Genre Comprehension Skill Text Features Science Content Nonfi ction Cause and Effect • Captions • Glossary Forces and Motion Scott Foresman Science 2.1 Standards Preview Standard Set 1. Physical Sciences 1. The motion of objects can be observed and measured. As a basis for understanding this concept: 1.a. Students know the position of an object can be described by locating it in relation to another object or to the background. 1.b. Students know an object’s motion can be described by recording the change in position of the object over time. 1.c. Students know the way to change how something is moving is by giving it a puash or a pull. The size of the change is related to the strength, or the amount of force, of the push or pull. 1.d. Students know tools and machines are used to apply pushes and pulls (forces) to make things move. 1.e. Students know objects fall to the ground unless something holds them up. 1.f. Students know magnets can be used to make some objects move without being touched. ISBN 0-328-23493-1 ì<(sk$m)=cdejdg< +^-Ä-U-Ä-U 23493_CVR.indd Cover123493_CVR.indd Cover1 2/1/06 1:34:59 PM2/1/06 1:34:59 PM Physical Sciences by Mary Beth Spann 23493_CVR.indd Cover223493_CVR.indd Cover2 2/1/06 1:35:07 PM2/1/06 1:35:07 PM Vocabulary attract force friction gravity motion repel 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. Photo locators denoted as follows: Top (T), Center (C), Bottom (B), Left (L), Right (R), Background (Bkgd). Opener: ©Michael Dunning/Getty Images; 8 ©AFP/Getty Images; 9 ©Chapman/NewSport/Corbis; 11 ©Mike Brinson/ Getty Images; 12 ©Nation Wong/Corbis. ISBN: 0-328-23493-1 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. 1 2 3 4 5 6 7 8 9 10 V010 13 12 11 10 09 08 07 06 23493_CVR.indd Cover323493_CVR.indd Cover3 1/6/06 5:00:11 PM1/6/06 5:00:11 PM by Mary Beth Spann 23493_001-020.indd 123493_001-020.indd 1 1/6/06 9:57:30 AM1/6/06 9:57:30 AM How can you describe position? Look at the picture. The boys are in front of the goal. The bushes are behind the goal. In front of and behind tell position. Position tells where something is. The coach is to the right of the goal. 2 23493_001-020.indd 223493_001-020.indd 2 1/6/06 9:57:34 AM1/6/06 9:57:34 AM You can also use the background to describe position. There are bushes in the background. The goal is in front of the bushes. We measure to fi nd distance. We use centimeters and meters. The ball and the goal are about 5 meters apart. What else can you measure on the soccer fi eld? 3 23493_001-020.indd 323493_001-020.indd 3 1/6/06 9:57:40 AM1/6/06 9:57:40 AM 4 What is motion? Motion is the act of moving. Things move in different ways. Some things move in straight lines. Some things move back and forth. Some things move around and around. The car and the bicycle are in motion. 23493_001-020.indd 423493_001-020.indd 4 1/6/06 9:57:42 AM1/6/06 9:57:42 AM Motion has speed and direction. Push your bicycle pedals to change speed. Turn the handlebars to change direction. The bicycle moved for 10 minutes. The car moved for 10 minutes. The car moved farther than the bicycle. Is the car or bicycle farther from the library? 5 23493_001-020.indd 523493_001-020.indd 5 1/6/06 9:57:48 AM1/6/06 9:57:48 AM 6 Measuring Motion You can fi nd out how far something moves. How can you do that? You can measure. You can measure how far the truck goes. 23493_001-020.indd 623493_001-020.indd 6 1/6/06 9:57:51 AM1/6/06 9:57:51 AM 7 Roll a toy truck down a ramp. Mark where it stops. Now make the ramp a little higher. Roll the truck down again. Mark where it stops. How far did the truck go each time? 23493_001-020.indd 723493_001-020.indd 7 1/6/06 9:57:53 AM1/6/06 9:57:53 AM 8 Force Force is a push or a pull that can make something move. Force changes an object’s speed and direction. An object needs a push or a pull to move. Objects can speed up with a push or a pull. Or they can slow down. Tapping a ball takes little force. 