Air

Citation preview

533

Adler

Ad5a C641077

Air

J533

Adler

Ad5a C641077

Air

PUBLIC LIBRARY FORT WAYNE AND ALLEN COUNTY, IND. ALLEN COUNTY EXTENSION DEPT.

STO

AIR Irving and Ruth Adler

The John Day Company — New York

The "Reason Why" Series by Irving and Ruth Adler

NUMBERS OLD AND NEW THINGS THAT SPIN

SHADOWS THE STORY OF A NAIL RIVERS

why? A Book

of Reasons

OCEANS AIR

© 1962 by Irving and Ruth Adler must not be reproduced in any form without permission. Published by The John Day Company, 62 West 45th Street, New York 36, N.Y., and simultaneously in Canada by Longmans Canada Limited, Toronto.

All rights reserved. This book, or parts thereof,

Library of Congress Catalogue Card Number: 62-10935

Manufactured

in the

United States of America

Contents The Blanket Around Us

4

What

6

Is

Air?

The Color

Why

of Air

Things Burn

8

10

Oxygen and Living Things Carbon Dioxide and Living Things Nitrogen and Living Things Seeds, Pollen and the Wind Air Has Weight Barometers and Drinking Straws

22

A

24

Blanket for the Earth

12

14 16 18

20

The Weather Factory

26

A

28

Big Circle of Air

Molecules, Atoms and Ions

30

Mirrors and Whistles

32

Neon Lights in the Sky The Stratosphere

34

Man

38

Takes

to the Air

36

Taking Care of Air

42

The Changing Atmosphere

46

Word

48

List

T/i£ Blanket

Air

is all

around

Around Us

us. It

covers the earth like

attention to the blanket of air in

We have

pay

which we

live.

We the

when we

don't

to the air in a tire

when So we

do pay attention

to air

we

need.

much

as

air as

pay attention

becomes

tire

pump more

into

flat.

we

don't

a blanket. But most of the time

The

tire

needs

air.

it.

We pay attention to the air near a fire when the

begins to go out.

fire

keep

it

burning. So

ing brings

We

fire

we blow on

needs

the

fire.

air to

Blow-

air to the fire.

pay attention

breathe

We

more

The

to the air

we need

when we have been running very

to

fast.

gasp and pant because our bodies need

more faster.

air.

The gasping helps us

get the air

Mm

M:

ft

The

diver pays attention to the air he needs

to breathe

when he

can't get air

goes under the water.

from the water the way a

does. So he takes a tank of air

down with

He fish

him.

The spaceman pays attention to the air he needs to breathe when he goes off in a rocket. There

man

is

no

air in

outer space. So the space-

takes an extra supply of air with

him

in

his rocket ship.

In this book

important to

we

us.

We

made of. We shall how it sometimes shall find out

that

happen

The

shall find out

why

shall find out

find out

air

what

how we

use

gets in our way.

is -so

air

it

is

and

And we

about some interesting things

in the earth's blanket of air.

earth's blanket of air

phere (AT-muss-feer).

is

called

its

atmos-

Put the upside-down glass into the pot of water

What There

poem

a counting

is

Nineteen, twenty,

But the there

First glass

glass really isn't

is still fill

Is Air?

my

glass

empty.

is

It is

way:

empty.

easy to show that

something in the glass after the milk

a large pot with water.

and turn

it

upside down.

glass into the pot of water. glass

that ends this

because there

is

Then

is

gone.

take an "empty"

Now put the upside-down The water

doesn't

fill

the

something in the glass that keeps

the water out.

Now

tip the glass

jump out do

this.

over in the water. Noisy bubbles

of the glass to the top of the water

The bubbles

are bubbles of

Air was in the glass

air.

when you put 6

when you

the glass into the

Tip the glass over in the water

pot of water.

You could not

there just the same. Air

your room.

It filled

a gas.

space as

it

can reach.

is

many

air

was

It

could do fill

this be-

as

much

gases that are mixed together. Air

mostly nitrogen (NY-tro-jen) and oxygen (OX-i-jen).

There is

really

But the

A gas always spreads out to

is

is

air.

every crack and corner of

the glass, too.

cause air

Air

fills

see the

is

four times as

much

nitrogen in the air as there

oxygen. Air has some carbon dioxide (CAR-bun di-OX-

ide) in

it,

When

too.

The name of this gas is steam or water vapor. There is a small amount of water vapor in air. Air has a little bit of helium (HEEle-um) and hydrogen (HY-dro-jen) in it, too. Helium and water boils

hydrogen are very

it

becomes a

light gases.

7

gas.

The Color

You cannot air in

of Air

see the air in a glass.

You cannot

your room. You cannot even see the

your house. Most of the time you cannot see

you are looking through a

You can

see air

little bit

when you

of

air air

see the

around because

it.

look through a lot of

When you look at the sky above you on a sunny day, are looking through miles looks blue. Blue

is

and miles

the color of

air.

of

air.

Here

Then is

it.

you

the sky

the reason

why.

The air looks blue when sunlight passes through it. The light of the sun is white. But white light is really

many

colors

mixed together. Blue

is

one of the colors

sunlight.

