3 13 so much energy (physical science)

Genre

Nonfiction

Comprehension Skill

Main Idea and
Supporting Details

Text Features

• Captions
• Labels
• Glossary

Science Content

Energy

Scott Foresman Science 3.13

ISBN 0-328-13845-2

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Vocabulary
absorb
electric charges
electric circuits
electric current

kinetic energy
potential energy
reflect
refract
thermal energy

Picture Credits
Every effort has been made to secure permission and provide appropriate credit for photographic material.
The publisher deeply regrets any omission and pledges to correct errors called to its attention in subsequent editions.
Photo locators denoted as follows: Top (T), Center (C), Bottom (B), Left (L), Right (R), Background (Bkgd).
6 Getty Images; 8 Getty Images; 9 Kindra Clineff/Index Stock Imagery; 10 VCL/Spencer Rowell/Getty Images; 14 Getty
Images; 16 David Wrobel/Visuals Unlimited; 21 Digital Vision.
Scott Foresman/Dorling Kindersley would also like to thank: 1, 13 Marconi Instruments Limited/DK Images; 19, 22 (R)
Stephen Oliver/DK Images.
Unless otherwise acknowledged, all photographs are the copyright © of Dorling Kindersley, a division of Pearson.

ISBN: 0-328-13845-2
Copyright © Pearson Education, Inc. All Rights Reserved. Printed in the United States of America.
This publication is protected by Copyright, and permission should be obtained from the publisher prior to any
prohibited reproduction, storage in a retrieval system, or transmission in any form by any means, electronic,
mechanical, photocopying, recording, or likewise. For information regarding permission(s), write to
Permissions Department, Scott Foresman, 1900 East Lake Avenue, Glenview, Illinois 60025.
3 4 5 6 7 8 9 10 V010 13 12 11 10 09 08 07 06 05

What did you learn?
1. Why does light refract?
2. Where do you get potential energy?
3. What are two examples of
the Sun’s energy?
4.

In this book
by Margo
Tong

you have read about waves and
energy. Write to explain how you
can tell if a wave has a lot of
energy or a little energy. Use
the words trough and crest in
your answer.
5.

Main Idea and Supporting
Details Electrical charges can be
positive or negative. What details
from the book help you understand
how charges move?


Energy
Suppose you and your family are going to
spend a day at the beach. All of you get up early,
put on your swimsuits, and eat breakfast. You
pack some towels, beach chairs, an umbrella, and
beach toys. Everyone puts on hats and sunglasses.
You put all the things you need into the car, and
you’re off!
Your parents park the car at a beach parking
lot. You walk to the beach, where you find the

perfect place on the warm sand. There you
spread out the towels, set up the chairs, and open
the umbrella. You take out your toys and start
digging in the sand. You are ready
to have fun.

You use a lot of energy to get to the beach.
Energy is the ability to do work or cause change.
Nothing happens without energy. Much of what
we know about the universe comes from the
study of energy. There are many forms of energy
and many ways to transmit energy. There are
many ways to change energy, and many ways to
store energy.
The Sun is the main source of energy for
Earth. Keep reading to find out how its energy
powers and shapes life on Earth!

The Sun is Earth’s
main source of energy.

2

3


The Sun’s energy has different forms. One
form is heat. Heat energy is created by reactions
inside the Sun. Heat travels to the Sun’s surface
and then to Earth. It causes ice to melt and water

to evaporate. The uneven heating of Earth’s land
and air causes wind, rain, and other forms of
weather.
Light is another form of energy from
the Sun. Like heat energy, it is created
inside the Sun and then travels to
Earth. Light energy helps plants
grow. There would be no life on
Earth without heat energy and
light energy.

4

There are other kinds of energy. You probably
used some energy this morning. Did you turn on
a light when you got up? If you did, the light used
electrical energy. The food you ate for breakfast
has chemical energy. If you listened to the radio,
you used sound energy. Your family used the
mechanical energy of the car to get to the beach.
Many of the energies listed are combined with
other energies. For example, a light wastes some
energy. That wasted energy is heat energy. To turn
on the radio and use its sound energy, you need
to use electrical energy. And the chemical energy
created by the gas in a car gives it the mechanical
energy needed to drive.

Eating breakfast
gives us energy.

5


What is stored energy?
Do you like to swim when you are at the
beach? If you do, you will need to use energy
stored in your body. Stored energy is potential
energy. It is inside both people and things,
waiting to be released. Whenever an object is at
rest, it has potential energy. The object uses its
potential energy when it starts moving.
An example of an object with potential energy
is a rollercoaster sitting at the top of a hill. The
rollercoaster uses its potential energy as soon as
it starts moving downhill.

