MODERNMODERN SCIENCESCIENCE 1896–1945 Ray Spangenburg Diane Kit Moser Modern Science: 1896–1945 Copyright © 2004, 1994 by Ray Spangenburg and Diane Kit Moser This is a revised edition of THE HISTORY OF SCIENCE FROM 1895 TO 1945 Copyright © 1994 by Ray Spangenburg and Diane Kit Moser 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 permission in writing from the publisher. For information contact: Facts On File, Inc. 132 West 31st Street New York NY 10001 Library of Congress Cataloging-in-Publication Data Spangenburg, Ray, 1939– Modern science, 1896–1945 / Ray Spangenburg and Diane Kit Moser.—Rev. ed. p. cm. — (History of science) Rev. ed. of: History of science from 1895 to 1945, c1994. Summary: Discusses major scientists and scientific issues and discoveries of the first half of the twentieth century. ISBN 0-8160-4854-1 1. Science—History—Juvenile literature. 2. Life sciences—History—Juvenile liter- ature. [1. Science—History.] I. Moser, Diane, 1944– II. Spangenburg, Ray, 1939– History of science from 1895 to 1945. III. Title. Q126.4.S64 2004 509′.04—dc22 2003022974 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 Erika K. Arroyo Cover design by Kelly Parr Illustrations by Sholto Ainslie Printed in the United States of America MP Hermitage 10 9 8 7 6 5 4 3 2 1 This book is printed on acid-free paper. In Memory of Morgan Sherwood and his love of the ever-human struggle to become rational n CONTENTS Preface viii Acknowledgments xiv Introduction xv PART I The Physical Sciences, 1896–1945 1 1 The New Atom: From X-Rays to the Nucleus 3 The Beginning of Modern Physics 4 The New Ray 6 Uranium’s Strange Gift 7 The Curies’ Quest 8 Amazing Electrons 13 Margaret Eliza Maltby and the Changing Face of Science 14 Plum Pudding 17 The Crocodile from New Zealand 17 2 The New Universe, Part One: Einstein and Relativity 21 The Ether Problem 21 The Quantum Mystery 24 Einstein and the Photoelectric Effect 28 Brownian Motion 32 The Special Theory 33 The General Theory 35 3 The New Universe, Part Two: The Quantum Surprise 40 Niels Bohr’s Atom 40 Pauli’s Exclusion Principle 45 Particle and Wave 47 Amalie Emmy Noether: Symmetry in Modern Physics 50 The Role of Uncertainty 52 4 New Observations of the Universe 54 Cosmic Rays 54 Understanding the Universe 57 Making Sense of Stars 57 Looking Inside Stars 59 Measuring the Universe 60 Classifying Stellar Spectra: Annie Jump Cannon 61 The Shape of the Home Galaxy 62 Hubble’s Better Yardstick 64 A Telescope Named Hubble 65 De Sitter’s Expanding Universe 66 5 The Atom Split Asunder: Science and the Bomb 68 A Walk in the Snow: Lise Meitner and Otto Frisch 68 Race against Hitler 74 Fermi’s Nuclear Reactor 75 The Path to Atom Smashing 78 The Manhattan Project 81 Hiroshima and Nagasaki 83 Aftermath 85 PART II The Life Sciences, 1896–1945 87 6 The Growth of Microbiology and Chemistry 89 A Question of Nerves 90 Buchner’s Brew 92 Body Chemistry 94 A Small World 97 Paul Ehrlich and the “Magic Bullet” 99 Sulfa, the “Wonder Drug,” and Penicillin 105 A Matter of Diet 108 New Focus on the Very Small: The Electron Microscope 112 7 Pursuing the Trails of Genetics and Heredity 115 Gregor Mendel 115 Mendel Rediscovered 120 Bateson and Gene Linkage 121 Morgan’s Fruit Flies 121 The Paths to DNA 124 Darwin and Mendel Combined 127 8 In Search of Ancient Humans 130 The Neandertals 132 Homo erectus 136 The Piltdown Hoax 141 African Bonanza 145 PART III Science and Society, 1896–1945 153 9 Medicine and the Machine Mongers 155 A Long Legacy 156 Crum’s Cure 158 A Healing Heel 159 10 A Growing Resource: Women in Science 163 The Curie Dynasty 165 Family and Science 166 Working Alone 168 Conclusion 172 Chronology 175 Glossary 187 Further Reading and Web Sites 191 Index 199 PREFACE What I see in Nature is a magnificent structure that we can com- prehend only very imperfectly, and that must fill a thinking per- son with a feeling of “humility.” —Albert Einstein SCIENCE, OF ALL HUMAN ENDEAVORS, is one of the greatest adventures: Its job is to explore that “magnificent structure” we call nature and its awesome unknown regions. It probes the great mys- teries of the universe such as black holes, star nurseries, and quasars, as well as the perplexities of miniscule subatomic parti- cles, such as quarks and antiquarks. Science seeks to understand the secrets of the human