scott foresman science, grade 3, leveled · pdf filescott foresman science 3.13 ... isbn...

Scott Foresman Science 3.13
Genre Comprehension Skill Text Features Science Content
Nonfi ction Main Idea and Supporting Details
Captions
Labels
Glossary
Energy
ISBN 0-328-13845-2

1. Why does light refract?
2. Where do you get potential energy?
3. What are two examples of the Suns 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?
What did you learn?Vocabularyabsorbelectric chargeselectric circuitselectric currentkinetic energypotential energyrefl ectrefractthermal energy
Picture CreditsEvery 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 toPermissions Department, Scott Foresman, 1900 East Lake Avenue, Glenview, Illinois 60025.
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EnergySuppose 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 youre off!
Your parents park the car at a beach parking lot. You walk to the beach, where you fi nd 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.
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The Sun is Earths main source of energy.
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 fi nd out how its energy powers and shapes life on Earth!
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The Suns energy has different forms. One form is heat. Heat energy is created by reactions inside the Sun. Heat travels to the Suns surface and then to Earth. It causes ice to melt and water to evaporate. The uneven heating of Earths 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.
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.
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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.
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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.
What is energy of motion?
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Playing and swimming are forms of kinetic energy.
Fast-moving water has a lot of kinetic energy. Many years ago, people fi gured out a way to use that energy. They built dams to speed up the fl ow 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 fi gured out how to make electricity from moving water. They built dams that create electricity. These dams change waters kinetic energy to electrical energy.
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Changing Forms of Energy
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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 cereals 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.
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Eating lunch gives you potential energy.

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.
How does energy travel?
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You can measure how much energy is in a wave. The bottom of a wave is called a trough. The to

scott foresman science, grade 3, leveled · pdf filescott foresman science 3.13 ... isbn...

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