Claybourne - Secrets of Light

ANNA CLAYBOURNE

E-book published in 2012 by Encyclopdia Britannica, Inc., in association with Arcturus Publishing Limited, 26/27 Bickels Yard, 151-153 Bermondsey Street, London SE1 3HA. Britannica, Encyclopdia Britannica, and the Thistle logo are registered trademarks of Encyclopdia Britannica, Inc.

ISBN 978-1-61535-633-1 (e-book)

This edition first published in 2011 in the United States of America
by MARSHALL CAVENDISH BENCHMARK
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Copyright 2010 Arcturus Publishing Limited

This publication represents the opinions and views of the author based on Anna Claybournes personal experience, knowledge, and research. The information in this book serves as a general guide only. The author and publisher have used their best efforts in preparing this book and disclaim liability rising directly and indirectly from the use and application of this book.

All rights reserved. No part of this publication 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 the copyright owner.

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Photo acknowledgments: Corbis: cover cityscape (Jon Arnold/JAI), pp 5 (Henry Watkins & Yibran Aragon/Reuters), 11tl (Fred Hirschmann/Science Faction), 29tl (DLILLC); Getty Images: pp 9 (SSPL), 10 (SSPL), 15 (Gandee Vasan), 22 (James Jordan Photography); IStockphoto: cover fibre optics (Henrik Jonsson), pp 1 (The-Tor), 6 (diane39), 16 (Pillon), 17 (Julian Barkway), 25tl (Gene Chutka); NASA: pp 7br, 20; NHPA: p 23 (Photo Researchers); Science Photo Library: p 21 (Larry Landolfi); Shutterstock Images: pp 7tl (Anton Prado), 8 (fotoadrenalina), 13 (Christian Musat), 18 (Ilja Mak), 19 (Achtin), 27 (Darko Kovacevic), 29br (Christopher Futcher); Flavio Takemoto: cover background; Wikimedia Commons: pp 4 (Honzasoukup), 25b (Hideki Kimura, Kohei Sagawa), 26 (Joseph Nicphore Nipce).

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Library of Congress Cataloging-in-Publication Data

Claybourne, Anna.
Secrets of light / Anna Claybourne.
p. cm. -- (Science secrets)
Includes bibliographical references and index.
1. Light--Juvenile literature. I. Title.
QC360.C5684 2011
535--dc22

2010003941

1 3 6 5 4 2

Light is everywhere. Every morning sunlight fills the sky, and at night we switch on the electric lights in our homes. Light shines from our cell phones and TVs and from our streets and our cities.

Humans, plants, and animals all need light to live. Without it, we wouldnt be able to see. Even worse, we wouldnt have any food, and there would be no life on Earth.

Early morning sunlight streams through the trees in a park in central India. The Sun is our main source of natural light.

DAY AND NIGHT

The place where you live cannot be in daylight all of the time, because Earth spins. When your part of the world is turned away from the Sun, it is nighttime. See for yourself how night and day happen.

You will need:

a ball or globe a sticker a flashlight or small lamp

1. Place the sticker on the ball to mark where you live.

2. Darken the room as much as you can. Shine the light at the ball to act as the Sun.

3. Slowly spin the ball around. Your home moves into the light (daytime), then away from the light (nighttime).

Divers use flashlights to explore a flooded cave system in Mexico.

Light is a strange and amazing form of energylike heat, electricity, and sound. What is light exactly, and where does it come from?

How far and how fast does light travel? How do our eyes see it, and how do animals and plants use it? Youll find the answers to all these questions in this book.

Light is a kind of energy. Energy is the power to do work or to make things happen. There are many forms of energy, and one form can change into another.

Light glows from objects when another kind of energy changes into light that we can see. For example, a candle contains chemicals that store energy. When you light it, the chemicals burn and some of the chemical energy turns into light energy.

Something that gives out light is called a light source. Candles, electric lights, and stars are all light sources. There are even some animals that produce their own light.