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1 Standards Preview Physical Sciences Standard Set 1. Physical Sciences 1. Energy and matter have multiple forms and can be changed from one form to another. As a basis for understanding this concept: 1.a. Students know energy comes from the Sun to Earth in the form of light. 1.c. Students know machines and living things convert stored energy to motion and heat. 1.d. Students know energy can be carried from one place to another by waves, such as water waves and sound waves, by electric current, and by moving objects. 1.b. Students know sources of stored energy take many forms, such as food, fuel, and batteries. Genre Comprehension Skill Text Features Science Content Nonfiction Main Idea and Details Captions Charts Diagram Glossary Forms and Properties of Energy Scott Foresman Science 3.1 ì<(sk$m)=cdfbig< +^-Ä-U-Ä-U ISBN by Lillian Duggan

2 Vocabulary compression wave electricity energy energy of motion friction stored 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. Unless otherwise acknowledged, all photographs are the copyright of Dorling Kindersley, a division of Pearson. by Lillian Duggan Photo locators denoted as follows: Top (T), Center (C), Bottom (B), Left (L), Right (R), Background (Bkgd). 6 Brand X Pictures; 8 Brand X Pictures; 19 (TL, BR) Getty Images, (TR, BL) Corbis, (Bkgd) Brand X Pictures. ISBN: 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 V

3 Energy Sources Energy is the ability to do work. You do work when you make something move. Carrying your books and walking to school are ways of doing work. Without energy, things cannot move, stretch, or grow. Physical and chemical changes can only happen with energy. The Sun provides most of the energy used on Earth. This energy reaches Earth as light and heat. It warms Earth to a temperature that living things need. The Sun s energy reaches Earth as heat and light. This energy allows living things to grow. Using Stored Energy The energy your body uses does not come directly from the Sun. It comes from stored energy in the food you eat. When digested food reaches your body parts, this energy is released. Stored energy is also found in batteries, as well as in fuels such as gasoline. Using Energy from Batteries Stored energy can be used up. Suppose you have a toy car that runs on a battery. When the car is turned on, the chemical energy in the battery changes into energy of motion. When you play with the car, the energy gets used up. Eventually, the battery runs out of energy and the car stops running. A battery-operated toy car changes chemical energy into energy of motion. 2 3

4 Getting Energy from Fuel When food is cooked on a charcoal grill, the burning charcoal gives off heat energy, which cooks the food, and light energy. The charcoal is a fuel. Coal, oil, natural gas, and gasoline are fuels. When a fuel burns, its chemicals change. Stored energy is released. The stored energy becomes heat and light energy. Oil and natural gas are used to heat homes. The fuel is burned in a furnace. Burning the fuel causes heat energy to be released. The heat energy warms the air inside the house. Heat energy can also be used to cook food. The chemicals in charcoal release stored energy when the charcoal is burned. Getting Energy from Food Your body needs energy to grow, play, learn, and stay at the right temperature. You get that energy from food. Food has stored energy. When you eat, your body breaks down food into different substances. Some of the substances are carried to your muscles by your blood. Your muscles change the substances into energy of motion and heat energy. You use the energy of motion to run and play. The energy of heat is used to keep your body warm. Energy from food allows these athletes to run and kick the soccer ball. 4 5

5 Energy s Changing Forms Energy constantly changes forms. These changes happen in living and nonliving things. A moving object has energy of motion. It carries its energy of motion as it moves. An object that is not moving does not have energy of motion. Some energy changes are caused by machines. A toaster changes electrical energy into heat energy. Forms of Energy Chemical Motion Chemical energy holds together particles of matter, including those that make up food. It gives our bodies energy. Energy of motion makes objects move. Swinging changes stored energy into energy of motion. The car s engine changes the chemical energy in gasoline to energy of motion. Electrical Electrical energy moves through wires made of certain metals. It provides power to run electrical appliances in homes. Light Light energy from the Sun is used by plants to make food. Other forms of energy are changed into light to help people see. Thermal Thermal energy makes particles of matter move faster. We feel thermal energy as heat. 6 7

6 Transferring Energy of Motion A moving object has energy of motion. If it hits another object, the energy is transferred, or moved, to the other object. The second object starts to move, but the first object slows down or even stops. Suppose you are playing with a set of toy trains on a track. You push one train and let go. It bumps into another train. The second train begins to move, while the first train gradually stops moving. The energy of motion of the first train is transferred to the second train. The total amount of energy does not change. Friction When a moving object touches another object, some energy of motion changes into heat energy. Friction causes this change. It reduces a moving object s energy of motion. This causes the object to slow down. Suppose you are riding a bicycle. Your bike will keep moving for a while after you have stopped pedaling. But soon the bike will slow down and stop. The contact between the tires and the road causes friction. Some of the bike s energy of motion becomes heat. When the white ball hits the yellow ball, its energy of motion is transferred. To overcome the force of friction, you must keep pedaling. 8 9