White

light is really

many

colors

mixed together

in

^

Prebits of gas and dust

any other

light of

color.

in

the

So blue

air scatter

light

blue light

comes

to us

moreH

from

all

par!!

of the bright sky.

The sends

air takes

it

the blue light out of the sunlight and

to our eyes. It does

of tiny bits of gases. too.

These

They

it

in this

There are tiny

bits of gas

and dust

way. Air

is

made up

bits of dust in the air,

act like

little

mirrors.

scatter the light of the sun all over the sky. This

makes the sky look bright during the daytime.

The

bits of gas

and dust do not

of all the colors in sunlight.

They

scatter equal

amounts

scatter blue light

more

than light of any other color. Blue light comes to us from all

parts of the bright sky. So blue

ing the daytime. 9

is

the color of air dur-

Why

Things Burn

Watch it burn for a Then cover the candle with a jar. Watch the flame.

Set a lighted candle in a dish. while. It gets

smaller and smaller. Soon

The candle burns

well in the open air because

taking something out of the air

oxygen out of the a

jar,

goes out.

it

air.

When

all

the time.

the candle

is

It is

taking

covered with

the candle takes oxygen out of the air in the

After a while

all

the oxygen in the jar

is

it is

jar.

used up. The

candle cannot burn without oxygen. So the flame goes out.

A

candle

is

made

of paraffin

burns. Paraffin has hydrogen

(PAR-a-fin).

and carbon

in

it.

Paraffin

As paraffin

burns, the oxygen in the air comes together with the

hydrogen and carbon. The oxygen comes together with

make water

The oxygen comes together with the carbon to make carbon dioxide. The burning also makes heat and light. The water vapor and

the hydrogen to

10

vapor.

carbon dioxide become part of the

When wood burns,

the

fire also

air.

makes carbon dioxide

and water vapor.

The

air gets

some

of

its

carbon dioxide and water

when things burn in it. We can make a fire burn better by giving it more oxygen. We do this when we blow on a fire gently. The blowvapor

ing brings

more oxygen

to the fire quickly.

We can make a fire go out by taking away the oxygen it

needs to keep burning.

A

fire

extinguisher (ex-TING-

wish-er) works this way. It sprays carbon dioxide over

the

fire.

Carbon dioxide

close to the

So the

fire

fire. It

keeps

is

heavier than

air

goes out because

air.

So

it

stays

from coming near the it

fire.

has no oxygen to keep

it

burning.

Carbon dioxide stays close to the fire, so the fire goes out.

the

fire.

It

keeps

air

away from

Bone

Blood cells

Eye cells

Skin cells

cell

Oxygen and Living Things There this fire

is

a

that burns inside

fire

has no flame.

The

you

all

fuel for this fire

the time. Only is

the food you

You get the oxygen for the fire when you breathe. The tiniest part of your body is a cell (SELL). There

eat.

and skin

are hair cells cells.

There are

There cell

is

a

cells.

cells in

fire

There are bone

cells

and eye

your blood.

that burns inside every

cell.

So every

must have food and oxygen. You eat food. Then your

blood carries the food you eat to every

cell in

You breathe

cells

air into

gen from the

air in

your lungs. Blood

your body.

take the oxy-

your lungs. Then your blood carries

the oxygen to every cell in your body.

The burning inside your cells is like the burning of the candle. The food you eat has carbon and hydrogen in it.

When the food burns inside your cells, oxygen come together

the hydrogen and

make water vapor. The carbon and oxygen come together to make carbon dioxide. The to

burning also makes heat and energy.

The heat made by the burning keeps your body warm. The energy made by the burning makes you able to do things. It

and

makes you able

to

to play. 12

walk and

to run, to

jump

Your blood

carries

away

the water vapor and carbon

dioxide

made by

them

your lungs. The water vapor and carbon dioxide

to

leave your

the burning inside your

body when you breathe

You can show

that

cells. It carries

out.

you breathe out water vapor.

Breathe out through your mouth against a window.

There

a cloud on the

is

touched

it.

The cloud

is

window where your breath made of tiny drops of water.

The water vapor in your breath changed to tiny drops of water when it touched the window. Other animals need oxygen, too. They use it in the same way that you do. Plants also need oxygen for burning their food.

1.

You breathe

They get their oxygen through their leaves.

You breathe out carbon dioxide and water vapor

air

into your lungs

Blood takes water vapor and carbon dioxide from your eel Is

Blood cells take the oxygen from the air in

to your lungs

your lungs 4.

...to every cell in

3.

Blood takes the oxygen

your body

Carbon dioxide

0m& Carbon Dioxide and Living Things All living things to

make heat and

need food. They need food

energy.

They need food

to

as a fuel

make them

grow.

own

They make their food in their leaves. The food they make is sugar. Sugar is the food they need to make them grow. Green plants make

Carbon is one

their

food.

of the things out of

which sugar

Green plants get carbon from carbon dioxide

Water

made.

in the air.

another thing out of which sugar

is

is

is

made.

Green plants get water from the ground through

their

roots.

When make

carbon dioxide and water come together to

sugar, energy

is

used up. Green plants get the

energy for making sugar from sunlight.

