Fritz Strassmann

Friedrich Wilhelm "Fritz" Strassmann (German: Straßmann; 22 February 1902 – 22 April 1980) was a German chemist who, with Otto Hahn in early 1939, identified barium in the residue after bombarding uranium with neutrons, results which, when confirmed, demonstrated the previously unknown phenomenon of nuclear fission.

Fritz Strassmann
Friedrich Wilhelm Strassmann

22 February 1902
Died22 April 1980 (aged 78)
Known forNuclear fission
AwardsEnrico Fermi Award (1966)
Scientific career
FieldsPhysicist, Chemist

Life and career

Born in Boppard, he began his chemistry studies in 1920 at the Technical University of Hannover and earned his Ph.D. in 1929. He did his Ph.D. work on the solubility of iodine gaseous carbonic acid.

Strassmann started an academic career because the employment situation in the chemical industry was much worse than at the universities at that time.

Strassmann worked at the Kaiser Wilhelm Institute for Chemistry in Berlin-Dahlem, from 1929.

In 1933 he resigned from the Society of German Chemists when it became part of a Nazi-controlled public corporation. He was blacklisted. Otto Hahn and Lise Meitner found an assistantship for him at half pay. Strassmann considered himself fortunate, for "despite my affinity for chemistry, I value my personal freedom so highly that to preserve it I would break stones for a living." During the war he and his wife Maria Heckter Strassmann concealed a Jewish friend in their apartment for months, putting themselves and their three-year-old son at risk.

Strassmann's expertise in analytical chemistry was employed by Hahn and Meitner in their investigations of the products of bombarding uranium with neutrons. In December 1938, Hahn and Strassmann sent a manuscript to Naturwissenschaften reporting they had detected the element barium after bombarding uranium with neutrons;[1] Frisch confirmed this experimentally on 13 January 1939.[2] In 1944, Hahn received the Nobel Prize for Chemistry for the discovery of nuclear fission, although Fritz Strassmann had been acknowledged as an equal collaborator in the discovery.[3]

From 1939 to 1946 he contributed to research at the Kaiser-Wilhelm Institute on the fission products of thorium, uranium, and neptunium. In 1946 he became professor of inorganic chemistry at the University of Mainz and 1948 director of the newly established Max Planck Institute for Chemistry. He later founded the Institute for Nuclear Chemistry.

In 1957 he was one of the Göttingen Eighteen, who protested against the Adenauer government's plans to equip the Bundeswehr, Western Germany's army, with tactical nuclear weapons.

In 1966 President Johnson honored Hahn, Meitner and Strassmann with the Enrico Fermi Award. The International Astronomical Union named an asteroid after him: 19136 Strassmann.

In 1985 Fritz Strassmann was recognized by Yad Vashem Institute in Jerusalem as Righteous Among the Nations (חסיד אמות העולם) for hiding, together with his wife, a Jew in their home, risking their own life.

On 22 April 1980 Strassmann died in Mainz.

Internal report

The following was published in Kernphysikalische Forschungsberichte (Research Reports in Nuclear Physics), an internal publication of the German Uranverein. Reports in this publication were classified Top Secret, they had very limited distribution, and the authors were not allowed to keep copies. The reports were confiscated under the Allied Operation Alsos and sent to the United States Atomic Energy Commission for evaluation. In 1971, the reports were declassified and returned to Germany. The reports are available at the Karlsruhe Nuclear Research Center and the American Institute of Physics.[4][5]

  • Otto Hahn and Fritz Straßmann: Zur Folge nach der Entstehung des 2,3 Tage-Isotops des Elements 93 aus Uran G-151 (27 February 1942)


  • Fritz Straßmann: "Über die Löslichkeit von Jod in gasförmiger Kohlensäure", Zeitschrift f. physikal. Chemie. Abt. A., Bd. 143 (1929) and Ph.D. thesis Technical University of Hannover, 1930
  • Fritz Krafft: Im Schatten der Sensation. Leben und Wirken von Fritz Straßmann; Verlag Chemie, 1981
  • Hentschel, Klaus (Editor) and Ann M. Hentschel (Editorial Assistant and Translator): Physics and National Socialism: An Anthology of Primary Sources (Birkhäuser, 1996)
  • Walker, Mark: German National Socialism and the Quest for Nuclear Power 1939–1949 (Cambridge, 1993) ISBN 0-521-43804-7


