Niels Bohr

Niels Henrik David Bohr (October 7, 1885 – November 18, 1962) was a Danish physicist who made essential contributions to understanding atomic structure and quantum mechanics.

Biography

Early years

Bohr was born in Copenhagen in 1885. His father, Christian Bohr, was a professor of physiology at the University of Copenhagen, while his mother, Ellen Adler Bohr, came from a wealthy Sephardic Jewish family prominent in Danish banking and parliamentary circles. His brother was Harald Bohr, a mathematician and Olympic soccer player.

Related Topics:
Copenhagen - 1885 - Christian Bohr - Ellen Adler Bohr - Sephardic - Harald Bohr - Mathematician - Olympic - Soccer

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Bohr received his doctorate from Copenhagen University in 1911. He then studied under Ernest Rutherford in the Victoria University of Manchester in England. Based on Rutherford's theories, Bohr published his model of atomic structure in 1913, introducing the theory of electrons travelling in orbits around the atom's nucleus, the chemical properties of the element being largely determined by the number of electrons in the outer orbits. Bohr also introduced the idea that an electron could drop from a higher-energy orbit to a lower one, emitting a photon (light quantum) of discrete energy. This became a basis for quantum theory.

Related Topics:
Copenhagen University - 1911 - Ernest Rutherford - Victoria University of Manchester - England - Model - 1913 - Electron - Orbit - Nucleus - Photon - Quantum - Quantum theory

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Middle years

In 1916, Niels Bohr became a professor at the University of Copenhagen, and director of the newly constructed "Institute of Theoretical Physics" in 1920. In 1922, he was awarded the Nobel Prize in physics "for his services in the investigation of the structure of atoms and of the radiation emanating from them".

Related Topics:
1916 - 1920 - 1922 - Nobel Prize - Physics

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Bohr also conceived the principle of complementarity: that items could be separately analyzed as having several contradictory properties. For example, physicists currently conclude that light is both a wave and a stream of particles - two apparently mutually exclusive properties - based on this principle. Bohr also found philosophical applications for this daringly original principle. Albert Einstein much preferred the determinism of classical physics over the probabilistic new physics of Bohr (to which Max Planck and Einstein himself had contributed). He and Bohr had good-natured arguments over the verity of this principle throughout their lives. One of Bohr's most famous students was Werner Heisenberg, a crucial figure in the development of quantum mechanics, who was also head of the German atomic bomb project.

Related Topics:
Complementarity - Albert Einstein - Max Planck - Werner Heisenberg

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Niels Bohr and his wife Margrethe had six children. Two died young, and most of the others went on to lead successful lives. One, Aage Niels Bohr, also became a very successful physicist; like his father, he won a Nobel prize.

Related Topics:
Aage Niels Bohr - Nobel prize

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Later years, death, and legacy

In 1941, during the German occupation of Denmark in World War II, Bohr was visited by Heisenberg in Copenhagen (see next section). In 1943, shortly before he was to be arrested by the German police, Bohr escaped to Sweden, and then travelled to London.

Related Topics:
1941 - German - World War II - 1943 - Sweden - London

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He worked at the secret Los Alamos laboratory in New Mexico, USA, on the Manhattan Project, where, according to Richard Feynman, he was known by the assumed name of Nicholas Baker for security reasons. However his role in the project was minor. He is quoted as saying "That is why I went to America. They didn't need my help in making the atom bomb." He was seen as a knowledgeable consultant or "father confessor" on the project http://www.doug-long.com/bohr.htm.

Related Topics:
Los Alamos - New Mexico - USA - Manhattan Project - Richard Feynman

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Bohr believed atomic secrets should be shared by the international scientific community. After meeting with Bohr, J. Robert Oppenheimer suggested Bohr visit President Franklin Roosevelt to convince him that the Manhattan Project should be shared with the Russians in the hope of speeding up its results. Roosevelt suggested Bohr return to England to try to win British approval. Churchill opposed the idea.{{NamedRef|Rhodes1|1}}

Related Topics:
J. Robert Oppenheimer - President Franklin Roosevelt - Churchill

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After the war he returned to Copenhagen, advocating the peaceful use of nuclear energy. He died in Copenhagen in 1962. He is buried in the Assistens Kirkegård in the Nørrebro section of Copenhagen.

Related Topics:
Nuclear energy - Assistens Kirkegård - Nørrebro

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The element bohrium is named in his honor.

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