Niels Bohr
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Biography
Niels Bohr was a Danish physicist who lived from 1885 to 1962. He is famous for his contributions to atomic and quantum physics; these contributions were significant enough to earn himself a Nobel Prize in Physics in 1922. He is most well known for his contributions to the Manhattan Project to develop the first atomic bomb. He is widely regarded as one of the most influential physicists of the 20th century.

Niels Bohr was born on October 7, 1885 in Copenhagen, Denmark. His father was Christian Bohr and his mother was Ellen Adler Bohr. Christian Bohr was a professor of physiology at the University of Copenhagen. His mother Ellen came from a wealthy Jewish banking family. Bohr grew up in a positive educational environment that fostered the development of his genius. He grew up in Copenhagen and enrolled in the University of Copenhagen in 1903, planning to study philosophy and mathematics. He soon switched his focus to physics. In 1909 he received his Master’s Degree in Physics and in 1911 he received his Doctor’s Degree.

In 1911 Bohr went to live in Cambridge, England where he was exposed to such scientific genius as Sir J.J. Thomson, and where he was given the chance to continue to pursue his theoretical studies. In the spring of 1912 he worked with Ernest Rutherford at Manchester University. Basing much of his theories on Rutherford’s existing work, Bohr published his model of atomic structure in 1913, providing an enormous contribution to the field of atomic physics. He was awarded with a Nobel Prize in Physics in 1922 for his work.

In 1916 Bohr became a professor at the University of Copenhagen and founded and became the director of the Institute of Theoretical Physics at the university in 1921. His winning of the Nobel Prize the following year attracted significant attention from the great physicists of the time and many of the most brilliant physicists of the world spent time at Bohr’s institute.

On the outbreak of World War II, Bohr was opposed to the Nazi regime and was active in helping Jewish victims, especially physicists, actions for which the Germans took notice. In 1943 Bohr was forced to flee Europe and eventually made his way to the United States to work on the top secret Manhattan Project to develop an atomic bomb. The exact records of his individual contributions to the project remain sealed, though it is likely that he held some sort of leadership position among the physicists working on it. After the war ended he became an activist for the peaceful, rather than military, application of atomic energy.
Niels Bohr died of heart failure in Copenhagen in 1962.
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What is Niels Bohr Well Known For?
Throughout his life and scientific career, Niels Bohr made numerous contributions to the field of physics. As early as 1913 he was already publishing new findings based on his own theoretical studies. In that year Bohr published what would become known as the Bohr model, a physics concepts that says that electrons travel in discrete orbits around the atom’s nucleus. Bohr developed his theory after working with Ernest Rutherford and his model is based upon and expanded off of much of Rutherford’s work. Bohr’s publication of his atomic model was so groundbreaking and significant to the scientific community that his work earned himself a Nobel Prize in Physics in 1922. The idea of electron configuration also stemmed off of Bohr’s work on the Bohr model. Bohr also developed something called the correspondence principal in 1920. Bohr worked with an American physicist named John Archibald Wheeler to develop the liquid drop model, which describes the nucleus of an atom as a drop of incompressible nuclear fluid. Bohr also worked on other physics concepts such as the Copenhagen interpretation of quantum mechanics and the complementarily principle.

Although Bohr’s largest single contribution to the scientific community was his publication of the Bohr model, he also took part in the single most important scientific undertaking of the 20th century: the Manhattan Project. Niels Bohr’s individual contributions involved uranium-235 and the efforts to separate that fissionable isotope from the more plentiful but non-fissionable uranium-238. It is likely that he held some sort of senior position on the team that was meant to research this aspect of the atomic bomb project. Despite his participation in the project, Bohr remained conflicted about his work. He recognized the awesome destructive power of the atomic bomb and the potentially catastrophic consequences its creation would cause. At the same time, he saw the enormous potential of nuclear energy and advocated for its peaceful application.
Relevance to the Atomic Bomb
Niels Bohr’s participation in the Manhattan Project means that he has direct relevance to the atomic bomb. His work with uranium-235 and uranium-238 was instrumental in the acquisition of the fissionable material needed to give the atomic bomb its destructive power. While there is no evidence to suggest that Bohr was one of the leading members of the Manhattan Project, it is probable that Bohr held at least some form of senior position on the team assigned to work with the isotope separation of uranium-235 and uranium-238.

Despite the fact that the Manhattan Project was designed to create a weapon of mass destruction, Bohr held a very passive opinion about the applications of his work. He believed that nuclear energy had enormous peaceful applications, and was visibly opposed to the use of atomic energy as a weapon. For example, he proposed the sharing of scientific knowledge with Russian physicists because he believed research should be shared with the entire global scientific community. This idea was met with staunch resistance due to political reasons; the Cold War was about to begin and relations between the United States and the Soviet Union were breaking down. Politics were getting in the way of scientific process, a fact that Bohr didn’t like.

After the war, Bohr continued to advocate for the peaceful use of nuclear energy until his death in 1962.

Sources:
http://en.wikipedia.org/wiki/Niels_Bohr
http://en.wikipedia.org/wiki/Manhattan_Project#Uranium
http://upload.wikimedia.org/wikipedia/commons/d/d5/Niels_Bohr_Albert_Einstein_by_Ehrenfest.jpg
http://nobelprize.org/nobel_prizes/physics/laureates/1922/bohr-bio.html
http://www.doug-long.com/bohr.htm
http://www.famous-scientists.net/niels-bohr.htm