  1. ^ O. Hahn and F. Strassmann Über den Nachweis und das Verhalten der bei der Bestrahlung des Urans mittels Neutronen entstehenden Erdalkalimetalle (On the detection and characteristics of the alkaline earth metals formed by irradiation of uranium with neutrons), Naturwissenschaften Volume 27, Number 1, 11-15 (1939). The authors were identified as being at the Kaiser-Wilhelm-Institut für Chemie, Berlin-Dahlem. Received 22 December 1938.
  2. ^ O. R. Frisch Physical Evidence for the Division of Heavy Nuclei under Neutron Bombardment, Nature, Volume 143, Number 3616, 276-276 (18 February 1939) Archived January 23, 2009, at the Wayback Machine. The paper is dated 17 January 1939. [The experiment for this letter to the editor was conducted on 13 January 1939; see Richard Rhodes The Making of the Atomic Bomb 263 and 268 (Simon and Schuster, 1986).]
  3. ^ Per F Dahl (1 January 1999). Heavy Water and the Wartime Race for Nuclear Energy. CRC Press. pp. 73–. ISBN 978-0-7503-0633-1.
  4. ^ Hentschel and Hentschel, 1996, Appendix E; see the entry for Kernphysikalische Forschungsberichte.
  5. ^ Walker, 1993, 268-274.

External links

Atomic Age

The Atomic Age, also known as the Atomic Era, is the period of history following the detonation of the first nuclear ("atomic") bomb, Trinity, on July 16, 1945, during World War II. Although nuclear chain reactions had been hypothesized in 1933 and the first artificial self-sustaining nuclear chain reaction (Chicago Pile-1) had taken place in December 1942, the Trinity test and the ensuing bombings of Hiroshima and Nagasaki that ended World War II represented the first large-scale use of nuclear technology and ushered in profound changes in sociopolitical thinking and the course of technology development.

While atomic power was promoted for a time as the epitome of progress and modernity, entering into the nuclear power era also entailed frightful implications of nuclear warfare, the Cold War, mutual assured destruction, nuclear proliferation, the risk of nuclear disaster (potentially as extreme as anthropogenic global nuclear winter), as well as beneficial civilian applications in nuclear medicine. It is no easy matter to fully segregate peaceful uses of nuclear technology from military or terrorist uses (such as the fabrication of dirty bombs from radioactive waste), which complicated the development of a global nuclear-power export industry right from the outset.

In 1973, concerning a flourishing nuclear power industry, the United States Atomic Energy Commission predicted that, by the turn of the 21st century, one thousand reactors would be producing electricity for homes and businesses across the U.S. However, the "nuclear dream" fell far short of what was promised because nuclear technology produced a range of social problems, from the nuclear arms race to nuclear meltdowns, and the unresolved difficulties of bomb plant cleanup and civilian plant waste disposal and decommissioning. Since 1973, reactor orders declined sharply as electricity demand fell and construction costs rose. Many orders and partially completed plants were cancelled.By the late 1970s, nuclear power had suffered a remarkable international destabilization, as it was faced with economic difficulties and widespread public opposition, coming to a head with the Three Mile Island accident in 1979, and the Chernobyl disaster in 1986, both of which adversely affected the nuclear power industry for many decades.

Enrico Fermi Award

The Enrico Fermi Award is an award honoring scientists of international stature for their lifetime achievement in the development, use, or production of energy. It is administered by the U.S. government's Department of Energy. The recipient receives $50,000, a certificate signed by the President and the Secretary of Energy, and a gold medal featuring the likeness of Enrico Fermi.

Fission barrier

In nuclear physics and nuclear chemistry, the fission barrier is the activation energy required for a nucleus of an atom to undergo fission. This barrier may also be defined as the minimum amount of energy required to deform the nucleus to the point where it is irretrievably committed to the fission process. The energy to overcome this barrier can come from either neutron bombardment of the nucleus, where the additional energy from the neutron brings the nucleus to an excited state and undergoes deformation, or through spontaneous fission, where the nucleus is already in an excited and deformed state.