7 Ways that Energy Moves Ocean waves carry a great deal of energy. As energy is moving through ocean water, the energy moves forward. The water itself moves up and down. When you shake sand out of a beach towel, the towel moves up and down as waves pass through it. But the towel does not move forward. In a water wave, the water moves up and down. But it does not move forward. Making Water Waves If you visit a lake or pond, you can see how energy moves in water waves. Find an area where the water is still and there is no wind. Gently place two lightweight sticks on the water. Then toss a rock in the water near the sticks. The rock will create waves in the water. As the waves move near the sticks, the sticks will move up and down. They might also move from side to side a little. But notice that the sticks do not leave the spot where you placed them. The waves move the water in this pond up and down, but not from one place to another. The more energy a wave has, the larger it is

8 How Sound Waves Move Sound waves carry energy produced by vibrations. When you knock on a door, it vibrates, causing the surrounding air to vibrate. These vibrations push the air particles together. Then the air particles move apart. The back-and-forth movement of particles makes a kind of wave called a compression wave. Sound waves are compression waves. How We Hear Sound The sound waves produced by a knock on the door or the chirping of a bird quickly reach your eardrum. Your eardrum is a thin layer of skin inside your ear. Sound waves cause your eardrum to vibrate. Small bones next to your eardrum then begin to vibrate as well. Then the sound energy is changed into another kind of signal, which travels to your brain. The bird or the door causes these changes without actually touching your ear. The spring s parts are pushed together and then move apart as energy flows through it. Sound waves travel in a similar way. When a bird chirps, its throat and the air around it vibrate. You hear the vibrations as sound. The parts of your inner ear pick up sound waves, allowing you to hear

9 How Earthquake Waves Move Look at the picture below. It shows earthquake waves passing through the ground. In real life, you cannot see earthquake waves. But like ocean waves, earthquake waves have lots of energy. This energy can cause damage. Earthquakes are caused by sudden movements of Earth s crust. These movements cause vibrations in the ground. The vibrations travel in waves. They can cause buildings to fall and roads to crumble. When an earthquake hits, it releases lots of energy. The energy gets carried by earthquake waves. Earthquakes cause three different kinds of waves. Therefore, the energy of earthquakes travels in three different ways. One kind of earthquake wave is similar to a sound wave. It pushes on the ground as it travels. The ground then moves back. Another kind is like a water wave. It causes the ground to shake up and down. And the third kind shakes the ground from side to side. Earthquakes cause the greatest damage to buildings closest to the starting point. The waves gradually lose energy as they travel. But they can be felt hundreds of kilometers away from where they begin. An earthquake released huge waves of energy that damaged these homes. earthquake waves 14 15

10 Electricity in Our Lives Your alarm clock tells you it is time to start your day. You use the toaster to make breakfast. You study during the evening by the light of a lamp. Throughout your entire day, you are using electricity, or electrical energy that can flow as a charge through a wire. Electrical energy is made in power plants. Power plants use fossil fuels, water, wind, or the heat from nuclear fuel to make electrical energy. The energy is carried in wires as electricity to your home. Moving electricity is called electric current. After the electricity reaches your home, it is changed into the energy of heat, light, and motion. The type of energy that electricity becomes depends on the kind of machine or appliance that uses it. Transmission Wires Electricity flows through wires. The wires connect the power plant to your home. Power Source Electrical energy is made in a power plant. Power Destination Electricity flows through wires to electrical outlets in your home. Electricity flows into an appliance after the appliance is plugged into an outlet

11 Ways We Use Electricity If you have been camping, you know what it is like to use only a small amount of electricity. Without electrical wires and outlets, television sets, refrigerators, and hair dryers do not work. These things change electrical energy into a form people can use. They allow us to get information, keep our food cool, and dry our hair. Humans have spent a lot of time and money developing ways to make electricity. We use the energy of moving water and the heat of burning fuel to generate electricity. Nuclear power stations change the heat made by special fuel into electricity. Even the energy in sunlight and wind can be used to produce electricity. Campers often have to get by with little electricity. Sources of Electrical Power These solar cells change sunlight energy into electrical power. Coal is burned to produce heat energy at this electric power plant. The heat energy is changed into electrical power. The energy of moving water is used to produce electricity at this power station. Nuclear energy is used to produce electrical power at this plant. These wind turbines change wind energy into electricity

12 Glossary compression wave electricity energy energy of motion friction stored energy a wave that carries energy by squeezing particles together and then letting them spread apart electrical energy that moves through wires the ability to do work; ability to make things move, stretch, or grow; or cause change the energy carried by moving objects what changes energy of motion into heat energy energy in food, fuel, and batteries that can be changed to motion, light, or heat What did you learn? 1. Where does the energy your body uses come from? 2. What happens when a fuel burns? 3. How does energy of motion get transferred? 4. Write a paragraph that describes what friction is and give an example of how it works. Include a topic sentence and simple supporting facts and details. 5. Main Idea and Details What is the main idea of page 15? What details support it? 20