 129–30, 197 in science 124, 140, 143–4 undertaken by students 137, 203–6 explanation in science 5, 38, 95–106 explanation, scientific 38, 53, 148, 168–9, 178, 189, 212 alternative 57 circular 181–2 constructing 122, 216 from laws 166 natural 55–7, 155, 157, 173 extra-scientific values 32 factors influencing learning 126–30 facts 114, 115 fading (of support/scaffolding) 75, 119–20, 217 F-a {force-acceleration} thinking 100 fairies-belief in 149, 166, 169 fair testing when evaluating teaching innovations 81–2 fall, the 153 falsification 140–2, 144 familiarisation in learning 64, 75, 83, 168, 187, 195–6, 205, 210 in teaching 128 figurative language 61 figures of speech 61–2, 64 Fleming’s hand rules 60 flipped learning 75 flow (mental state) 111, 217 flow experiences 111, 217 focus groups 27, 37, 78 force and motion 100 force concept inventory 104 formal operational thinking 87, 93 formulae equation 188 formative assessment 103, 104, 111, 123, 125–6 free schools 113 freezing temperature 177 full outer shells explanatory principle 102 fully professional science teacher 3, 10, 20, 126, 221 F-v {force-velocity} thinking 100

Galilei, Galileo 50, 153 gatekeepers in research 20 Gatsby Charitable Foundation 197 gender issues 41–2 gene transposition 51, 52 genes 50, 53, 167 jumping 50, 53 genetic epistemology 92 genetics 5, 17, 30, 76, 150, 165, 192 genius 92, 165, 214 geocentric model 179 gesture 60, 109 gifted and talented, the 213 gifted, the 213, 214, 218, 219 giftedness 180, 185, 213–21 girls’ under-representation in some STEM areas 41–2 glass 177–8, 186 God 55, 56, 152, 153, 155–9, 160, 164, 171 God of the gaps 155 Goldacre, Ben 158 good life, the 204 Google scholar 17 gravity/gravitation 51–4, 57–8, 62, 88, 115, 160, 166 The great flood 153, 171 group interviews 37 group work 105, 118–19, 124, 144, 184, 200–1, 219–20 composition of group 214, 216 projects 39 roles in 39, 219 group-work skills 219 growth spurters (Pygmalion effect) 129, 218 guided discovery 113, 114 heliocentric model 179 hierarchical focusing 37, 208 Higgs boson-evidence for 143, 149 high energy physics 143, 151 higher level cognitive skills 75, 121 highly able, the 213 Huxley, Thomas 156 hydrogen bonding 88 hypothesis 46, 97, 127, 141 hypothetico-deductive method 140–2, 144 Identity (as a science teacher) 4 ideographic research 27, 136 ideology 13 idiographic enquiry 27, 136

Index imagination in learning 113, 140, 167, 178, 211 in planning teaching 110–11 in science 31, 51, 52, 91, 97, 155, 160, 174 imaginative leap-in learning 91 impetus framework 102, 103 impetus theory 100, 102–3 independent events 139 individual interviews 37 indoctrination 31 induction 31, 91, 137–40, 144 inert gases. See noble gases inheritance of acquired characteristics 169 Initiation-Response-Evaluation 75, 89, 111 Insight 20, 25, 52, 62, 92, 113 Institute of Physics 7, 197 institutional inertia 40 instrumental model or theory 178–9 instrumentation 48–9, 104, 129–30, 136, 197, 211 theory of 142–3, 151, 164, 170, 179 integrated studies 41 integration (mental processing) 40, 52 intelligence 45, 48, 111, 214 intelligent design 154–5, 158 interpretivism 27, 71 interpretivist enquiry 27 interviewing students 209 interviews 7, 27, 37, 72, 97, 168, 190, 208–9 in depth 209 prompts 37 stimulated recall 190 with groups 37 intuitive/intuition 23, 25, 48, 50, 52, 100, 101, 103, 123, 136, 143, 156 science as counter-intuitive 50–1, 208, 212 intuitive theories 99, 100 inventories of concepts 104 ionic bonding 64 IQ 111, 214 IRE patterns of classroom talk 75, 98, 111 Jesus 62 jigsaw learning activities 39 jigsaw teaching technique 39 Johnstone, Alex 186, 187 jumping genes 50–1 kinetic theory 144, 177, 179 King Crimson album titles (‘Court-Wake-LizardIslands-Larks-Starless-Red’) 81