It is important to note that efforts to understand the fission process is still an ongoing activity and has been a very difficult problem to solve since its discovery by Otto Hahn and Fritz Strassmann in 1938. While nuclear physicists understand many aspects of the fission process, there is currently no encompassing theoretical framework that gives a satisfactory account of the basic observations.

Georg Puppe

Georg Puppe (1867–1925) was a German social physician and medical examiner.

Göttingen Eighteen

The Göttingen Eighteen (German: Göttinger Achtzehn) was a group of eighteen leading nuclear researchers of the newly founded Federal Republic of Germany who wrote the Göttingen Manifesto on April 12, 1957, opposing Chancellor Konrad Adenauer and Defense Secretary Franz-Josef Strauß's move to arm the West German army, the Bundeswehr, with tactical nuclear weapons.

The eighteen atomic scientists were: Fritz Bopp, Max Born, Rudolf Fleischmann, Walther Gerlach, Otto Hahn, Otto Haxel, Werner Heisenberg, Hans Kopfermann, Max von Laue, Heinz Maier-Leibnitz, Josef Mattauch, Friedrich Adolf Paneth, Wolfgang Paul, Wolfgang Riezler, Fritz Straßmann, Wilhelm Walcher, Carl Friedrich von Weizsäcker and Karl Wirtz.

These eighteen people were leading researchers and members of public institutions for research on nuclear energy and technology in West Germany in that time.

The group's name was chosen because many of the signatories were connected with the university town of Göttingen, and as a reference to the 19th century Göttingen Seven.

Göttingen Manifesto

The Göttingen Manifesto was a declaration of 18 leading nuclear scientists of West Germany (among them the Nobel laureates Otto Hahn, Max Born, Werner Heisenberg and Max von Laue) against arming the West German army with tactical nuclear weapons in the 1950s, the early part of the Cold War, as the West German government under chancellor Adenauer had suggested.

Kernphysikalische Forschungsberichte

Kernphysikalische Forschungsberichte (Research Reports in Nuclear Physics) was an internal publication of the German Uranverein, which was initiated under the Heereswaffenamt (Army Ordnance Office) in 1939; in 1942, supervision of the Uranverein was turned over to the Reichsforschungsrat under the Reichserziehungsministerium. Reports in this publication were classified Top Secret, they had very limited distribution, and the authors were not allowed to keep copies. The reports were confiscated under the Allied Operation Alsos and sent to the United States Atomic Energy Commission for evaluation. In 1971, the reports were declassified and returned to Germany. Many of the reports are available at the Karlsruhe Nuclear Research Center and the Niels Bohr Library of the American Institute of Physics. Many of them are reprinted and transcribed in the book

"Collected Works / Gesammelte Werke" listed below which is available in most libraries. There are reports numbered G-1 to G-395.Prominent German scientists who published reports in Kernphysikalische Forschungsberichte as members of the Uranverein can be grouped as follows:

Nine of the ten German nuclear physicists, except for Max von Laue, incarcerated in England at the close of World War II under Operation Epsilon: Erich Bagge, Kurt Diebner, Walther Gerlach, Otto Hahn, Paul Harteck, Werner Heisenberg, Horst Korsching, Carl Friedrich von Weizsäcker, and Karl Wirtz.

German physicists sent to Russia to work on the Soviet atomic bomb project: Robert Döpel, Walter Herrmann, Heinz Pose, Nikolaus Riehl, and Karl Zimmer.

Others: Fritz Bopp, Walther Bothe, Wolfgang Finkelnburg, Siegfried Flügge, Hans Geiger, Karl-Heinz Höcker, Fritz Houtermans, Georg Joos, Horst Korsching, Carl Ramsauer, Fritz Sauter, and Fritz Strassmann.

Lise Meitner

Lise Meitner (; German: [ˈmaɪtnɐ]; 7 November 1878 – 27 October 1968) was an Austrian-Swedish physicist who worked on radioactivity and nuclear physics. Meitner, Otto Hahn and Otto Robert Frisch led the small group of scientists who first discovered nuclear fission of uranium when it absorbed an extra neutron; the results were published in early 1939. Meitner, Hahn and Frisch understood that the fission process, which splits the atomic nucleus of uranium into two smaller nuclei, must be accompanied by an enormous release of energy. Nuclear fission is the process exploited by nuclear reactors to generate heat and, subsequently, electricity. This process is also one of the basics of nuclear weapons that were developed in the U.S. during World War II and used against Japan in 1945.

