Vapor, Rain, And Snow: The Science Of Clouds And Precipitation (weatherwise)

THIS PAGE INTENTIONALLY LEFT BLANK S LERNER PUBLICATIONS COMPANY · MINNEAPOLIS Text copyright © 2011 by Paul Fleisher All rights reserved. International copyright secured. No part of this book may be reproduced, stored in a retrieval system, or transmitted in any form or by any means—electronic, mechanical, photocopying, recording, or otherwise—without the prior written permission of Lerner Publishing Group, Inc., except for the inclusion of brief quotations in an acknowledged review. Lerner Publications Company A division of Lerner Publishing Group, Inc. 241 First Avenue North Minneapolis, MN 55401 U.S.A. Website address: www.lernerbooks.com Library of Congress Cataloging-in-Publication Data Fleisher, Paul. Vapor, rain, and snow : the science of clouds and precipitation / by Paul Fleisher. p. cm. — (Weatherwise) Includes bibliographical references and index. ISBN 978–0–8225–7534–4 (lib. bdg. : alk. paper) 1. Clouds—Juvenile literature. 2. Precipitation (Meteorology)—Juvenile literature. I. Title.   QC921.35.F555 2011   551.57’6—dc22 2009041720 Manufactured in the United States of America 1 – PC – 7/15/10 eISBN: 978-0-7613-6328-6 | the science of the ATMOSPHERE | | CONTENTS | 4 Introduction 6 Chapter One 15 Chapter Two Water in the Air Clouds 26 Chapter Three 39 Chapter Four 44 45 45 46 47 Precipitation Rainbows, Halos, and Sun Dogs Glossary Selected Bibliography For Further Reading Websites Index | INTRODUCTION | W eather is what happens in the air around us. But a lot of weather is really about water. When we think about weather, we think about rain or snow. We think about clouds and humidity. Each of those involves a form of water. Air is a mixture of clear, colorless gases. Water vapor is one of those gases. (It is the gas form of water.) The amount of water vapor in the air is always changing. On humid days, the air contains a lot of water vapor. When the air is dry, it holds very little water vapor. 4 Water typically falls from the sky in the form of rain or snow. It eventually returns to the sky when it turns into water vapor. Meteorology is the science of weather. For meteorologists to understand weather, they have to know what happens to water in the air. They have to be able to measure the amount of water in the air. They have to recognize different kinds of clouds and the weather these clouds bring with them. They have to know about different types of precipitation, such as mist, rain, sleet, and snow. And they have to know how water vapor carries the sun’s energy from one part of the atmosphere to another. Introduction 5 | CHAPTER ONE | Water in the Air E arth has only a limited amount of water. That water is recycled again and again. Water vapor in the air comes from oceans, from the land, and even from the leaves of plants. Water falls back to the ground as rain or snow. Plants take in some of the water. A small amount is frozen into glaciers. Some water flows to streams, lakes, and rivers. It eventually flows back to the oceans, where it may become vapor again. This process is called the water cycle. Water moves through the water cycle in three different states. Ice is solid w