knowledge 11, 33, 48–50, 95–99 as generalisable 130, 135 as plausible mental constructions 98, 99 compartmentalisation 35 integrated 81 pedagogic 73–8 pedagogic content (PCK) 75–7, 198 prerequisite/prior 80, 82–3, 85, 87, 91, 104–5, 118–19, 183, 192, 195, 210 public 204 reliable 54, 135, 145, 163 scientific 45–67, 91, 135–45, 151, 173 subject knowledge 5–8, 69–78, 126, 168 labelling students 218 laboratory skills 204 laboratory work 39, 74, 113, 143, 184, 204, 207–8, 210 Lakatos, Imre 92 Lamarckism 100, 103 Lamarckian model of evolution 100 language 45–8, 59, 60, 61, 64–6, 75, 80, 96, 97, 101, 110, 116, 144, 163, 179, 187, 208 anthropomorphic 64–5, 101 body 110 figurative 61, 165 informal 55 limiting learning 59 modelling scientific 66 language, technical 66 language used in teaching 101 large-scale randomised trials 130 Lavoisier, Antoine 51–2, 98 Lavoisier, Marie-Anne Paulze 51 leadership, in science teaching 20 learner’s resolution, the 82–3 learning as iterative 86, 193 cycle 65 demand 192, 193 doctor, teacher as 12 objectives 11, 43, 70, 74, 76, 122, 196, 198, 201 progression 193 quanta 76, 79–93, 109, 168 style 39 lesson activity 37–9, 72–3, 105, 106, 107–20, 124–6, 184–5, 201, 205, 210–12, 216–19 lesson plans 39, 73, 108, 125 liberal argument for teaching science 26 liberal education 29, 30, 31 long-term memory 84, 85, 86 Luria, Alexander 80, 81, 85

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Index macroevolution 100, 147, 155, 167, 168, 169, 170, 171 making the unfamiliar familiar 61, 64–5, 80, 91, 102 manipulative skills 30, 210–11 Maslow’s hierarchy of needs 75, 126 materialism 55 materials (cf. substances) 176, 178 mathematics 9, 30, 34, 40, 41, 42, 197, 214 in science 9, 34–5, 42 McClintock, Barbara 50, 51, 52 McCormick, Robert 164 meaningful learning 85, 90–1, 111 measurement error 48, 136, 143 mediation in learning 129, 150, 170 melting temperature 177 memory 79, 80–5, 119, 168, 187, 210 as representation, not storage 84 long-term 83–5, 210 working 35, 80, 85, 119, 168, 187, 210 Mendel’s laws 165 mental model 110, 111 mental register 47, 48 mentoring 42, 125, 126 metabolism 148 metacognition 109 metaphor 27, 46, 61, 65–6, 76, 109–10, 154 and anthropomorphism 101 metaphysical commitments 54, 55, 56–7 materialism 55 naturalism 156 methodological materialism 55 naturalism 156 methodology 12, 130 microscopes 52 electron 151, 179 optical 178–80 scanning tunnelling 179, 181 minds-off activity 210 minds-on learning 76 misconceptions. See alternative conceptions mixtures 47, 89, 176–8, 188 modelling 195–6, 200, 212 language 66 models 9, 34, 39, 53, 59, 60, 64, 66, 70, 75, 76, 84, 91, 96, 97, 100, 105, 110, 111, 114, 147, 151, 160, 175–90, 192, 195, 196, 201, 208, 212 analogical 59 folk 83 mental 84, 87, 110–1 of cognition/learning 88, 92, 110–11 particle 9, 59, 178–90, 192

