BOHR, NIELS (HENRIK DAVID)

born Oct. 7, 1885, Copenhagen, Den. died Nov. 18, 1962, Copenhagen Danish physicist and Nobel laureate, the major contributor to the development of quantum physics for almost 50 years. He is responsible for the Bohr theory of the atom and liquid-drop model of the atomic nucleus. Bohr, son of Christian Bohr, a professor of physiology at the University of Copenhagen, showed an interest and talent in the physical sciences early in life. At the age of 22 he won a gold medal from the Danish Scientific Society for his determination of the surface tension of water. He received a doctorate in physics from the University of Copenhagen in 1911 for a thesis on the electron theory of metals. He then went to England and worked at the University of Cambridge under J.J. Thomson and subsequently at Victoria University of Manchester with E. Rutherford's group studying the structure of the atom. Bohr stayed on at Manchester, with some interruptions, until 1916 and served on the university faculty for two years. He returned to Copenhagen in 1916 as professor and in 1920 became director of the newly created Institute of Theoretical Physics, a position he held until his death. He was awarded the Nobel Prize for Physics in 1922. When Denmark was occupied by the Germans in 1940, Bohr took an active part in the anti-Nazi resistance movement. In 1943, under threat of immediate arrest, he escaped to Sweden with his family by fishing boat. Although he participated in the atomic bomb project at Los Alamos, N.M., as early as 1944 his concern about such awesome weapons was clear. He was convinced that free exchange of people and ideas among countries was necessary to achieve control of nuclear weapons. Bohr received the first Atoms for Peace Award in 1957. Bohr's works include The Theory of Spectra and Atomic Constitution (1922), Atomic Theory and the Description of Nature (1934), and Atomic Physics and Human Knowledge (1958). The last mentioned contains Bohr's account of his discussions with Albert Einstein on quantum theory over two decades.