Rebecca E. Hirsch - Science Lab: Motion and Forces

Published in the United States of America

by Cherry Lake Publishing

Ann Arbor, Michigan

www.cherrylakepublishing.com

Printed in the United States of America

Corporate Graphics Inc

September 2011

CLFA09

Consultants: Peter Barnes, assistant scientist, University of Florida; Gail Saunders-Smith, associate professor of literacy, Beeghly College of Education, Youngstown State University

Photo credits: Paul Topp/Dreamstime, cover, 1; Dreamstime, 5; AP Images, 7; Levent Konuk/Shutterstock Images, 8; Aspen Photo/Shutterstock Images, 11; Richard Paul Kane/Shutterstock Images, 13; Fotolia, 14 (inset); Shutterstock Images, 14, 20; Ljupco Smokovski/Shutterstock Images, 16; Jarvis Gray/Shutterstock Images, 19; Victor Burnside/Dreamstime, 23; Brett Mulcahy/Shutterstock Images, 24; Mana Photo/Shutterstock Images, 27

Copyright 2012 by Cherry Lake Publishing

All rights reserved. No part of this book may be reproduced or utilized in any form or by any means without written permission from the publisher.

Library of Congress Cataloging-in-Publication Data

Hirsch, Rebecca E.

Science lab. Motion and forces / by Rebecca Hirsch.

p. cm. (Language arts explorer. Science lab)

Includes index.

ISBN 978-1-61080-205-5 ISBN 978-1-61080-294-9 (pbk.)

1. Force and energyJuvenile literature. 2. MotionJuvenile literature. I. Title. II. Title: Motion and forces.

QC73.4.H57 2011

531.6dc23

2011015130

Cherry Lake Publishing would like to acknowledge the work of The Partnership for 21st Century Skills. Please visit www.21stCenturySkills.org for more information.

You are being given a mission. The facts in What You Know will help you accomplish it. Remember the clues from What You Know while you are reading the story. The clues and the story will help you answer the questions at the end of the book. Have fun on this adventure!

You cant see forces, yet nothing happens without them. Forces are pushes or pulls, and they make objects move in different ways. Your mission is to investigate forces and how they create motion. What forces do you make? What forces are at work on you? How do forces affect the motion of cars, baseballs, bicycles, surfboards, and roller coasters? Read the facts in What You Know and start learning about the dynamic world of motion and forces.

Matter is anything you can touchwood, water, grass, metal, and even air. All matter is made of tiny particles called molecules.

Mass is the amount of matter in an object. A heavy object has a greater mass than a light object.

Forces are the pushes and pulls that act on people and object. You cant see forces, but you can feel them.

Speed tells us how fast an object is moving. It is the distance traveled in a certain period of time, such as miles per hour or feet per second.

Acceleration is a change in speed. It happens when an object slows down, speeds up, or changes direction.

Chlo Reynolds is a reporter from ScienceFUN magazine. She is part of a team that has been sent to investigate motion and forces. Carry out your mission by reading her journal.

We start our investigation in Minnesota with a visit to Dr. Bob MacAllister. He is an automotive engineer, a scientist who designs cars. He walks us through the big garage that is his laboratory.

The first thing you need to learn about motion is something called inertia , says Dr. MacAllister. Inertia means that an object that is not moving will not start moving by itself. It will stay at rest. Inertia also means that a moving object will not stop, speed up, or change direction unless something makes it. Anytime you see something change its speed or direction, you can be sure there is a force behind it.