When

green plants use the energy of sunlight to help

them make

their food,

it is

called photosynthesis (foto-

SIN-the-sis).

Carbon dioxide has carbon and oxygen

away from

the

it.

When

make sugar, they take oxygen. Then the oxygen is

green plants use carbon dioxide to the carbon

in

14

left over.

The oxygen goes back

always oxygen in the

and

for

into the

air.

So there

is

animals and plants to use

air for

burning to take place.

There

is

always carbon dioxide in the

air, too,

Some

plants to use for photosynthesis.

of

it

for green

gets there

Some of it gets there from volcanoes. Some of it gets there when things like coal and wood burn. And some of it gets there when

when plants and

animals burn their food.

dead things decay. Animals cannot make their like rabbits,

cows and

own

food.

Some

horses, get their food

green plants. Other animals, like lions and their food

by eating the animals

animals,

by eating tigers, get

that eat green plants.

People get their food by eating plants and animals. So all

animals need green plants to

make

their food for

them. Carbon dioxide

There

is

always carbon dioxide

in

15

the

air for

green plants to use

Nitrogen and Living Things All living things build nitrogen into their bodies. is

nitrogen in the air

There

around them. But most living

all

things cannot use the nitrogen in the

air.

Animals get their nitrogen from the plants or animals they

eat.

Most plants get

their nitrogen

from the

soil in

which they grow.

When

nitrogen comes together with hydrogen, am-

monia (a-MOAN-ya)

is

made. There

which plants grow. Plants get

soil in

gen from the ammonia in the

When nitrogen comes

ammonia in the some of their nitrois

soil.

together with oxygen and some

other chemicals, nitrates (NY-trates) are made. There are nitrates in the soil in

some

of their nitrogen

which plants grow. Plants get

from the

nitrates in the soil.

So plants are always taking nitrogen out of the

Some the air

of the nitrogen in the soil

all

the time. There are tiny

is

being put back into

little

called bacteria (back-TEER-ee-a).

plants in the soil

Some

bacteria take

away from the oxygen and other chemicals They put the nitrogen back into the air where

the nitrogen in nitrates.

soil.

most plants cannot use

it.

Bacteria that put nitrogen into the soil

So the nitrogen

in the soil

ways.

Some

of

being put back into the

all

it is

of

it is

being used up in two

would be no nitrogen

soil

only this happened,

air. If

would be

for plants

lost.

Then

and animals

there

to use.

lucky that there are some plants that take nitro-

gen from the

air

and put

it

back into the

are called legumes (leg-YOUMS).

bumps on their roots.

soil.

The

plants

Legumes have

air.

They change

trogen so that the legumes can build

it

the ni-

into their bodies.

the legumes put nitrogen into the

soil for

plants to use. Peas, beans, peanuts

The

little

Bacteria live in these bumps. These

bacteria take nitrogen from the

Then

Some

built into the bodies of plants.

the nitrogen in the

It is

is

and clover are

all

root of a pea plant. Bacteria live in the

legumes.

bumps.

other

The

spreads these seeds

air

The air helps many plants spread their seeds. Some seeds are put in the ground by people when they plant gardens. Some seeds stick to the fur of animals. The seeds fall to the ground as the animals move. Some seeds are carried by the wind. The wind is moving air. Seeds that are carried by the wind must be very light. But the seeds are heavier than the So sooner or later they

fall to

air that carries

the ground.

Seeds that are carried by the wind

may have

like the seeds of

maple

trees.

like little balls of fur, like the seeds of the

Sometimes the wind that

makes the

seeds.

special

They may They may look

shapes that help them ride on the moving

have wings,

them.

air.

milkweed.

by moving the plant become dry after they

carries seeds

These plants

have made their seeds. The dry plants break away from their stems.

The wind

ground. As the plants to the ground.

rolls

roll

the dry plants over the

over and over, their seeds

Tumbleweeds spread

fall

their seeds in this

way. They are called tumbleweeds because the wind tumbles the dry plant over the ground. 18

The air also helps many plants make their seeds. It helps by carrying pollen (POLL-en). Pollen is a very fine powder that grows on flowers. Pollen helps to make a seed.

But

first

the pollen must be carried to the part of

the flower where the seed

Sometimes

is

made.

insects carry pollen. Insects carry the poll-

en on their bodies.

Sometimes the wind carries pollen. The wind can carry the pollen of

many

grasses

and

trees

because pollen

is

so

light.

Pollens carried fever.

Hay

by the wind give some people hay

fever makes

eyes turn red. People of trees, grasses

them sneeze and makes

may

their

get hay fever from the pollen

and ragweed.

Different kinds of pollen

19

Air

Has Weight

Air has weight. Although air

The

is

very

weighed on a

scale.

weighing very

light things like air. Air

cups of

air

weigh

Because

air

of air doesn't

The

air in a

and 10

The It is

air

piled

much

from the earth.

so light,

as

can be

is

so light that

800

one cup of water.

you may think that a roomful

weigh very much.

schoolroom that

feet high

the earth as

is

it

scientist has a special scale for

much

as

light,

is

If

you do, you are wrong.

