Lise Meitner and the Discovery of Nuclear Fission Author(s): Ruth Lewin Sime Source: Scientific American , Vol. 278, No. 1 (JANUARY 1998), pp. 80-85 Published by: Scientific American, a division of Nature America, Inc. Stable URL: https://www.jstor.org/stable/10.2307/26057626 JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact [email protected]. Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at https://about.jstor.org/terms Scientific American, a division of Nature America, Inc. is collaborating with JSTOR to digitize, preserve and extend access to Scientific American This content downloaded from 129.2.19.102 on Mon, 18 Nov 2019 16:13:00 UTC All use subject to https://about.jstor.org/terms Lise Meitner and the Discovery of Nuclear Fission by Ruth Lewin Sime One of the discoverers of fission in 1938, Meitner was at the time overlooked by the Nobel judges. Racial persecution, fear and opportunism combined to obscure her contributions 80 Scientific American January 1998 Lise Meitner and the Discovery of Nuclear Fission Copyright 1997 Scientific American, Inc. This content downloaded from 129.2.19.102 on Mon, 18 Nov 2019 16:13:00 UTC All use subject to https://about.jstor.org/terms hen scientists first recog- Questions from nuclear physics initiated believed that history would be on her nized, in late 1938, that a the work. Data and assumptions from side. Fifty years later, it is. Wneutron could split an atom’s both chemistry and physics guided and core, the discovery came as a complete misguided their progress. And private Investigating Uranium surprise. Indeed, no physical theory had letters reveal that Meitner made essen- predicted nuclear fission, and its discov- tial contributions until the very end. orn and educated in Vienna, Lise erers had not the slightest foreknowl- By any normal standards of scientific BMeitner moved to Berlin in 1907 at edge of its eventual use in atomic bombs attribution, the Nobel committees should the age of 28. There she teamed up with and power plants. That much of the have recognized her influence. But in Otto Hahn, a chemist just her age, to story is undisputed. Germany the conditions were anything study radioactivity, the process by which The question of who deserved credit but normal. The country’s anti-Jewish one nucleus is transformed into another for the breakthrough, however, has long policies forced Meitner to emigrate, sep- by the emission of alpha or beta parti- been debated. Physicist Lise Meitner and arated her from her laboratory and pro- cles. Their collaboration was capped by two chemists, Otto Hahn and Fritz hibited her from being a co-author with their discovery in 1918 of protactini- Strassmann, conducted a four-year-long Hahn and Strassmann in reporting the um, a particularly heavy radioactive ele- investigation that resulted in the discov- fission result. Because of political op- ment. As their careers progressed, they ery of fission in their laboratory in Berlin. pression and fear, Hahn distanced him- remained equals scientifically and pro- Meitner fled Nazi Germany in 1938 to self and fission from Meitner and phys- fessionally: both were professors at the escape the persecution of Jews, and soon ics soon after the discovery took place. Kaiser Wilhelm Institute for Chemistry, after, Hahn and Strassmann reported the In time, the Nobel awards sealed these and each maintained an independent discovery. Meitner and her nephew, Otto injustices into scientific history. Recently section in the institute—his for radio- R. Frisch, published the correct theoreti- released documents show that the No- chemistry, hers for physics. cal interpretation of fission a few weeks bel committees did not grasp the extent During the 1920s, Hahn continued later. But the 1944 Nobel Prize in Chem- to which the result relied on both phys- developing radiochemical techniques, istry was awarded to Hahn alone. ics and chemistry, and they did not rec- whereas Meitner entered the new field That Strassmann did not get the No- ognize that Hahn had distanced himself of nuclear physics. Hahn later described bel with Hahn is probably because he from Meitner not on scientific grounds this period as a time when her work, was the junior investigator on the team, but because of political oppression, fear more than his, brought international and Nobel committees tend to favor se- and opportunism. recognition to the institute. Her promi- nior scientists. But Meitner and Hahn Other factors also served to margin- nence, and her Austrian citizenship, held equal professional standing. Why alize Meitner, including her outsider sta- shielded Meitner when Hitler came to was she excluded? Hahn offered what tus as a refugee in Sweden, a postwar power in 1933; unlike most others of became the standard