Niels Bohr

Definition: Niels Bohr

Niels Bohr

Noun

1. Danish physicist who studied atomic structure and radiations; the Bohr theory of the atom accounted for the spectrum of hydrogen (1885-1962).

Synonyms: Niels Bohr

Synonyms: Bohr (n), Niels Henrik David Bohr (n). (additional references)

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

Born in Copenhagen, Denmark to Christian Bohr and Ellen Adler, Bohr got his doctorate at Copenhagen University in 1911. He then studied under Ernest Rutherford in Manchester, England. Based on Rutherford's theories, Bohr published his Bohr model about atom structure in 1913, introducing the theory of electrons travelling on orbits around the atom's nucleus, with the outer orbits holding more electrons than the inner ones, thereby determining the chemical properties of the atom. Also, an electron could drop from an outer orbit to an inner one, emitting a photon (light) of discrete energy. This became the basis for quantum theory.

In 1916, Bohr became 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 developing the Copenhagen interpretation of quantum mechanics.

Bohr also conceived the principle of complimentarity: 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 seemingly mutually exclusive properties--based on this principle. Bohr also found philosophical applications for this daringly original principle. Albert Einstein much preferred the clarity of classical physics over the new physics of Bohr and Max Planck. 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, who became head of the German atomic bomb project. In 1941, during the German occupation of Denmark in World War II, Bohr was visted by Heisenberg in Copenhagen and apparently learned something of the German plans. In 1943 he escaped to Sweden to avoid arrest by the German police, then travelled to London. He worked at Los Alamos, New Mexico, USA, on the Manhattan Project, however his role 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 knowledgable consultant or "father confessor" on the project [1]. After the war he returned to Copenhagen, advocating for a peaceful use of nuclear energy. He died in Copenhagen.

On the relation to Heisenberg

Heisenberg claimed in an interview after the war when the author Robert Jungk was working with the book Brighter than a thousand suns, that he had tried to establish a pact with Bohr, so that scientists on neither side should help develop the atomic bomb. He also said that the German attempts were entirely focused on energy production, and that his circle of colleagues tried to keep it that way.

When Bohr saw this claim he disagreed wholeheartedly. He said, that Heisenberg had indeed let him know in Copenhagen that he was working on an atomic bomb project, and that he thought that Germany would win the war. He dismissed the idea of any pact as an after-the-fact construction. He drafted several letters to inform Heisenberg about this but never sent any of them.

The play Copenhagen, which ran on Broadway for a time, written by Michael Frayn, was about what might have happened at the 1941 meeting between Heisenberg and Bohr.

The element Bohrium is named in his honor.

Books about Bohr

Niels Bohr : The Man, His Science, and the World They Changed by Ruth Moore ISBN 0262631016

External link

Crosswords: Niels Bohr

English words defined with "Niels Bohr": Franck ♦ James Franck. (references)

Domain	Usage
Clever	Your theory is crazy--but not crazy enough to be true. (references; author: Niels Bohr) An expert is a man who has made all the mistakes, which can be made, in a very narrow field. (references; author: Niels Bohr)
Movie/TV Titles	Niels Bohr (1952)
Source: compiled by the editor from various references; see credits.

Domain	Title
Books	The Physics of Chance: From Blaise Pascal to Niels Bohr (reference) (more book examples)
Source: compiled by the editor from various references; see credits.

Thumbnail	Description & Credit
	Philip Bosco as physicist Niels Bohr in "Copenhagen" and Claudia Shear as Mae West in "Dirty Blonde" / Hirschfeld 5.Credit: Library of Congress.
Source: compiled by the editor from various references; see credits.

Author	Quotation
Niels Bohr	Your theory is crazy--but not crazy enough to be true.
	An expert is a man who has made all the mistakes, which can be made, in a very narrow field.
Source: compiled by the editor from various references.

Subject	Topic	Quote
Economic History	Denmark	The astronomical discoveries of Tycho Brahe (1546-1601) and the brilliant contributions to atomic physics of Niels Bohr (1885-1962) indicate the range of Danish scientific achievement. (references)
Source: compiled by the editor from ICON Group International, Inc.; see credits.

The following statistics estimate the number of searches per day across the major English-language search engines as identified by various trade publications. Hyperlinks lead to commercial use of the expression at Amazon.com.

Scrabble® Enable2K-Verified Anagrams
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	Words containing the letters "b-e-h-i-l-n-o-r-s"
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