i Twentieth-Century Science |Physics Decade by Decade 0i-xxiv_20CS-Physics-fm.indd i 5/10/07 1:40:17 PM 0i-xxiv_20CS-Physics-fm.indd ii 5/10/07 1:40:17 PM i Twentieth-Century Science |Physics Decade by Decade Alfred B. Bortz, Ph.D. Set Editor: William J. Cannon 0i-xxiv_20CS-Physics-fm.indd iii 5/10/07 1:40:17 PM For Alex, 21st-century grandson PHYSICS: Decade by Decade Copyright © 2007 by Alfred B. Bortz, Ph.D. 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 permis- sion in writing from the publisher. For information contact: Facts On File, Inc. An imprint of Infobase Publishing 132 West 31st Street New York NY 10001 ISBN-10: 0-8160-5532-7 ISBN-13: 978-0-8160-5532-6 Library of Congress Cataloging-in-Publication Data Bortz, Alfred B. Physics: decade by decade / Alfred B. Bortz p. cm. — (Twentieth-century science) Includes bibliographical references and index. ISBN 0-8160-5532-7 (acid-free paper) 1. Physics—History—20th century. 2. Physics—Study and teaching. I. Title. QC7.B58 2007 530.09′04—dc22 2006022921 Facts On File 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 Facts On File on the World Wide Web at http://www.factsonfile.com Text design by Dorothy M. Preston and Kerry Casey Cover design by Dorothy M. Preston and Salvatore Luongo Illustrations by Bobbi McCutcheon Photo Research by Elizabeth H. Oakes Printed in the United States of America VB Hermitage 10 9 8 7 6 5 4 3 2 1 This book is printed on acid-free paper. 0i-xxiv_20CS-Physics-fm.indd iv 5/10/07 1:40:18 PM Contents Preface . xi Acknowledgments . .xv Introduction . .xvii The Nineteenth-Century Clockwork Universe . .xvii The Atomic Theory of Matter . .xvii Electromagnetism and Light. xviii Reweaving the Fabric of Physics . xix Physics and Conservation Laws . .xx 1. 1901–1910: The Dawn of Modern Physics . 1 Curious Findings . .1 Milestones. .2 New Century, New Perspectives. .8 Quanta and the Photoelectric Effect. .8 Brownian Motion and the Reality of Atoms. .11 The Special Theory of Relativity . .11 The Divisible Atom . .18 Scientist of the Decade: Albert Einstein (1879–1955) . .22 New Techniques, Technologies, and Observations. .22 Further Reading . .24 2. 1911–1920: New Views of Matter . 27 The Discovery of the Nucleus. .27 Milestones. .28 The Bohr Model of the Atom . .30 Inside the Nucleus . .33 Atoms in Solids. .34 Astronomy and Cosmology . .35 The General Theory of Relativity . .36 The Discovery of Galaxies. .39 Cosmic Rays . .40 0i-xxiv_20CS-Physics-fm.indd v 5/10/07 1:40:18 PM New Theories, Techniques, and Technologies. .41 Scientist of the Decade: Ernest Rutherford (1871–1937) . .42 Superconductivity . .44 Continental Drift. .45 Further Reading . .45 3. 1921–1930: The Quantum Revolution . .48 Milestones. .48 From the Bohr Atom to Quantum Mechanics . .50 Understanding the Quantum Universe. .57 Relativity, Spin, Beta Decay, and Predicted Particles . .61 Subatomic Physics . .62 Stars, Galaxies, and Rockets . .63 Understanding Wave Functions . .64 Scientist of the Decade: Wolfgang Pauli (1900–1958) . .66 Further Reading . .66 4. 1931–1940: Particles and Politics . 69 Inside the Nucleus . .70 Milestones. .70 New Subatomic Particles. .74 Particle Accelerators. .76 Artificial Radioactivity and Nuclear Fission . .79 Other Developments in 1930s Physics . .84 Scientist of the Decade: Lise Meitner (1878–1968) . .86 Further Reading . .88 5. 1941–1950: Physics in a Time of War . 90 Milestones. .90 0i-xxiv_20CS-Physics-fm.indd vi 5/10/07 1:40:18 PM QED: Quantum Electrodynamics. .92 Nuclear Fission, “Big Science,” and the Bomb. .97 Cosmic Rays and Subatomic Particles. .104 Other Fields in Physics in the 1940s. .106 Scientist of the Decade: Richard Feynman (1918–1988) . .108 Further Reading . .110 6. 1951–1960: Physics and the Rise of New Technologies. 112 Milestones. .112 Solid-State Physics and Technology . .114 Electrical Conductors, Insulators, and Semiconductors. .117 Electron Energy Levels and Wave Functions in Solids . .118 Superconductivity. .124 Nuclear Physics and Technology. .126 The Subatomic Particle “Zoo” . .127 Other Developments in 1950s Physics and Technology . .129 Scientist of the Decade: John Bardeen (1908–1991) . .130 Further Reading . .132 7. 1961–1970: Explorations . 134 Milestones. .134 Fundamental Particles and Forces. .135 On the Other Hand . .140 The Flavorful Quark and the Strong “Color” Force . .142 Charm and the Electroweak Force . .147 Gauge Bosons, the Higgs Field, and the Origin of Mass. .148 New Particle Detectors . .148 Cosmological Evidence for the Big Bang . .150 Scientist of the Decade: Murray Gell-Mann (1929– ) . .152 Other Developments in 1960s Physics and Technology . .154 Further Reading . ..