ffirs.qxd 10/13/04 3:27 PM Page i MMaadd aabboouutt MMooddeerrnn PPhhyyssiiccss ffirs.qxd 10/26/04 9:36 AM Page ii ffirs.qxd 10/13/04 3:27 PM Page iii MMaadd aabboouutt MMooddeerrnn PPhhyyssiiccss Braintwisters, Paradoxes, and Curiosities Franklin Potter and Christopher Jargodzki John Wiley & Sons, Inc. ffirs.qxd 10/13/04 3:27 PM Page iv This book is printed on acid-free paper. Copyright © 2005 by Franklin Potter and Christopher Jargodzki. All rights reserved Illustrations on pages 2, 4, 9, 26, 31, 134, and 161 copyright © 2005 by Tina Cash-Walsh. Published by John Wiley & Sons, Inc., Hoboken, New Jersey Published simultaneously in Canada Design and production by Navta Associates, Inc. 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Wiley also publishes its books in a variety of electronic formats. Some content that appears in print may not be available in electronic books. For more information about Wiley products, visit our web site at www.wiley.com. Library of Congress Cataloging-in-Publication Data: Potter, Frank, date Mad about modern physics : braintwisters, paradoxes and curiosities / Franklin Potter and Christopher Jargodzki. p. cm. Includes index. ISBN 0-471-44855-9 1. Physics--Popular works. I. Jargodzki, Christopher II. Title QC24.5.P68 2004 530—dc22 2004014941 Printed in the United States of America 10 9 8 7 6 5 4 3 2 1 ffirs.qxd 10/13/04 3:27 PM Page v To my late parents, who nourished my formative years and have now crossed that portal to another world. F. P. To my late grandmother—Zofia Lesinska, who instilled in me the idea that the visible world owes its being to the invisible one. C. J. ffirs.qxd 10/13/04 3:27 PM Page vi ftoc.qxd 10/13/04 3:29 PM Page vii Contents Preface. . . . . . . . . . . . . . . . . . . . . . . . . . ix Acknowledgments. . . . . . . . . . . . . . . . . . xii To the Reader . . . . . . . . . . . . . . . . . . . . . xiii Chapter 1 The Heat Is On . . . . . . . . . . . . . . . . . . . . 1 Chapter 2 Does Anybody Really Know What Time It Is?. . . . . . . . . . . . . . . . . . . . . . . . 11 Chapter 3 Crazy Circles . . . . . . . . . . . . . . . . . . . . . 19 Chapter 4 Fly Me to the Moon. . . . . . . . . . . . . . . . . 29 Chapter 5 Go Ask Alice. . . . . . . . . . . . . . . . . . . . . . 39 Chapter 6 Start Me Up . . . . . . . . . . . . . . . . . . . . . . 49 Chapter 7 A Whole New World. . . . . . . . . . . . . . . . . 63 Chapter 8 Chances Are. . . . . . . . . . . . . . . . . . . . . . 75 Chapter 9 Can This Be Real? . . . . . . . . . . . . . . . . . 91 Chapter 10 Over My Head. . . . . . . . . . . . . . . . . . . . . 105 Chapter 11 Crystal Blue Persuasion. . . . . . . . . . . . . 117 vii ftoc.qxd 10/13/04 3:29 PM Page viii Answers The Heat Is On. . . . . . . . . . . . . . . . . . . . . . 125 Does Anybody Really Know What Time It Is? . . . . . . . . . . . . . . . . . . . . . . . 139 Crazy Circles. . . . . . . . . . . . . . . . . . . . . . . 151 Fly Me to the Moon . . . . . . . . . . . . . . . . . . 164 Go Ask Alice . . . . . . . . . . . . . . . . . . . . . . . 181 Start Me Up. . . . . . . . . . . . . . . . . . . . . . . . 192 A Whole New World . . . . . . . . . . . . . . . . . . 206 Chances Are. . . . . . . . . . . . . . . . . . . . . . . . 224 Can This Be Real?. . . . . . . . . . . . . . . . . . . 241 Over My Head . . . . . . . . . . . . . . . . . . . . . . 257 Crystal Blue Persuasion . . . . . . . . . . . . . . 277 Index . . . . . . . . . . . . . . . . . . . . . . . . . . 287 viii Contents flast.qxd 10/13/04 3:31 PM Page ix Preface T his book of almost 250 puzzles begins where our first book, Mad About Physics: Braintwisters, Paradoxes, and Curiosities (2001) ended—with the physics of the late nineteenth and early twenti- eth centuries. The Michelson-Morley experiment of 1887, the challenges posed by atomic spectra and blackbody radiation, the unexpected discoveries of X-rays in 1895, radioactivity in 1896, and the electron in 1897 all loosened the protective belt of ad hoc hypothe- ses around the mechanistic physics the nineteenth century had so laboriously built. Anomalies and paradoxes abounded, ultimately necessitating a radical rethinking of the very foundations of physics and culminating in the theory of relativity and quantum mechanics. Numerous applications of these new and strange concepts followed very quickly as atomic and nuclear physics led to semiconductor devices on the small scale and nuclear energy on the large scale. There- fore we have developed a whole new set of challenges to tickle the minds of our scientifically literate readers, from science students to engineers to professionals in the sciences. The challenges begin with the classical problem of getting a cooked egg into a bottle through a narrow bottleneck and back out again and progress gradually to the famous aging-twin paradox of the theory of special relativity and eventually reach problems dealing with the large- scale universe. In between, we explore the nature of time and of space as well as how the world of films and television tends to sacrifice physics for the sake of entertainment. We also consider some of the more startling questions in relativity. For example, we ask whether a person can go on a space journey out to a star 7,000 light-years distant and return while aging only 40 years! And we certainly want to emphasize the practical applications of microphysics through an exam- ination of some properties of exotic fluids, unusual motors running on air or on random motion, as well as thermal, electrical, and photonic properties of materials in a challenging journey into the atomic world. ix