body and the redwood tree and the retrovirus. The realms of its inquiry embrace the entire universe and everything in it, from the smallest speck of dust on a tiny asteroid to the fleck of color in a girl’s eye, and from the vast structure of a far-off galaxy millions of light years away to the complex dynamics that keep the rings of Saturn suspended in space. Some people tend to think that science is a musty, dusty set of facts and statistics to be memorized and soon forgotten. Others con- tend that science is the antithesis of poetry, magic, and all things human. Both groups have it wrong—nothing could be more growth- oriented or more filled with wonder or more human. Science is con- stantly evolving, undergoing revolutions, always producing “new words set to the old music,” and constantly refocusing what has gone before into fresh, new understanding. Asking questions and trying to understand how things work are among the most fundamental of human characteristics, and the history of science is the story of how a varied array of individuals, viii Preface ix Looks can be deceiving. These two lines are the same length. teams, and groups have gone about finding answers to some of the most fundamental questions. When, for example, did people begin wondering what Earth is made of and what its shape might be? How could they find answers? What methods did they devise for coming to conclusions and how good were those methods? At what point did their inquiries become scientific—and what does that mean? Science is so much more than the strange test tubes and odd apparatus we see in movies. It goes far beyond frog dissections or the names of plant species that we learn in biology classes. Science is actually a way of thinking, a vital, ever-growing way of looking at the world. It is a way of discovering how the world works—a very particular way that uses a set of rules devised by scientists to help them also discover their own mistakes because it is so easy to mis- construe what one sees or hears or perceives in other ways. If you find that hard to believe, look at the two horizontal lines in the figure above. One looks like a two-way arrow; the other has inverted arrowheads. Which one do you think is longer (not includ- ing the “arrowheads”)? Now measure them both. Right, they are exactly the same length. Because it is so easy to go wrong in mak- ing observations and drawing conclusions, people developed a sys- tem, a “scientific method,” for asking “How can I be sure?” If you actually took the time to measure the two lines in our example, instead of just taking our word that both lines are the same length, then you were thinking like a scientist. You were testing your own observation. You were testing the information that both lines “are exactly the same length.” And you were employing one of the x Modern Science strongest tools of science to perform your test: You were quantify- ing, or measuring, the lines. More than 2,300 years ago, Aristotle, a Greek philosopher, told the world that when two objects of different weights were dropped from a height, the heaviest would hit the ground first. It was a com- monsense argument. After all, anyone who wanted to try a test could make an “observation” and see that if you dropped a leaf and a stone together that the stone would land first. Try it yourself with a sheet of notebook paper and a paperweight in your living room. (There is something wrong with this test. Do you know what it is?) However, not many Greek thinkers tried any sort of test. Why bother when the answer was already known? And, since they were philosophers who believed in the power of the human mind to simply “reason” such things out without having to resort to “tests,” they considered obser- vation and experiments intellectually and socially beneath them. Centuries later, though, Galileo Galilei came along, a brilliant Italian pioneer in physics and telescopic astronomy. Galileo liked to figure things out for himself, and he did run some tests, even though he had to work around some limitations. Like today’s scientists, Galileo was never content just to watch. He used two balls of differ- ent weights, a time-keeping device, and an inclined plane, or ramp. Accurate clocks and watches were not yet invented, but he worked around that problem by rigging his own device.