Meitner spent most of her scientific career in Berlin, Germany, where she was a physics professor and a department head at the Kaiser Wilhelm Institute; she was the first woman to become a full professor of physics in Germany. She lost these positions in the 1930s because of the anti-Jewish Nuremberg Laws of Nazi Germany, and in 1938 she fled to Sweden, where she lived for many years, ultimately becoming a Swedish citizen.

Meitner received many awards and honors late in her life, but she and Otto Frisch, did not share in the 1944 Nobel Prize in Chemistry for nuclear fission that was awarded exclusively to her long-time collaborator Otto Hahn. In the 1990s, the records of the committee that decided on that prize were opened. Based on this information, several scientists and journalists have called her exclusion "unjust", and Meitner has received many posthumous honors, including naming chemical element 109 meitnerium in 1992. Despite not having been awarded the Nobel Prize, Lise Meitner was invited to attend the Lindau Nobel Laureate Meeting in 1962.

List of experiments

See also: timeline of scientific experiments and List of discoveriesThe following is a list of historically important scientific experiments and observations demonstrating something of great scientific interest, typically in an elegant or clever manner.

Max Planck Institute for Chemistry

The Max Planck Institute for Chemistry (Otto Hahn Institute) (German: Max Planck Institut für Chemie - Otto Hahn Institut) is a non-university research institute under the auspices of the Max Planck Society (German: Max-Planck-Gesellschaft). It is based in Mainz.

In 2016 research at the Max Planck Institute for Chemistry in Mainz aims at an integral understanding of chemical processes in the Earth system, particularly in the atmosphere and biosphere. Investigations address a wide range of interactions between air, water, soil, life and climate in the course of Earth history up to today´s human-driven epoch, the Anthropocene. The Institute consists of five scientific departments (Atmospheric Chemistry, Climate Geochemistry, Biogeochemistry, Multiphase Chemistry, and Particle Chemistry) and additional research groups. The departments are independently led by their Directors.

Nuclear fission

In nuclear physics and nuclear chemistry, nuclear fission is a nuclear reaction or a radioactive decay process in which the nucleus of an atom splits into smaller nuclei(lighter nuclei). The fission process often produces free neutrons and gamma photons, and releases a very large amount of energy even by the energetic standards of radioactive decay.

Nuclear fission of heavy elements was discovered on December 17, 1938 by German Otto Hahn and his assistant Fritz Strassmann, and explained theoretically in January 1939 by Lise Meitner and her nephew Otto Robert Frisch. Frisch named the process by analogy with biological fission of living cells. For heavy nuclides, it is an exothermic reaction which can release large amounts of energy both as electromagnetic radiation and as kinetic energy of the fragments (heating the bulk material where fission takes place). In order for fission to produce energy, the total binding energy of the resulting elements must be more negative (greater binding energy) than that of the starting element.

Fission is a form of nuclear transmutation because the resulting fragments are not the same element as the original atom. The two nuclei produced are most often of comparable but slightly different sizes, typically with a mass ratio of products of about 3 to 2, for common fissile isotopes. Most fissions are binary fissions (producing two charged fragments), but occasionally (2 to 4 times per 1000 events), three positively charged fragments are produced, in a ternary fission. The smallest of these fragments in ternary processes ranges in size from a proton to an argon nucleus.

Apart from fission induced by a neutron, harnessed and exploited by humans, a natural form of spontaneous radioactive decay (not requiring a neutron) is also referred to as fission, and occurs especially in very high-mass-number isotopes. Spontaneous fission was discovered in 1940 by Flyorov, Petrzhak and Kurchatov in Moscow, when they decided to confirm that, without bombardment by neutrons, the fission rate of uranium was indeed negligible, as predicted by Niels Bohr; it was not.The unpredictable composition of the products (which vary in a broad probabilistic and somewhat chaotic manner) distinguishes fission from purely quantum-tunneling processes such as proton emission, alpha decay, and cluster decay, which give the same products each time. Nuclear fission produces energy for nuclear power and drives the explosion of nuclear weapons. Both uses are possible because certain substances called nuclear fuels undergo fission when struck by fission neutrons, and in turn emit neutrons when they break apart. This makes a self-sustaining nuclear chain reaction possible, releasing energy at a controlled rate in a nuclear reactor or at a very rapid, uncontrolled rate in a nuclear weapon.

