BOHR, NIELS HENRIK DAVID

BOHR, NIELS HENRIK DAVID (1885–1962), Danish physicist and Nobel laureate. He was born in Copenhagen. His father was non-Jewish, a professor of physiology at the University of Copenhagen, and his mother, née Ella Adler, belonged to a prominent Jewish banking family. He obtained his doctorate at Copenhagen in 1911 with a thesis on "Investigations of Metals." In 1912, he worked with J.J. Thomson (the discoverer of the electron) at Cambridge, and then in Manchester with Ernest Rutherford, the discoverer of the atomic nucleus. In 1913, Bohr produced the first of his series of papers which revolutionized conceptions of the structure of the atom. In 1916, Bohr became professor of chemical physics at the University of Copenhagen, and in 1920 head of the university's new Institute of Theoretical Physics. He participated in other important advances, such as the "Correspondence Principle" and the "Principle of Complementarity." In 1922, he was awarded the Nobel Prize, the youngest laureate up to that time. He helped to lead science through the most fundamental change of attitude it has made since Galileo and Newton. In September 1943 he and his family escaped the Nazis by going to Sweden in a fishing boat. In October he was taken to England in the bomb rack of an unarmed Mosquito plane. Bohr was "consultant" to Tube Alloys, the code name for the atomic bomb project. He had determined that the uranium atom which had been split by Hahn and Strassman in 1938 was the rare isotope U-235, a fact of major importance to the project. However, Bohr saw the atom bomb as a threat to mankind. He was given the first Atoms-for-Peace prize of the Ford Foundation in 1956 and was chairman of the Danish Atomic Energy Commission. In the last fifteen years of his life, he was tireless in his work for peace. He took an active interest in the physics program of the Weizmann Institute of Science at Reḥovot which he visited on several occasions. -BIBLIOGRAPHY: W. Pauli (ed.), Niels Bohr and the Development of Physics (1955); S. Rozental (ed.), Niels Bohr; his Life and Work… (1967); R.E. Moore, Niels Bohr: the Man, his Science and the World they Changed (1966). (Samuel Aaron Miller)