30 feet long, 20 feet wide

weighs almost 500 pounds!

above us reaches higher than any schoolroom.

up high above the is

earth.

The

pile of air

above

thousands of miles high.

It

spreads out to

can reach. But

it

never goes away

space as

it

earth. Its

weight keeps pulling

it

back

fill

to the

Air pressure at sea level is

15 pounds per square inch

pressure

Peak

The weight

of the air

is

9 pounds per square

inch.

above the earth keeps pressing

down on everything on the earth. It keeps pressing down on you, too. More than 12 tons of air are pressing down on you right now. This is like having two large elephants pressing down on down on the earth.

It

keeps pressing

you!

Why reason

you crushed by

aren't is

this great

that air isn't only around you.

The

side you, too.

air inside

weight? The

There

is

air in-

you pushes back. This push

back keeps you from being crushed.

How hard of anything

the air presses

is

known

Air pressure It is

isn't

down on

as air pressure

pressing

is

because there

down near

The bigger pile

(PRESH-er).

the same everywhere on the earth.

greater near the ocean than

mountain. This

every square inch

it is

is

on the top of a

a bigger pile of air

the ocean than on a mountain top.

of air has

more weight and

harder. Air pressure at sea level

square inch. 21

is

presses

down

about 15 pounds per

pushes the mercury up the closed tube

2. This

1,

Air presses

down on the

mercury

the dish

in

A mercury barometer

Barometers and Drinking Straws

We eh-ter)

measure .

air

pressure with a barometer (bar-OM-

A barometer has a glass tube that is closed at one 22

The tube has mercury (MER-cure-ee) in it. The tube held upside down. The open end of the tube is in a

end. is

little

dish of mercury. There

of the tube

the tube.

nothing in the closed end

is

above the mercury. There

The

The weight

ruler

is

marked

is

a ruler next to

off in inches.

above the dish presses down on

of the air

The pressure on the mercury in the dish pushes the mercury up the tube. To measure the pressure, we read the number of inches that the mercury has climbed up the tube. At sea level, the mercury in the the mercury in the dish.

tube reaches 30 inches. So level

is

we

say, "Air pressure at sea

30 inches."

Mercury

is

used in a barometer because mercury

very heavy. Water

is

much

lighter than mercury. Air

up an empty

pressure at sea level pushes water 30 feet tube. So a water barometer

is

would have

to

be 30

feet

high!

Air pressure helps you drink water from a drinking straw.

You put one end

You put

When air

of the straw into a glass of water.

the other end of the straw into your mouth.

you drink from a drinking straw, you suck the

out of the straw.

barometer.

Then

The weight

the straw

of the air

is

like the

above the

tube of a

glass presses

down on the water in the glass. The pressure on the water pushes the water up the straw into your mouth. 23

A You wear getting out. side

Blanket for the Earth

a coat to keep the heat of your

You wear

from getting

in.

body from

a coat to keep the cold winds out-

So your coat keeps you

warm even

on very cold days.

The wears.

atmosphere

earth's

The

is

like a coat that the earth

thick blanket keeps the earth from getting

too cold at night and in the winter.

It

keeps the earth

from getting too hot during the daytime and mer.

It

in the

sum-

keeps the temperature of the earth just right for

living things.

The sun sends

we get warm from

us light rays and heat rays. So

the light to see with and the heat to keep us

The sun sends us other rays, too. It is lucky for some of these rays never get through the earth's

the sun. us that

blanket of

air.

There are X-rays

in sunlight.

Doctors sometimes use

X-rays to take pictures of the inside of your body.

They

do not use X-rays often because X-rays can hurt

living

The X-rays in sunlight never reach the earth. They are stopped by the earth's blanket of air. There are rays in sunlight that make you get sunburned on a bright summer day. They are called ultrathings.

violet rays. If all these rays got

would

kill

you. Only a small

through to the earth they

amount

of these rays

do get

through. Most of these rays are stopped by the air high

up above the

earth.

24

X-rays and ultra-violet rays

The earth's atmosphere burns up most meteors

are stopped by the earth's

atmosphere

at

earth's •tfxfc

mo sph e re

There are pieces of metal and rock that travel around

They

in space.

meteors

fly

most meteors burn up right away.

moving

teors, the earth's

A

As they rub

into the earth's atmosphere.

They

against the air they get very hot.

little lights

Many

are called meteors (MEE-te-ors).

across the sky.

get so hot that

We see them as bright By burning up

the me-

blanket keeps them from falling on us.

blanket can also get in your way.

from finding out what

is

It

can keep you

on the other side of the blanket.

We find out about the sun and the stars by the light that comes from them. The of the sunlight

hides

some

That

is

(

and

earth's blanket of air stops

starlight

of the facts that

one reason

why

S AT-el-lites ) into space.

of the sun

blanket of

and the

stars

from getting

we might

to us.

some So

it

get from this light.

scientists are putting satellites

The

satellites

can take pictures

from the other side of the

air.