scientific 34, 53, 58, 66, 96, 97–8, 100, 105, 143, 160, 165, 195, 200–1, 212 teaching 59, 64–6, 91, 98, 102 molecules 144, 179–81, 187–90 alternative conceptions of 59, 65, 101, 112 moral imperative 105 multidisciplinary 196 multi-modal teaching 60 multiplicity of conceptions 102 myths 62, 149, 171 narrative(s) 62–6, 109, 149, 153, 154, 155, 169, 196 natural attitude, the 142, 168 history 164, 171 philosophy 10, 163 natural philosophy 10, 163 natural selection 56, 73, 87, 96, 100–1, 152–7, 160, 163–74, 218 as creative 178 importance of teaching about 9–10, 135 misrepresenting 58, 174 misunderstandings of 54 reflecting in teaching 90, 144, 173–4, 178, 184, 212 teaching 198, 201 natural theology 55 naturalism 155 metaphysical 156–9 methodological 156–7 nature of science, the 9, 10, 54, 58, 90, 95, 135–45, 184, 198, 201, 212 neo-Darwinism 96, 100, 103, 165, 172 neo-Darwinian model of evolution 96 nerves 61–2 nervous system, the 61, 62, 127 new atheism 155–8 Newton, Isaac 51, 53, 58, 62, 92 noble gases 148 nomothetic research 136 novelty effects 127 nuclear power 32 objectivity 49–56 observation 56, 140–3, 165, 166, 170, 184, 200, 201, 210, 211, 212 classroom 37, 72, 108, 194 in learning 30, 63, 140–3, 166, 170, 200–1, 204, 207, 210 in science 30, 49, 50–2, 56–7, 164–6, 184, 201, 201, 211–12 observing teaching 12

Index Occam’s razor 57 Ockham’s razor. See Occam’s razor Octet conceptual framework 101 octets of electrons 100–3 On the Revolutions of the Heavenly Spheres 179 Ontology 47, 72 open access publications 15 optimum guidance in teaching 196 origins of alternative conceptions 101 Origin of Species, the 165, 167 over-loaded working memory 210 oxygen 51, 52, 89, 98 paradigm-shift 10 particle models 175–90 Pedagogic content knowledge (PCK) 75–7, 128, 198 pedagogic knowledge 73–7, 126 peer tutoring 219–21 personal constructivism/constructivist 27 personal constructs 99, 103 personification 63–4 phenomenological enquiry 27 phenomenology 27 philosophy 3, 10, 40, 48, 163 phlogiston 49, 51–4, 96, 98, 160 photosynthesis 140, 148, 177 phronesis 11, 33 Piaget, Jean 74, 78, 92–3 Piagetian stage theory 74 pickpockets as an urban myth 149 pipeline argument for teaching science 26 placebos 128 planning teaching 79, 107, 110–11, 201, 213, 219 plant(s) 46, 50, 59, 123, 148, 176, 177 ambiguity 46, 177 Plato 62 plausible mental constructions 99 play in learning 195, 205 P-O-E technique 200 positivism/positivist research 71 post-tests 104, 122, 123, 197 post-tests, deferred 122 pragmatism 204 pre-requisite knowledge 105, 192 presentation skills 39 preterhuman discarnate beings 166 pre-tests 104–6, 122, 123 Priestley, Joseph 49, 51–3, 98 prior learning/knowledge 76, 80, 83, 85, 87, 91, 106, 210, 216 professional identity 3–6 professional lexicon of teachers 46

progressive education 112 project-absed teaching 40, 41 proof in science 155 publication of teacher research 20 pupil voice. See student voice pure fruit juice 176–7 purity 47, 137–8, 175–8 purposes of teaching 195, 207 quanticles 100, 139, 180–8 quantum mechanical tunnenling 149, 181 radioactive dating 57, 170 randomisation 129–30, 197 randomised field trials 197 reality 56, 57, 84 recipe practicals 205 recording teaching 12 redshift 57 reductio ad absurdum 50 reflective approach to teaching scientific accounts 173 refutation 142–4 reinforcement of learning 169, 217 relativity/relativism 30, 50–1, 142, 160 relevance 59, 70, 111, 148, 178, 185, 192–3, 201, 211, 212 religion 55, 147–59, 173 research-based practice/teaching 10–12 research ethics 12–13, 19–20, 104, 116, 129 research literature 7, 14, 18, 59, 95 research methodology 12, 37, 47, 72, 130, 205 research programme 12, 92, 137 respiration 105, 123, 148 rhetoric 13, 29, 34, 46, 48, 212 rhetoric of conclusions-science as 34, 212 RNA 96–7 rote learning 88, 90, 113, 122, 208–9, 216 Royal Society of Chemistry 15–17 Royal Society, the 15, 16, 151 sampling in research 37, 65, 86, 130, 136–8, 194, 198–9, 208–9 purposeful 65, 208 random 129–30, 197 scaffolding 75, 106–7, 115–20, 214, 217, 220 PLANKS 106, 119 POLES 119–20 scheme of work 6, 20, 27, 41, 108, 197, 199, 207 science as a cultural activity 29, 55 as a practical activity 178, 210, 212

