Robert Gardner - Physics Experiments in Your Own Light Box

Published in 2016 by Enslow Publishing, LLC

101 W. 23rd Street, Suite 240, New York, NY 10011

Copyright 2016 by Robert Gardner

All rights reserved.

No part of this book may be reproduced by any means without the written permission of the publisher.

Cataloging-in-Publication Data

Gardner, Robert.

Physics experiments in your own light box / by Robert Gardner.

p. cm. (Design, build, experiment)

Includes bibliographical references and index.

ISBN 978-0-7660-6958-9 (library binding)

1. PhysicsExperimentsJuvenile literature. 2. Science projectsJuvenile literature. I. Gardner, Robert, 1929 II. Title.

QC33.G36 2016

530.078d23

Printed in the United States of America

To Our Readers: We have done our best to make sure all Web site addresses in this book were active and appropriate when we went to press. However, the author and the publisher have no control over and assume no liability for the material available on those Web sites or on any Web sites they may link to. Any comments or suggestions can be sent by e-mail to .

Portions of this book originally appeared in the book Physics Projects With a Light BoxYou Can Build.

Illustration Credits: Jonathan Moreno; pialhovik/iStock/Thinkstock (graph paper background throughout book).

Photo Credits: Enslow Publishing, LLC

Cover Illustrations: crazystocker/Shutterstock (background); g-stockstudio/iStock/Thinkstock (teenager).

Contents

Introduction

Science Fairs

The Scientific Method

Safety First

Chapter 1.Building a Light Box

1.1Making Light Box Masks

1.2Other Materials You Will Need

Chapter 2.Reflection of Light, Images, and Shadows

2.1The Law of Reflection

2.2Image in a Plane Mirror

2.3Mirror Images: A Model

2.4Three Images

2.5Making Many Images

2.6A Concave Mirror and Reflection

2.7A Different Kind of Image

2.8More Evidence That Light Travels in Straight Lines

2.9Distance, Light, and Shadows

2.10Brightness: Light Intensity

Chapter 3.Refraction: The Bending of Light

3.1Bend Light with Water

3.2Bend Light with a Convex Lens

3.3A Convex Lens Model

3.4A Convex Lens and Focal Length

3.5A Convex Lens: A Better Model

3.6Magnifying with a Convex Lens

3.7The Human Eye: A Model

3.8A Light Box Rainbow

Chapter 4.Light and Color

4.1Mixing Different Colors of Light

4.2Can a Shadow Have Colored Stripes?

4.3Primary Colors and Complementary Colors

4.4Colored Light on Colored Objects

4.5Color Analysis with a Diffraction Grating

Chapter 5.More About Light and Color

5.1Subtracting Colored Light

5.2Scattering Colored Light

5.3What Are Afterimages?

5.4Colored Shadow Mysteries

Appendix: Science Supply Companies

Further Reading

Web Sites

Index

Introduction

Without light, plants would be unable to make food. Without plants, which are at the base of the food chain, animals could not live. So you can see how light is Earths only external source of energy. It is vital to life.

It was Sir Isaac Newton (16431727) who first developed a satisfactory theory about light. It was Newton, too, who showed that sunlight could be separated into all the colors of the rainbow and then put back together to reform white light. Newton believed that light was made up of tiny, fast-moving particles. Later, other scientists carried out experiments that indicated that light was like waves. Today, we consider light as having properties of both waves and particles. Regardless of their true nature, the properties of light will become evident as you do the experiments in this book.

To investigate light, you will first build a light box. The light box and the materials that go with it will allow you to do experiments that will help you to understand light. The experiments involve reflection, refraction (the bending of light), and colored light, which lends so much beauty to the world. One nice thing about doing light experiments is that you can literally see the results.

If you find that you enjoy experimenting to learn about light, you may want to study physics in high school and college. Learning about light might even become part of your lifes work if you choose an occupation such as physicist, optician, optometrist, ophthalmologist, or optical technician.

At times, as you carry out the activities in this book, you may need a partner to help you. It would be best if you work with someone who enjoys experimenting with light as much as you do. In that way, you will both enjoy what you are doing. This book will alert you to any danger involved in doing an experiment. In some cases, to avoid danger, you will be asked to work with an adult. Please do so. We dont want you to take any chances that could lead to an injury.

Like any good scientist, you should record your ideas, sketches, notes, calculations, questions, and anything you can conclude from your investigations in a notebook. By so doing, you can keep track of the information you gather and the conclusions you reach. Keeping a good notebook will allow you to refer to things you have done and help you in doing other projects in the future.

SCIENCE FAIRS

Some of the investigations in this book contain ideas you might use for a science fair project. Those experiments are indicated with a symbol. However, judges at science fairs do not reward projects or experiments that are simply copied from a book. For example, a diagram of the electromagnetic spectrum would not impress most judges; however, finding unique ways to measure the wavelength of light from infrared to ultraviolet would certainly attract their attention.

Science fair judges tend to reward creative thought and imagination. It is difficult to be creative or imaginative unless you are really interested in your project; therefore, try to choose an investigation that appeals to you. Before you jump into a project, consider, too, your own talents and the cost of the materials you will need.

If you decide to use an experiment or idea found in this book for a science fair, you should find ways to modify or extend it. This should not be difficult because you will discover that new ideas come to mind as you carry out investigations. Ideas will come to you that could make excellent science fair projects, particularly because the ideas are your own and are interesting to you.