Hahn, Otto (1879-1968), a German physical chemist. In 1938 Hahn and Fritz Strassmann split nuclei of uranium atoms into roughly equal segments. This experiment was the first demonstration of nuclear fission and indicated that the manufacture of an atomic bomb was possible. Hahn was awarded the 1944 Nobel Prize in chemistry and shared the 1966 Fermi Award for his work on nuclear fission.
Hahn received his Ph.D. from the University of Marburg in 1901. He discovered several radioactive substances while working under Sir William Ramsay in England. 1904-05, and under Ernest Rutherford in Canada, 1905-06. Hahn joined the Kaiser Wilhelm Institute for Chemistry at Berlin in 1912 and became director in 1928. In 1917, working with Lise Meitner at the institute, he discovered the element protactinium. (Two English scientists discovered this element independently of Hahn and Meitner at about the same time.)
With the fall of Germany in World War II, Hahn and other leading German atomic scientists were held in England by the Allies. Returning to Germany in early 1946, Hahn became president of the country's main scientific research organization, the Max Planck Society. He was honorary president of the society after 1960.
Among his books is Otto Hahn: a Scientific Autobiography (1962, English translation 1966).