The amount of free energy contained in nuclear fuel is millions of times the amount of free energy contained in a similar mass of chemical fuel such as gasoline, making nuclear fission a very dense source of energy. The products of nuclear fission, however, are on average far more radioactive than the heavy elements which are normally fissioned as fuel, and remain so for significant amounts of time, giving rise to a nuclear waste problem. Concerns over nuclear waste accumulation and over the destructive potential of nuclear weapons are a counterbalance to the peaceful desire to use fission as an energy source.

Otto Hahn

Otto Hahn (8 March 1879 – 28 July 1968) was a German chemist and pioneer in the fields of radioactivity and radiochemistry. Otto Hahn discovered nuclear fission in 1938. He is referred to as the father of nuclear chemistry. He was awarded the Nobel Prize in Chemistry in 1944 for the discovery and the radiochemical proof of nuclear fission. This process is exploited by nuclear reactors and is one of the basics of nuclear weapons that were developed in the U.S. during World War II.

He served as the last President of the Kaiser Wilhelm Society (KWG) in 1946 and as the founding President of the Max Planck Society (MPG) from 1948 to 1960. Considered by many to be a model for scholarly excellence and personal integrity, he became one of the most influential and respected citizens of the new postwar country West Germany.

Hahn was an opponent of national socialism and Jewish persecution by the Nazi Party. Albert Einstein wrote that Hahn was "one of the very few who stood upright and did the best he could in these years of evil". After World War II, Hahn became a passionate campaigner against the use of nuclear energy as a weapon.

Otto Hahn Peace Medal

The Otto Hahn Peace Medal in Gold is named after the German nuclear chemist and 1944 Nobel Laureate Otto Hahn, an honorary citizen of Berlin.

The medal is in memory of his worldwide involvement in the politics of peace and humanitarian causes, in particular since the dropping of the atomic bombs on Hiroshima and Nagasaki in August 1945 by the United States Army Air Forces.

It was established by his grandson Dietrich Hahn in 1988 and is awarded by the United Nations Association of Germany (Deutsche Gesellschaft für die Vereinten Nationen, DGVN, Berlin-Brandenburg) to persons or institutions that have rendered "outstanding services to peace and international understanding". By tradition, the gold medal, together with a leather-bound diploma inlaid in gold, is presented in Berlin at a biennial ceremony on 17 December by the Governing Mayor of Berlin and the President of the DGVN.

On 17 December 1938, in Berlin-Dahlem, Otto Hahn and his assistant Fritz Strassmann had discovered a new reaction in uranium (which exiled Lise Meitner and her nephew Otto Frisch two weeks later correctly interpreted as "nuclear fission") thus laying the scientific and technical foundations of nuclear energy. This 17 December 1938 therefore marks the beginning of the Atomic age, which from the scientific, political, economic, social and philosophical point of view has fundamentally changed the world.

Reinhold Strassmann

Reinhold Strassmann (or Straßmann) (24 January 1893 in Berlin – late October 1944 in Auschwitz concentration camp) was a German mathematician who proved Strassmann's theorem. His Ph.D. advisor at University of Marburg was Kurt Hensel.

Born into a Jewish family, Strassmann refused to leave Nazi Germany, and he was eventually detained and deported to Theresienstadt concentration camp in 1943. On October 23, 1944, he was deported from Theresienstadt to Auschwitz concentration camp, where he was murdered soon after.He was the son of the forensic pathologist Fritz Strassmann.

Rubidium–strontium dating

The rubidium-strontium dating method is a radiometric dating technique used by scientists to determine the age of rocks and minerals from the quantities they contain of specific isotopes of rubidium (87Rb) and strontium (87Sr, 86Sr).