25

earth's

The Weather Factory

The

earth's blanket of air

But most of the above the

air in

earth. This

is

thousands of miles thick.

the blanket

is

less

than 10 miles

lower part of the atmosphere

is

called the troposphere (TROP-a-sfeer).

Plants

and animals can

live

only near the bottom of

They must live near the surface of the earth where there is enough oxygen for them. They cannot live more than 3M miles above sea level without help.

the troposphere.

Mountain climbers know

them

to breathe

when they

The temperature in

this.

So they take oxygen with

are high up.

of the air in the troposphere

changes

an interesting way. The higher you go into the tropo-

sphere, the colder

it

gets.

Then you reach

a place where

Radio Corporation of America

26

it

stops getting colder as

where the temperature

you go higher. You reach a place stays the

time and nighttime. This place

same during the daywhere the troposphere

is

ends.

The troposphere earth. It

is

called the weather factory of the

is

in the troposphere that all the things

weather happen. Here place to

is

where

make winds. Here

water vapor in the

air.

is

find

Here

is

where you

find rain

to

most of the

where clouds form when

water vapor changes back to drops of water or ice.

call

moves from place

where you

is

Here

air

we

and snow. Here

is

bits of

where

storms are made.

Weather

stations

and pressure

ture

on the ground measure the tempera-

of the air near the ground.

ure the speed of the wind. the

They

They meas-

find out the direction

wind comes from.

Balloons with radios carry the tools of the weather-

man

high up into the troposphere. The radios send back

messages to the weather stations on the ground. In

way

the

weatherman

finds out

pressure and winds are high

Weather

down on

up

this

what the temperature, in the troposphere.

450 miles above the earth look

satellites

the troposphere from above.

They send back

pictures of the clouds.

Using

all

these facts, the

the weather

is

weatherman

He and why

going to be.

the weather changes

27

figures out

also tries to find out

storms take place.

what

why

The

big circle of air in a

A

Big Circle of Air

room

Electric heaters are sometimes used to

warm. Here

is

how

make rooms

they work.

The hot wires of the heater heat the air around them. But when air is made hot it gets lighter than the rest of the air near it. So the lighter, warmer air around the heater wires begins to rise. When the warmer air rises, it leaves a space. Cool air moves in to fill this space. But then there is a space where the cool air had been. So air from above moves in to fill this new space. In this way the air in the room begins to move in a big circle. When air

moves

in a circle like this

(SIR-kyou-lates).

near the heater

is

When

we

say that

it

the air circulates, the

carried to

all

28

circulates

warm

parts of the room.

air

The

air in the

circulate

troposphere circulates, too.

begins to

when air near the ground is warmed by the

This makes the air place of this

warm

rise. air.

Cool

air

moves

The moving

makes surface winds. While the air in the troposphere cles,

It

the earth

is

spinning

all

air

is

in to take the

near the ground

moving

the time.

sun.

in big cir-

The spinning

of

the earth turns the surface winds.

The

picture shows the big circles of air in the tropo-

sphere and the paths the surface winds follow.

0=0

29

.

Atoms and Ions

Molecules,

The a-kule)

smallest piece of anything .

a molecule

(

MOLL-

Molecules are so small that they cannot be seen.

Molecules are moving

all

the time. Air has molecules of

nitrogen, oxygen, water vapor

Molecules are

Each molecule two atoms

of

made up

and other gases

in

it.

made up of bits called atoms AT-ums (

of

oxygen

in the troposphere has

)

two

Each molecule of water vapor has hydrogen and one atom of oxygen. Atoms

atoms of oxygen in

are

is

it.

of pieces of electricity.

They are called positive and negative electricity. Each atom has positive and negative electricity in it. The smallest piece of positive electricity is a proton (PRO-ton). The smallest piece There are two kinds of

of negative electricity of the time

of positive

is

electricity.

an electron (ee-LEK-tron). Most

an atom or a molecule has the same amount

and negative

electricity.

Sometimes an atom or a molecule trons.

The

lost electrons float

A hydrogen atom

around

in the air loses elec-

in the air.

Then

An oxygen atom 30

the

atom or molecule has more positive

atom or molecule has a

electricity.

positive charge.

Sometimes an

atom or molecule picks up electrons that are around

Then

in the air.

So the

floating

the atom or molecule has

more

negative electricity. So the atom or molecule has a negative charge.

When

charge,

called an ion (EYE-on).

it is

an atom or molecule has a positive

molecule has a negative charge,

The

electrons that float

ions because they

around

it is

When

an atom or

called an ion, too.

in the air are also called

have charges.

Rays from outer space, X-rays and other rays from the sun stream into the earth's atmosphere. They change the molecules of

phere into

air in

So

ions.

upper layer

is

the upper part of the earth's atmosthis

upper layer

is

full of ions.

This

called the ionosphere (eye-ON-a-sfeer).

The ionosphere begins 50

miles above the earth.

to the top of the earth's blanket. It goes to

It

goes

where outer

space begins.

A water molecule.

It

has two atoms of hydrogen and one atom

of oxygen.

31

Mirrors and Whistles In 1901 a message was sent across the Atlantic Ocean. This message was not carried by wires.

It

was carried by

radio waves. Scientists

were surprised that a radio message could

travel so far.