23493_001-020.indd 823493_001-020.indd 8 1/6/06 9:57:53 AM1/6/06 9:57:53 AM 9 It takes more force to move something farther. Tapping a ball moves it a little bit. Kicking the ball moves it farther. Heavier things need more force to be moved. Kicking a ball takes more force. 23493_001-020.indd 923493_001-020.indd 9 1/6/06 9:58:03 AM1/6/06 9:58:03 AM 10 What is friction? What slows down a kicked ball? What makes it stop? Friction slows and stops things. Friction slows the ball. Friction makes the ball stop. 23493_001-020.indd 1023493_001-020.indd 10 1/6/06 9:58:07 AM1/6/06 9:58:07 AM 11 A bicycle moves faster on a smooth road. It moves slower on bumpy grass. Friction between the tires and grass slows the tires. There is more friction when you ride your bicycle over grass. 23493_001-020.indd 1123493_001-020.indd 11 1/6/06 9:58:11 AM1/6/06 9:58:11 AM 12 How can tools and machines make things move? Tools and machines help us do jobs. Tool and machines can push, pull, and move things. A hammer is a tool. It can help push a nail into wood. The hammer uses force to push the nail. 23493_001-020.indd 1223493_001-020.indd 12 1/6/06 9:58:14 AM1/6/06 9:58:14 AM 13 Using Tools and Machines The wagon is a machine. Wagons can move heavy things. They can move many things at once. A wagon can help you move many toys at once. 23493_001-020.indd 1323493_001-020.indd 13 1/6/06 9:58:17 AM1/6/06 9:58:17 AM 14 What is gravity? Why do things fall back to Earth? Gravity pulls things down. Gravity pulls things toward Earth’s center. The pull of gravity makes this car fall. 23493_001-020.indd 1423493_001-020.indd 14 1/6/06 9:58:18 AM1/6/06 9:58:18 AM 15 Gravity pulls harder on heavy things. A car is heavier than a ball. Gravity pulls harder on a car than on the ball. Gravity keeps the bear on the table. It keeps the table on the ground. 23493_001-020.indd 1523493_001-020.indd 15 1/6/06 9:58:21 AM1/6/06 9:58:21 AM 16 What are magnets? Magnets can push things. They can attract things that are metal. Attract means to pull toward. Magnets can also repel other magnets. Repel means to push away. This magnet attracts metal paper clips. 23493_001-020.indd 1623493_001-020.indd 16 1/6/06 9:58:22 AM1/6/06 9:58:22 AM 17 A magnet has two poles. Each pole has a strong push and pull. Like poles repel each other. Unlike poles attract each other. 23493_001-020.indd 1723493_001-020.indd 17 1/6/06 9:58:26 AM1/6/06 9:58:26 AM [...]... pattern was made with a magnet and iron 19 What did you learn? Glossary attract pull toward 1 What are some of the different ways things can move? force a push or a pull that makes something move 2 Name one tool and one machine that you learned about friction a pull that makes a moving object slow down or stop moving gravity a force that pulls things toward the center of Earth motion the act of moving repel... slow down or stop moving gravity a force that pulls things toward the center of Earth motion the act of moving repel push away 20 3 Force, friction, and gravity are vocabulary words Group them into two sentences that tell how they are related 4 Cause and Effect What causes the tires on a bicycle to slow down on bumpy grass? What is the effect of this? . ction Cause and Effect • Captions • Glossary Forces and Motion Scott Foresman Science 2.1 Standards Preview Standard Set 1. Physical Sciences 1. The motion of objects can be observed and measured AM 4 What is motion? Motion is the act of moving. Things move in different ways. Some things move in straight lines. Some things move back and forth. Some things move around and around. The car and the. bicycle are in motion. 23493_001-020.indd 423493_001-020.indd 4 1/6/06 9:57:42 AM1/6/06 9:57:42 AM Motion has speed and direction. Push your bicycle pedals to change speed. Turn the handlebars to