6

Potential energy changes to a form of energy
to do work or to cause change. For example, the
stored energy in your body is chemical energy. It
comes from the energy in food. Airplanes also
use chemical energy. It is released when jet fuel is
burned.
Work has to be done to change potential
energy. In the case of the rollercoaster, gravity
works to make it roll downhill. In the case of the
food you eat, your body works on it to change it
to chemical energy.

7


What is energy of motion?
Are you ready for that swim? The minute you
start to swim you have kinetic energy, the energy
of motion. Everything that moves has kinetic
energy. Buses, spinning tops, running animals, and
other moving things all have kinetic energy.
Friction goes against kinetic energy, changing it
to heat. Without a new source of kinetic energy,
all objects in motion eventually come to a stop.
Playing and swimming are
forms of kinetic energy.

8

Fast-moving water has a lot of kinetic energy.
Many years ago, people figured out a way to
use that energy. They built dams to speed up
the flow of river water. The water was used
to power waterwheels. The waterwheels were
part of factories built along riverbanks. The
kinetic energy of the water turned the wheels.
The wheels were attached to factory equipment
inside. The equipment worked because it used
kinetic energy created by the moving water.
More recently, people figured out how to
make electricity from moving water. They built

dams that create electricity. These dams change
water’s kinetic energy to electrical energy.

9


Changing Forms
of Energy
Energy can change from one form to another.
This morning you ate some cereal. The chemical
energy from the cereal was stored as potential
energy in your body. That potential energy was
changed to kinetic energy when you took a swim.
You can get more potential energy by eating lunch.
Whenever energy changes form, some of the
energy is given off as heat. Your body got warmer
when it changed the cereal’s chemical energy
to kinetic energy.
During your swim,
some of that kinetic
energy heated the
surrounding water.

Your day at the beach
is over. You have gone
home. You have had
dinner and are ready to
watch television. You
take the stored chemical
energy from dinner

and turn it into kinetic
energy when you press
the remote control.
The remote control
uses several forms of
energy. Its batteries use
chemical energy to create
an electric current. The
current is electrical
energy. It creates a beam of light that travels from
the remote to the television. The beam is light
energy. It turns on the television.
The television releases sound and light energy.
There is just a little bit of heat coming from the
television, too.
Eating lunch gives
you potential energy.

10

11


How does energy travel?
You know that moving objects contain
energy. But did you know that some energy
travels as waves? Sometimes these waves
are easy to see, such as ocean waves or
ripples of water. The bigger the wave or
ripple, the more energy it carries.

Some other forms of energy, such as
sound, also move as waves. You cannot see
these waves without special equipment.

crest

trough

Sound waves

You can measure how much energy is in a wave.
The bottom of a wave is called a trough. The top
of a wave is called the crest, or peak. Wide waves
have lots of space between the trough and crest.
They also have lots of energy.
The length of an energy wave can be measured
too. Find the space between two crests. The
shorter the space, the more energy that wave has.
Short waves have more energy than long waves.
That’s why a shortwave radio can pick up sounds
from very far away.

12

13


Heat Energy

The very tiny particles that make up all

three forms of matter are also moving. They are
moving because they have energy. This energy
is called thermal energy. Every time these tiny
particles move, they give off some heat.

14

Feel the top of a computer after
it has been on for a while. It will feel
Chocolate
very warm. The computer’s electrical
energy is giving off heat.
If you put a sheet of paper on top
of the computer, it will pick up some
of the heat. Thermal energy moves as
heat from a warmer object to a cooler
object. The paper will not get warmer
than the computer. It will only get as
warm as the computer.
Ice cubes
Thermal energy can change matter.
If you take away enough heat from a liquid,
you can freeze it. If you add enough heat
to a solid, you can melt it.

Melted chocolate

15

What path does light take?

Lantern fish

Light Energy
Light is energy that we can see. The Sun
produces light every day. Electricity is another
source of light. Light can also be made during
chemical changes. When fuel is burned, both
heat and light are created. A fire in a fireplace
keeps you warm. It also gives off a nice glow.
Chemical changes in some living things also
make light. Some ocean fish make their own
light because of chemicals in their bodies. It
is very dark deep in the ocean. The light some
ocean fish make helps them see. The lantern fish
got its name because it makes light in its body.
The light attracts both prey and mates.

16

Light takes the shortest and simplest
path from one point to another. Light does
not turn around corners. An object that
blocks light will cast a shadow behind it.
Not all objects block out light. Light
can pass through glass and clear water.
Scientists use different terms to
describe light.

Making
shadows

17


How does light change?
Even though light cannot avoid hitting an
object, it keeps moving after it does. Objects
reflect or redirect light. Objects with flat, smooth
surfaces reflect light very well. Light that bounces
off an object keeps moving, but in a different
direction. A mirror does this. You can see your
own reflection in a mirror because a lot of light
reflects off your face. If the light is right, you
might see yourself reflected in a lake too.