Radio waves travel through the

straight lines.

But the earth

is

air in

round. So the scientists

thought that the radio waves wouldn't travel around the

They thought the waves would go off into space or bump into the ground. The first picture shows you what they thought would happen. earth.

When

the message did cross the ocean, the scientists

tried to find the reason

the ionosphere.

why. This

They found

sphere acted like

little

go

They were

off into space.

how

they discovered

that the ions in the iono-

mirrors.

Scientists thought a radio at

from A

is

The

radio waves did not

sent back to the ground

B couldn't receive

a

by

message

the ions in the ionosphere.

how

The second

picture shows you

the ionosphere helps radio waves travel long dis-

tances around the earth.

There are many other interesting things that happen in the ionosphere.

The ionosphere helps make whistlers (WHISS-lers). You can hear whistlers on the radio during thunderstorms. First you hear a click. This is when there is a flash of lightning. Then you hear a long, low whistle. This

is

the whistler.

Flashes of lightning send out radio waves.

waves

travel

up

Some

of the

They travel to where waves make the whistle

to the ionosphere.

the ionosphere ends. These radio

you hear on your

radio.

Whistlers have helped scientists figure out that the

ionosphere goes up 7,000 miles above the earth.

2

0^ ASPH

^

Streams

of electrons

Sun

Neon

On of

Lights in the Sky

clear nights the sky

many colors.

is

often

made

bright

by

lights

In the north, the lights can be seen in the

northern sky. Scientists

call these lights

aurora horealis

(or-OR-a bore-ee-A-lis). Aurora borealis means northern lights.

When we see aurora lights in the sky, earth's

atmosphere

lights are

come

made by

to the earth

of electricity

is

it is

because the

acting like a big neon light. Aurora

streams of electrons and protons that

from the sun.

come

When

these

into the ionosphere,

little

pieces

something hap-

The protons come together with electrons in the ionosphere to make hydrogen atoms. When they do this,

pens.

light like

is

given

off.

wide bands of

Aurora

lights

made

in this

way

look

light.

Later on, the aurora lights look as though they came 34

^ and protons

^^

—

___^

Aurora lights are seen here

from great colored trons

This happens

bump

atoms in the ionosphere.

from the sun

When

the atoms are

colored light

made

hit,

lights.

Only these

do not see these

into

they give

in this

off light.

The

elec-

rays of

way move back and

forth

C6 41.077'

across the sky.

There are other

when

flashlights.

lights in the sky that are like aurora lights are in the sky all the time. lights

You

during the daytime. Daylight

hides them. At night they are hidden

by

starlight

moonlight. Scientists call these lights airglow.

though they cannot see airglow,

scientists

and

Even

can study

it

They know that oxygen atoms in the ionosphere make the red and green lights of airglow. They know that sodium (SO-dee-um) atoms in the ionosphere make the yellow light of airglow. Oxygen and sodium atoms make the colored lights when they are hit by ions that come from outer space.

with special

tools.

35

The Stratosphere

The

stratosphere (STRAT-a-sfeer)

about 40 miles thick.

It is

is

a layer of air

between the troposphere and

the ionosphere.

The bottom sphere. This

is

of the stratosphere touches the tropo-

where you

find the jet streams.

streams are very fast winds.

They

travel

The

jet

250 or 300 miles

an hour.

Weathermen have made maps found that the

jet

waves. The waves

of the jet streams.

They

streams follow paths that look like

move from west

to east.

The waves

carry large pieces of air from the troposphere with them.

These pieces jet

streams,

of air

make our weather. By studying

weathermen can

tell

what the weather

is

the go-

ing to be for the next few weeks.

The weather is best when there are some days that are sunny and some days when it rains. Too much sun makes plants dry up and die. Too much rain brings floods. Weathermen can tell when there will be days and days of rain. They can tell when there will be days and days of dry weather, too. They can tell by looking at the maps of the jet streams. The weather will be bad when the jet waves do not move for weeks and weeks. The stratosphere is a quiet layer of air. It is above the storms and winds of the troposphere. aurora

lights,

It is

below the

airglow and whistlers of the ionosphere. 36

The temperature

of the air in the stratosphere never

changes very much. So the stratosphere for looking

around

at the earth's

is

a good place

atmosphere and outer

space.

Very large sphere.

They

plastic balloons float

up

into the strato-

carry telescopes, cameras and other tools

of the scientist. Because the stratosphere

is

so quiet, the

balloons can stay in one place for a long time. eras

and telescopes take

The cam-

fine pictures of clouds

and

of

the sun. Other tools study the gases that are found in the stratosphere.

37

General Mills

^_c Man

Takes to the Air

Man saw insects and birds flying in the air. He saw seeds carried by the wind. Out of the things he saw, man built his dreams. He built dreams of First

flying.

he tried to

wings to

He tied great

body. But his body was not light

his

The bones

like a bird's. air

a bird.

fly like

of a bird

spaces in them. So a bird's

strong wings can

bones have few

lift

have many

body

into the

it

air spaces.

So

his

is

light. Its

air.

