How Do Refrigerators Work? (science In The Real World)

How Do Refrigerators Work? by Christina Wilsdon Science and Curriculum Consultant: Debra Voege, M.A., Science Curriculum Resource Teacher Refrigerator_2print.indd 1 8/10/09 12:49:23 PM Science in the Real World: How Do Refrigerators Work? Copyright © 2010 by Infobase Publishing All rights reserved. No part of this book may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information storage or retrieval systems, without permission in writing from the publisher. For information contact: Chelsea Clubhouse An imprint of Chelsea House Publishers 132 West 31st Street New York NY 10001 Library of Congress Cataloging-in-Publication Data Wilsdon, Christina. Science in the real world : how do refrigerators work? / by Christina Wilsdon; science and curriculum consultant, Debra Voege. p. cm. Includes index. ISBN 978-1-60413-473-5 1. Refrigeration and refrigerating machinery—Juvenile literature. 2. Refrigerators—Juvenile literature. I. Title. TP492.2.W55 2010 621.5’7—dc22 2009001690 Chelsea Clubhouse books are available at special discounts when purchased in bulk quantities for businesses, associations, institutions, or sales promotions. Please call our Special Sales Department in New York at (212) 967-8800 or (800) 322-8755. You can find Chelsea Clubhouse on the World Wide Web at http://www.chelseahouse.com Developed for Chelsea House by RJF Publishing LLC (www.RJFpublishing.com) Text and cover design by Tammy West/Westgraphix LLC Illustrations by Spectrum Creative Inc. Photo research by Edward A. Thomas Index by Nila Glikin Photo Credits: 4, 13, 23: © Edward A. Thomas; 5: BILL ADAMS/Newhouse News Service /Landov; 6, 10, 11: iStockphoto; 7: Library of Congress LC-USZ62-67382; 17, 25, 28: Alamy; 21: Associated Press; 24: Library of CongressLC-USZ62-71467; 26: © JVPD/0003/ImageEnvision.com; 27: Library of Congress LC-USZ62-4553; 29: Shutterstock. Printed and bound in the United States of America Bang RJF 10 9 8 7 6 5 4 3 2 1 This book is printed on acid-free paper. All links and Web addresses were checked and verified to be correct at the time of publication. Because of the dynamic nature of the Web, some addresses and links may have changed since publication and may no longer be valid. Refrigerator_2print.indd 2 8/10/09 12:49:24 PM Table of Contents Keeping Cool............................................................ 4 How Food Spoils....................................................... 6 Refrigerators and Heat............................................ 8 Hot and Cold.......................................................... 10 Under Pressure...................................................... 12 The Evaporator: Low Pressure.............................. 14 The Compressor: High Pressure........................... 16 The Condenser: More High Pressure.................... 18 Back to the Evaporator.......................................... 20 Temperature Control............................................. 22 Refrigeration in the Past........................................ 24 Iceboxes.................................................................. 26 Electric Refrigerators............................................. 28 Glossary.................................................................. 30 To Learn More........................................................ 31 Index....................................................................... 32 Words that are defined in the Glossary are in bold type the first time they appear in the text. 5 Refrigerator_2print.indd 3 8/10/09 12:49:25 PM Keeping Cool W hat foods are in your refrigerator? Is there a carton of juice or milk? What about vegetables, fruits, meat, or cheese? All these foods have something in common: they spoil, or “go bad,