Objects that refract, or bend light, usually
make things appear differently from the way they
normally do. Things can look bigger or smaller
than they really are. They can look longer, shorter,
thinner, or wider too.
Light refracts because it moves at different
speeds through different materials. For example,
light moves more quickly through air than it does
through water.

18

19

Did you know that sunlight is made of
different colors? Red, orange, yellow, green,
blue, indigo, and violet are all found in sunlight.
Sometimes refraction causes the light to
separate into these colors. That’s when
you can see a rainbow.
When light hits an object, it will
reflect at least one of these colors.
Suppose a book has a blue cover in
the sunlight. This means the book
is reflecting blue light.

20

The book does not reflect colors other than blue.
It absorbs them, or takes them in. A white object
reflects all the colors of sunlight. A black object
absorbs all the colors. Have you ever noticed that
dark objects feel hotter in sunlight? That’s because
a lot of the absorbed sunlight turns into heat.
Polar bears reflect and absorb sunlight. Their fur
looks white because it reflects some of the sunlight.
However, underneath their fur polar bears have
black skin that absorbs the rest of the Sun’s light
and changes it to heat. This is part of the way that
polar bears stay warm during cold arctic winters.

21

Electrical Energy
The particles that make up matter have both
negative and positive electric charges. An
electric charge is a tiny amount of energy.
An object can be positively charged or
negatively charged. Positively charged objects
attract negatively charged ones. This means
that positively charged particles pull negatively
charged ones toward themselves. Objects with the
same charge repel one another. This means two
negatively charged particles will push each other
away.
Positive and negative charges
are everywhere. Magnets have
positive and negative charges.
Lightning is caused by
positive and negative
charges. Even your body
contains substances
that are positively and
negatively charged.

22

An electric current is
the flow of electric charges
from one place to another.
Electric circuits are

pathways that
control the flow
of the current.
Circuits are
usually made
with metal wires. This
is because metals are very good at moving
electricity from one place to another. When you
flip a switch, you are closing a circuit. Once the
circuit is closed, the electric current flows.
The electricity that runs through your home
travels on an alternating current. Alternating
currents change direction at certain times.
Some industries use direct current, which
does not change direction.
Electricity powers many of the
everyday objects we use. How many
can you name?

23


What did you learn?

Vocabulary

Glossary
absorb
electric charges
absorb

electric circuits
electriccharges
current
electric
kinetic energy
potential
energy
electric
circuits
reflect
refract
thermalcurrent
energy
electric

take in or suck up
tiny amounts of energy
controlled pathways that
electric charges travel on
the movement of
electrical energy

kinetic energy

the energy of motion

potential energy

energy stored in objects
and living things

Picture Credits
Every effort has been made to secure permission and provide appropriate credit for photographic material.
The publisher deeply regrets any omission and pledges to correct errors called to its attention in subsequent editions.

to bounce off an object and
Photo locators denoted as follows: Top (T), Center (C), Bottom (B), Left (L), Right (R), Background (Bkgd).
go in a different direction
6 Getty Images; 8 Getty Images; 9 Kindra Clineff/Index Stock Imagery; 10 VCL/Spencer Rowell/Getty Images; 14 Getty
reflect

Images; 16 David Wrobel/Visuals Unlimited; 21 Digital Vision.
Scott Foresman/Dorling Kindersley would also like to thank: 1, 13 Marconi Instruments Limited/DK Images; 19, 22 (R)
Stephen Oliver/DK Images.

refract

to bend and change
direction

Unless otherwise acknowledged, all photographs are the copyright © of Dorling Kindersley, a division of Pearson.

the total energy of all
thePrinted
particles
in ofmatter
Copyright © Pearson Education, Inc. All Rights Reserved.
in the United States
America.
thermal energy

ISBN: 0-328-13845-2

This publication is protected by Copyright, and permission should be obtained from the publisher prior to any
prohibited reproduction, storage in a retrieval system, or transmission in any form by any means, electronic,
mechanical, photocopying, recording, or likewise. For information regarding permission(s), write to
Permissions Department, Scott Foresman, 1900 East Lake Avenue, Glenview, Illinois 60025.

24

3 4 5 6 7 8 9 10 V010 13 12 11 10 09 08 07 06 05

1. Why does light refract?
2. Where do you get potential energy?
3. What are two examples of
the Sun’s energy?
4.

In this book
you have read about waves and
energy. Write to explain how you
can tell if a wave has a lot of
energy or a little energy. Use
the words trough and crest in
your answer.

5.

Main Idea and Supporting
Details Electrical charges can be

positive or negative. What details
from the book help you understand
how charges move?