Man's

bones are

The wings man made were not strong enough to lift his heavy body into the air. Then man wanted to have the wind carry him like a seed. He drew pictures of his plans. Some of his pictures looked like parachutes.

heavy.

Other pictures looked

like helicopters.

was a long time ago. He never from

first flight

was made

balloon was very light. small

fire

Smoke from

fGBM

models

his plans at that time.

The

A

built

This

It

in a balloon.

was made

The

of linen.

was made under the balloon.

the

fire

went

into the balloon.

The

balloon was

with the hot smoke. The

filled

linen balloon filled with hot

than the

air.

into the

air. It

duck

its

in

gen. is

lifted

The balloon climbed 300 feet carried a sheep, a rooster and a

basket.

A little later a balloon carried a man first

lighter

around it. So the balloon was

air

up by the o^

smoke was

was

time. This balloon

Hydrogen

is

filled

lighter than

the lightest gas there

is.

for the

with hydro-

air.

Hydrogen

But hydrogen

is

not

safe to use. It burns easily.

Balloons are

still

used today. The balloons

which study the stratosphere are made tic.

The

plastic

is

hydrogen. But helium not burn.

A man has

into the air

by

light.

These balloons

Helium

isn't as light as

very

are filled with helium.

of plas-

is

safe because

it

does

been carried 20 miles up

a plastic balloon.

He made

a

parachute jump from the balloon. Balloons are useful for going high up into

9

\

They are not good for traveling long distances. They cannot travel fast because they are carried by the wind. the atmosphere.

Because balloons could not travel

fast,

one

man thought he would put an engine on a balloon. He built a balloon in the shape of a cigar. The engine made the balloon move fast. A balloon with an engine (DEER-ij-ibble).

A

ple.

is

called a dirigible

A dirigible carried many peo-

dirigible could travel faster than

Once a dirigible crossed Ocean in less than two days. But ship.

was

filled

was about

with hydrogen.

this dirigible fire as it

Many people died. Dirigibeen used much since then.

to land.

bles haven't

Airplanes are heavier than travel through the air.

into the air

V

the Atlantic

caught

It

any

when

air

An

air.

But they can

airplane

is

moves against

lifted

its

up

wings.

Some airplanes have propellers (pro-PELLers). The propeller moves the air against the airplane wings.

Some airplanes have jet engines. are very strong. So a jet plane

over the ground before over the ground,

moving

up

air lifts

air

the

Then

takes

moves very off.

moves past jet

in the troposphere.

clouds.

it

Jet engines

its

As

it

fast

moves

wings.

The

plane. Jets travel high

They

travel

above the

there are no storms to get in

way. So they can travel very

their

cross the Atlantic liners carry Still

many

Ocean

fast. Jets

in seven hours. Jet

passengers.

other airplanes have rocket engines.

rocket plane

small. It carries only

is

A

one per-

The person is the pilot. The fastest rocket plane traveled more than 4,000 miles an hour. son.

Another rocket plane flew 40 miles above the earth. It flew in the stratosphere.

Because

it

was so

little bit

of

small,

it

rocket fuel. So

could carry only a

it

Now man has

flew less than

two minutes.

taken

the ionosphere.

off into

Spaceships have carried him almost 200 miles

above the earth. Rockets carried ships up.

The

his space-

rockets traveled 18,000 miles an

hour.

The

first

spaceman traveled once around

the earth in his spaceship.

two hours

to

do

this.

It

took him

Another spaceman

veled for a day in his spaceship. trips

around the

Someday to the

than tra-

He made

17

earth.

a spaceship will take a

moon. Someday,

other planets.

less

too,

spaceman

spacemen

will visit

Los Angeles on a clear day

Division of Air Pollution

Department of Health, Education and Welfare

Taking Care of Air

We do not always take care of the air we breathe. We do not always keep air clean. We do not always keep

it

safe to breathe.

When we make air

we

breathe.

smog,

Smog

is

we

are not taking care of the

a kind of

smoky

fog.

smog in the country on hot summer days. This smog is made by gases that are given off by plants. This smog cannot hurt us. But there is another kind of smog There

is

that can hurt us.

The smog

that can hurt us

makes people cough.

It

is

usually over

bothers their eyes. 42

cities. It

It

makes

and keeps them from growing. Smog some-

plants sick

times

kills

people.

A London smog

in

1952 killed 4,000

people.

Smogs

are

formed over

cities that

have a

lot of auto-

mobiles and factories. The gases that come from the auto-

mobile

tail

pipes and the factory chimneys

make

the

smogs.

Smogs are worst over some These

cities

cities that are

near the sea.

have mountains around them. Los Angeles,

San Francisco and Rio de Janeiro

all

have bad smogs.

Harmful smogs can be stopped if people use other fuels in their

homes and factories. They can be stopped

if

they

build their cars in a different way.

Division of Air Pollution

Department

of Health, Education

and Welfare

We don't take care of the air we breathe when we test atom bombs.

When we test atom bombs we put harmful

chemicals into the

air.

can hurt us and even strontium

bomb

it

The light bits

become

Heavy

sick

and may

washed out

ing bones.

