FRISCH, OTTO ROBERT (1904–1979) physicist, nephew of the physicist Lise *Meitner. Frisch was born in Vienna but was naturalized as a British citizen (1943). After gaining his D.Phil. in physics from the University of Vienna (1926) he worked at the national physics laboratory in Berlin (1927–30) and with the Nobel physics laureate Otto *Stern in Hamburg (1930–33). With the coming of the Nazis, he left Germany in 1933 to work in Patrick Blackett's laboratory in Birkbeck College, London, before joining Niels *Bohr's laboratory in Copenhagen (1934–38). With the threat of war and invasion, Frisch moved to Mark Oliphant's laboratory in Birmingham, England (1939–40) but joined James Chadwick's laboratory in Liverpool as this was more appropriate for his work. With the merging of U.K. and U.S. research on nuclear weapons he moved to Los Alamos (1943–46), returning to England in 1946 as head of the nuclear physics division at the Atomic Energy Establishment in Harwell. In 1947 he was appointed Jacksonian Professor of natural philosophy at Cambridge University and a fellow of Trinity College, working in the Cavendish Laboratory. He retired in 1972. His initial research in Germany concerned the physical properties of nuclear particles, including the discovery of the magnetic moment of protons. In Copenhagen he studied radioactive isotopes and the outcome of collisions between neutrons and nuclei. At the end of 1938 he and Lise Meitner calculated the enormous energy which could potentially be released by what they termed "fission," the process just described by Otto Hahn and Fritz Strassman whereby uranium nuclei are split by colliding neutrons. He rapidly identified the fission products experimentally in Bohr's laboratory. Frisch was early to recognize the practical implications of sustained fission and, in collaboration with Rudolf Peierls, he calculated that neutrons could induce a chain reaction in a small enough quantity of pure uranium 235 to make a bomb feasible. In Los Alamos he worked in considerable personal danger on the chain reactions in pure uranium 235 and plutonium underlying the first fission bombs. In Cambridge he developed devices for tracking particles, one of which was marketed successfully under his chairmanship. He was also deeply interested in science education and he wrote many well received books for general readers. He continued his commercial and literary interests in retirement. He was elected a fellow of the Royal Society in 1948.

[Michael Denman (2nd ed.)]