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Index as dialogic process 123–5, 184 as theoretical knowledge 34, 98 vocabulary 46, 47, 59 science-in-the-making 34 scientific attitude 13, 58, 137, 142, 151 scientific investigations 55, 56, 203 scientific knowledge as provisional 66, 95, 144, 145 scientific literacy 9–10 scientific value 148, 161 scientific virtue 148, 161 scientific worldview 150 scientism 56, 156–9 searching for research articles 17 self-correction in science 58 sensori-motor domain 30 setting 218 sexual dimorphism 167 sexual reproduction 167 Shereshevsky, Solomon 80, 81, 85 simile(s) 61, 65, 109, 110 simplification 59, 65–6, 90, 98, 196 optimal level of 196 simulation computer 143 mental 110 skills 65 cognitive 75, 91–3, 105, 121, 204 communication 39 developing student 33, 35, 43 enquiry 204, 201 group-work 219 language 59 manipulative 30, 164, 204, 210–11 metacognitive 109 observational 30 presentation 39 sleep 71, 84 smallpox 33 Snow, C.P. (Baron) 29, 30 social capital 38 social constructivist 27 socialisation 151 socio-scientific issues 32, 34, 40, 122, 216 Socrates 62 Socratic dialogue 91 solar system 50, 62, 137, 138, 179 space-time 51, 53 specialisation 151 specialism (within science teaching) 5, 6 special needs 213, 218 speciation. See macroevolution

species 27, 32, 33, 39, 46, 102, 115, 154, 155, 165, 166, 167, 169, 170 speed of light 50, 142 spiral curriculum 90, 105, 193, 194, 195 spiritualism 166 states of matter 177 statistics 82, 130, 196, 198 STEAM education 41–2 STEM 27–8, 41–2, 197 stereotyping of scientists 30 streaming 218 student centred learning 112 student voice 26, 36–7, 126 Studies in Science Education 14 subject knowledge 5, 6, 7, 69–78, 81, 87, 105, 114, 126, 129, 168 substances 47, 87–90, 176, 178, 185–9 substances and materials 86, 176, 177, 178, 186 summative assessment 103 Summerhill school 113 supernatural 55, 56, 155–9 survey 129, 204 symbolic representation in chemistry 186, 189–90 in culture 115–16 symbolic tools for thinking 116 symposium, the 62 talented, the 213 teaching/learning activities 108 analogies 201 as actions intended to bring about learning 72 as enquiry 203–12 cycles 76, 198 defined/conceptions of 71–3 models 59, 64, 65, 201 moves 107–10, 119, 125 to the test 74, 184 techné 11, 33 theism 156 theory, in education 73–8, 112, 123 theory, in science 53, 144, 160, 166, 184–6, 201, 210, 212 and evidence 10–11, 33, 98, 164 competing 99 ‘just a theory’ 34, 170–2 provisional nature 58, 66, 97, 114, 144, 174 status of 33–4, 160 testing 50 theory of instrumentation 142–4

Index thermal expansion 182–5, 188 thought experiments 50, 56, 105, 115–16, 125, 177 triangulation 37 triple science 28 triplet, chemist’s 186–90 two cultures 29, 30 unfamiliar, making it familiar 61, 65, 80, 91, 93 universal gravitation 51, 57, 166 useful ambiguity 188–9 values 6, 20, 30, 31, 32, 40, 41, 43, 57, 58, 62, 102, 148, 161, 204, 218 and wisdom 11, 32–3, 40 educational 6, 31, 43 personal 10, 20, 30–1, 102, 123, 204 scientific 52, 57–8, 148, 161, 218 vocabulary 46–7, 59 Vygotsky, Lev 75, 78, 115, 116, 123, 215, 218

wait time 75, 89 Wallace, Alfred Russel 29, 164, 165, 166 Watson, James 165 wisdom 33 witch doctors 151 witchcraft 151, 171 word equation 188 scientific 150 theistic 55 working memory 35, 80–2, 83, 85, 119, 168, 187, 210 worldview 54, 55, 56, 147, 150, 151, 159, 166 Young Earth creationists (YEC) 57, 153, 155–8 zone of actual development (ZAD) 215–17 zone of distal development (ZDD) 215–17 zone of proximal development (ZPD) 123, 215–17

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