account, which was unwillingness in Germany to confront Jewish origin, she was not dismissed uncritically accepted for many years. Nazi crimes, and a general perception— from her position. And although many According to him, the discovery had re- held much more strongly then than it is of her students and assistants were Nazi lied solely on chemical experiments that now—that women scientists were un- enthusiasts, Meitner found the physics were done after Meitner left Berlin. She important, subordinate or wrong. Pub- too exciting to leave. She was particu- and physics, he maintained, had noth- licly, Meitner said little at the time. Pri- larly intrigued by the experiments of En- ing to do with his success, except per- vately, she described Hahn’s behavior rico Fermi and his co-workers in Rome, haps to delay it. as “simply suppressing the past,” a past who began using neutrons to bombard Strassmann, who was very much in in which they had been the closest of elements throughout the periodic table. Hahn’s shadow, disagreed. He insisted colleagues and friends. She must have Fermi observed that when a neutron that Meitner had been their intellectual leader and that she remained one of them through her correspondence with Hahn, even after she left Berlin. The available documents support Strassmann’s view. Scientific publications show that the in- vestigation that led to the discovery of fission was intensely interdisciplinary. O COURTESY OF ARCHIV ZUR GESCHICHTE DER MAX-PLANCK-GESELLSCHAFT, BERLIN OF ARCHIV ZUR GESCHICHTE DER MAX-PLANCK-GESELLSCHAFT, O COURTESY LISE MEITNER (shown at left in about HOT 1930, at the age of 50) was regarded as , P AF one of the leading nuclear physicists of her day. Although she smoked and worked with radioactivity all her adult life, she lived to the age of 90. Otto Hahn and Meitner (right), photographed in their laboratory at the University of Berlin around 1910, were colleagues and good AIT © ATELIER LOTTE MEITNER-GR LOTTE AIT © ATELIER friends from 1907 until Meitner was BERLIN TESY OF ARCHIV ZUR GESCHICHTE DER MAX-PLANCK-GESELLSCHAFT, TR COUR POR forced to flee from Germany in 1938. Lise Meitner and the Discovery of Nuclear Fission Scientific American January 1998 81 Copyright 1997 Scientific American, Inc. This content downloaded from 129.2.19.102 on Mon, 18 Nov 2019 16:13:00 UTC All use subject to https://about.jstor.org/terms MEITNER’S PHYSICAL APPARATUS was used by the Berlin team from 1934 to 1938 for work that resulted in the dis- covery of nuclear fission. Beginning in the 1950s, it was displayed in the Deutsches Museum for some 30 years as the “Worktable of Otto Hahn,” with only a passing reference to Fritz Strass- mann and no mention of Meitner. COURTESY OF DEUTSCHES MUSEUM, MUNICH OF DEUTSCHES COURTESY though reluctant at first, agreed to help, and Fritz Strassmann, an analytical chemist from the institute, also joined the collaboration. The three were polit- ically compatible: Meitner was “non- Aryan,” Hahn was anti-Nazi, and Strassmann had refused to join the Na- tional Socialist–associated German Chemical Society, making him unem- ployable outside the institute. By the end of 1934, the team reported that the beta emitters Fermi observed reaction occurred, the targeted nucleus Fermi irradiated the heaviest known ele- could not be attributed to any other did not change dramatically: the incom- ment, uranium, with neutrons, he ob- known element and that they behaved ing neutron would most often cause the served several new beta emitters, none in a manner expected for transuranics: target nucleus to emit a proton or an al- with the chemical properties of uranium they could be separated out of the reac- ) pha particle, nothing more. Heavy ele- or the elements near it. Thus, he cau- tion mixture along with transition met- right ments, he found, favored neutron cap- tiously suggested that he had synthesized als, such as platinum and rhenium sul- ture. That is, a heavy nucleus would new elements beyond uranium. All over fides. Thus, like Fermi, the Berlin scien- ALIFORNIA ( gain an extra neutron; if radioactive, the the world, scientists were fascinated. tists tentatively suggested that these Y OF C heavier nucleus would invariably decay Meitner had been verifying Fermi’s activities were new elements beyond by emitting beta rays, which transformed results up to this point. The work per- uranium. As it turned out, the interpre- , UNIVERSIT it into the next higher element. When fectly suited her interests and expertise, tation was incorrect: it rested on two ORY and she was then in her assumptions—one from physics and one prime: one of the first women from chemistry—that would prove false PERIODIC TABLE of the 1920s and 1930s (below to enter the upper ranks of only several years later.