Niels Bohr (1885-1962), a Danish physicist, is noted for his work with radiation and atomic theory. In 1922 he was awarded the Nobel Prize for Physics, and in 1957 he received the first Atoms for Peace Award of the Ford Foundation.
Bohr was born in Copenhagen, Denmark. After graduation from the University of Copenhagen, he went to England in 1911. At Ernest Rutherford’s laboratory in Manchester he began developing his theory of atomic structure.
Using Rutherford’s model of the atom of hydrogen, the simplest element, Bohr helped to confirm the picture of the atom as consisting of a massive, positively charged nucleus orbited by negatively charged electrons. Bohr’s theory was that the electrons traveled in orbits that could only be of certain sizes. Bohr suggested that, when an electron moved from one orbit to another closer to the nucleus, it gave off energy in the form of light rays. The energy was given off in little “packets called quanta, and Bohr concluded that the sizes of electron orbits were governed by quantum numbers. In 1938 scientists discovered fission and opened the way to the release of nuclear energy. Bohr then proposed a theory to explain this process.
The quantum theory was new when Bohr began his work. It is now an important part of physics. Bohr showed that the quantum theory did not conflict with older theories as much as many scientists first believed.
Bohr was forced to leave Denmark during World War II. After spending some time in Sweden and England, he was made an adviser at the atomic laboratory at Los Alamos, New Mexico. In 1945, after the first atomic bomb had been dropped, he argued in Washington, DC, for international control of atomic weapons. He returned to Denmark the same year and became chairman of the Danish atomic energy commission. Later, he again became director of the Institute for Theoretical Physics.