Development of this process was aided by German chemists Otto Hahn and Fritz Strassmann, who later went on to discover nuclear fission in December 1938.

The utility of the rubidium–strontium isotope system results from the fact that 87Rb (one of two naturally occurring isotopes of rubidium) decays to 87Sr with a half-life of 49.23 billion years. In addition, Rb is a highly incompatible element that, during partial melting of the mantle, prefers to join the magmatic melt rather than remain in mantle minerals. As a result, Rb is enriched in crustal rocks. The radiogenic daughter, 87Sr, is produced in this decay process and was produced in rounds of stellar nucleosynthesis predating the creation of the Solar System.

Different minerals in a given geologic setting can acquire distinctly different ratios of radiogenic strontium-87 to naturally occurring strontium-86 (87Sr/86Sr) through time; and their age can be calculated by measuring the 87Sr/86Sr in a mass spectrometer, knowing the amount of 87Sr present when the rock or mineral formed, and calculating the amount of 87Rb from a measurement of the Rb present and knowledge of the 85Rb/87Rb weight ratio.

If these minerals crystallized from the same silicic melt, each mineral had the same initial 87Sr/86Sr as the parent melt. However, because Rb substitutes for K in minerals and these minerals have different K/Ca ratios, the minerals will have had different Rb/Sr ratios.

During fractional crystallization, Sr tends to become concentrated in plagioclase, leaving Rb in the liquid phase. Hence, the Rb/Sr ratio in residual magma may increase over time, resulting in rocks with increasing Rb/Sr ratios with increasing differentiation.

Highest ratios (10 or higher) occur in pegmatites.

Typically, Rb/Sr increases in the order plagioclase, hornblende, K-feldspar, biotite, muscovite. Therefore, given sufficient time for significant production (ingrowth) of radiogenic 87Sr, measured 87Sr/86Sr values will be different in the minerals, increasing in the same order.


Strassman may refer to:

Karen Strassman, American voice actress

David Strassman, American ventriloquist

Marcia Strassman, American actress

Rick Strassman, American psychedelic researcher

Toni Strassman, American literary agent

Harvey D. Strassman, American psychiatrist

Todd Strassman, bass player for the band What Is This?See alsoFritz Strassmann, German chemist

19136 Strassmann, asteroid

Strassmann's theorem


Strassmann is a German surname. Notable people with the surname include:

Antonie Strassmann, German stage actress and aviator

Diana Strassmann, American economist

Fritz Strassmann, German chemist

19136 Strassmann asteroid

Joan E. Strassmann Biologist

Reinhold Strassmann, German mathematician

Strassmann's theorem

Wolfgang Straßmann, German politician

Terrestrial Physics

Terrestrial Physics is a sculpture by American artist Jim Sanborn which includes a full-scale working particle accelerator. It was displayed in the Museum of Contemporary Art as part of Denver's Biennial of the Americas from June–September 2010.

Walter Seelmann-Eggebert

Wilhem Walter Rudolph Max Seelmann-Eggebert (17 April 1915 – 19 July 1988) was a German radiochemist. He was son of Erich Eggebert and Edwig Schmidt.

He was a student of Otto Hahn at the Kaiser Wilhelm Institute for Chemistry, where, after 1939, he worked with Fritz Strassmann on nuclear fission.

In 1949, he joined the University of Tucuman in Argentina as a professor of chemistry. Later he created the radiochemistry group at the Buenos Aires University and at the National Atomic Energy Commission, working together with other notable pioneers of radiochemistry, such as Sara Abecasis, Gregorio Baro, Juan Flegenheimer, Jaime Pahissa-Campá, María Cristina Palcos, Enzo Ricci, Renato Radicella, Plinio Rey, Josefina Rodríguez, and Maela Viirsoo, just to mention a few. During his Argentinian years his group discovered 20 new nuclides.

In 1955, Otto Hahn invited him to come back to Germany for the reconstruction of radiochemistry studies in the country. He became professor in Mainz before creating and managing the Radiochemistry Institute from the Karlsruhe Kernforschungszentrum, now the Karlsruhe Institute of Technology (KIT).

In 1958, together with Gerda Pfennig, he edited the first "Karlsruher Nuklidkarte" which has become a basic element both for nuclear scientists and education.

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