It is

is

by

rain

and

where plants can get

soil this

harmful because

(CAL-see-um). Calcium

die.

of the air

soil

them. Strontium 90 gets into the is

sprin-

around the earth for a long

snow. They are carried into the

Strontium 90

bits of the dust fall

and animals that are

of dust travel

time. Finally they are

is

carry the harmful chemicals

to the ground. Plants

kled by the dust

of these chemicals

dust with harmful chemicals

air.

They

right away.

give off rays that

90.

test,

goes high up into the

down down

One

kill us.

(STRON-chum)

After an atom in

The chemicals

it

way.

acts like calcium

used by our bodies for build-

needed especially by

little

children.

Children get calcium from the milk they drink. Milk

comes from cows. Cows get calcium from the plants they eat. Plants get

calcium from the

But strontium 90 tium 90 in the

soil,

soil.

acts like calcium. If there

plants build

it

is

stron-

into their bodies to-

Then cows build strontium 90 into milk together with calcium. Then little children

gether with calcium. their

build strontium 90 into their bones together with cal-

44

cium.

The strontium 90 can hurt

their bodies just as

X-rays can.

Children can be strontium 90.

made

safe

from the harmful rays of

They can be made

safe

if

we

atom bombs. When we test atom bombs we putstmnj^

^

The strontium 90 is washed out of the air by rain and snow. It is

carried into the soi

where plants can get

Cows

eat the plants and build

strontium

90

into theirii*fWr*

Children drink the

milk and build

trontium

90

their bones.

hurt them.

45

into It

can

stop testing

The Changing Atmosphere

The

earth was

think that

its

young

billions of years ago. Scientists

atmosphere was not the same then

as

it is

now. They think that the atmosphere has been changing the time.

all

The ter

earth was very hot

when it was young.

It

was hot-

than the hottest part of the ionosphere. Nothing could

live

on the hot

earth.

was made up mostly

The atmosphere

of the

of hydrogen, helium

young earth

and ammonia.

Hydrogen and helium are very light gases. Their weight was not strong enough to make them stay near the earth. So they got

lost to

outer space. That

is

hydrogen and helium

in the earth's

Even the ammonia got

lost.

As the earth began

The

to cool,

inside of the earth

gases.

The hot

gases

was

its

still

why

there

is little

atmosphere now.

outside began to harden.

very hot.

came out through

It

gave

off

hot

holes in the hard

:

The atmosphere of the young earth was made up mostly of hydrogen, helium and ammonia.

Hot gases from inside the earth became the new atmosphere. It had mostly carbon dioxide, water vapor and nitrogen

in

it.

These holes were

crust.

The

like the

openings of volcanoes.

gases were like the gases that

now. The gases became the

earth's

come out

new

of volcanoes

atmosphere. The

new atmosphere was mostly carbon dioxide, water vapor and nitrogen. As the earth got

and

fell as rain.

cooler, the

Rain

ried carbon dioxide

filled

water vapor cooled,

the oceans with water.

from the

air

with

it.

The

too,

It car-

rains took

most of the water vapor and carbon dioxide out of the air.

What was

Out

left in

the air was mostly nitrogen.

of the carbon dioxide, water,

in the sea

came the

living things

first

and other chemicals

living things.

were tiny green

plants.

Some of the first They could make

own food. They made their own food by photosynthesis. The oxygen made by photosynthesis went into the atmosphere. In this way the atmosphere became mostly oxygen and nitrogen. That is the way the atmosphere is their

now.

.^ Klfc

m Rain

fell. It

took most of the carbon

dioxide and water vapor out of the air.

So the atmosphere was mostly

nitrogen.

Then green plants grew. They put oxygen into the atmosphere. So the atmosphere became mostly nitrogen and oxygen.

WORD Air Pressure (PRESH-er)

LIST

— How

hard the

air presses

down on

every square inch of something.

— The earth's blanket of air. Bacteria (back-TEER-ee-a) — Tiny little plants. They are so small

Atmosphere (AT-muss-f eer)

you need a microscope

to see them.

— A tool for measuring air pressure.

Barometer ( bar-OM-eh-ter )

— The tiniest part of a plant or animal. Circulate (SIR-kyou-late) — To move in a big circle. Ionosphere (eye-ON-a-sf eer) — The upper layer of Cell

(SELL)

atmosphere. in

It

goes up about 7,000 miles and has

the earth's

many

ions

it.

Legumes (leg-YOUMS) the air and put

— Plants which help

take nitrogen from

into the soil for other plants to use. Peas,

it

beans, peanuts and clover are legumes.

—A

Meteor (MEE-te-or) around

in space.

piece of metal or rock that travels

Sometimes

it

flies

into the earth's atmos-

phere.

Photosynthesis (foto-SIN-the-sis)

— When

energy of sunlight to make their Pollen (POLL-en) It

—A

helps the flower

own

green plants use the

food.

very fine powder that grows on flowers.

make

seeds.

Stratosphere (STRAT-a-sfeer)

— The middle

layer of the earth's

atmosphere.

Troposphere (TROP-a-sf eer)

— The

bottom layer

of the earth's

atmosphere. All weather takes place in the troposphere.

48