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Otto Hahn

1879 - 1968

Otto Hahn, 1879 - 1968, German physicist

Otto Hahn, 1879 - 1968, was a German chemist, who was awarded the Nobel Prize for Chemistry in 1944 for his discovery of fission.

  • Nationality
  • German

  • Subject
  • Chemistry, Nuclear

  • Fields
  • Radioactivity, Radiochemistry, Nuclear fission

  • Distinctions
  • Nobel Prize in Chemistry, 1944, for the explanation of nuclear fission in Uranium as a radiochemical decay.

    Recipient of at least 12 other prestigious awards, including the Enrico Fermi Award (1966) and the L├Ęgion d'Honneur (1959).

  • Posts
  • PhD at University of Marburg in organic chemistry, 1901.

    University College London, 1904, under Sir William Ramsay (of Inert Gases Discovery fame), where he researched radiochemistry.

    McGill University, Montreal, Canada, with Rutherford, 1905-6, where he discovered a further 4 isotopes.

    University of Berlin, 1906, with Emil Fischer, and from 1907 - 1938, Lise Meitner.

    In 1912, he became the first director of the Radioactivity Department of the Kaiser Wilhelm Institute for Chemistry in Berlin-Dahlem (now 'Hahn-Meitner-Building' of the Free University, Berlin). Director 1928 - 1946.

    Hahn was the last president of the Kaiser Wilhelm Society (KWG) in 1946.

    Founding president of the Max Planck Society (MPG), 1948 - 1960.

  • Laws
  • Fajans-Paneth-Hahn Law

  • Theories
  • Explained radioactive recoil as alpha particle emission.

    Uranium fission, which started the modern nuclear energy (and weapons) industry.

  • Experiments/Discoveries
  • Hahn discovered the following radioactive elements and isotopes: Radiothorium (1905), Radioactinium (1906), Mesothorium (1907), Ionium (1907), Protactinium (1917).

    Radioactive recoil (1909)

    Nuclear isomerism (1921)

    Applied radiochemistry (1936)

    Rubidium-strontium dating (1938)

Otto Hahn and Lise Meitner
Otto Hahn and Lise Meitner, in their Laboratory, 1913

Working with Lise Meitner and Fritz Strassman, he discovered that uranium, the largest natural element, underwent radiochemical decay. As a result he is often lauded with the moniker 'the Father of nuclear Chemistry'.

Luckily for the world, Hahn was opposed to Naziism, and did not aid them in their attempt to build the atomic bomb, and after the war joined the movement of scientists opposed to the use of nuclear science for weapons.

Read about physics on
the 'Otto Hahn' atomic ship, 1964

After the fall of Germany, Hahn and several other German scientists were interned at Farm Hall, near Cambridge. Here he heard the news of the use of atomic weapons on Japan, and was devastated:

"Hahn had been first informed about Hiroshima on August 6, 1945, by the British officer in charge at Farm Hall. The news completely shattered him, for he felt that his discovery of fission had made construction of the atomic bomb possible, and that he was thus personally responsible for the thousands of deaths in Japan. Long before, he had contemplated suicide, when he first recognized the possible military use of fission; now, with the blame of its realization drawn squarely upon his shoulders, suicide again seemed a way to escape his desolation. Fearing this, Max von Laue remained with him until he passed this personal crisis. Never has social responsibility hit a scientist with such impact." Essay by Lawrence Badash, University of California.

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