NIELS BOHR By Maddie O’Connor

Early Life/Family Life Niels Henrik David Bohr was born on October 7, 1885 in Copenhagen, Denmark. His mother was a banker and his father was a physiology scholar. In 1912, Bohr married Margrethe Nørlund. She gave birth to six children and only four survived.

Schooling After completing his education at Gammelholm Grammar School in 1903, Bohr attended Copenhagen University where he came under the guidance of Professor C. Christiansen, a renowned physicist, and earned his master's degree in Physics in 1909 and his doctoral degree in 1911. Following this, Bohr traveled to Cambridge, England, where he was able to observe the laboratory work of scientist J.J. Thomson.

Field of Study During his last few years at Copenhagen University, Bohr began to specialize in physics and mathematics. Bohr mainly focused on physics with mathematics, astronomy, and chemistry being his minor studies.

Inspiration Bohr was largely inspired by his father, a physician. It was his father, more than his school teachers, who inspired him in his studies. In 1922, Bohr wrote: “My interest in the study of physics was awakened while I was still in school, largely owing to the influence of my father.”

Bohr Atomic Model Bohr’s first contribution to the emerging new idea of quantum physics started in 1912. One year prior, Rutherford and his collaborators had established experimentally that the atom consists of a heavy positively charged nucleus with lighter negatively charged electrons circling around it at considerable distance. According to classical physics, such a system would be unstable, and Bohr wanted to prove that electrons could only occupy particular orbits determined by the quantum of action and that electromagnetic radiation from an atom occurred only when an electron jumped to a lower-energy orbit. Although radical and unacceptable to most physicists at the time, the Bohr atomic model was able to account for an increasing number of experimental data.

Bohr’s Institute for Theoretical Physics In the spring of 1916, Bohr was offered a new professorship at the University of Copenhagen; dedicated to theoretical physics. In the spring of 1917 Bohr wrote a long letter to his faculty asking for the establishment of an Institute for Theoretical Physics. In the inauguration speech for his new institute on March 3, 1921, he expressed his ambition to make the new institute a place where the younger generation of physicists could put forth fresh ideas.

Nobel Prize/Other Work In 1922, Bohr was awarded a Nobel Prize for his “services in the investigation of the structure of atoms and of the radiation emanating from them.” After this, Bohr sought to apply his atomic theory to the understanding of the periodic table of elements. Hungarian physical chemist Georg Hevesy, together with the physicist Dirk Coster from Holland, were working at Bohr’s institute to establish experimentally that the atomic element 72 would behave as predicted by Bohr’s theory. They succeeded in 1923, proving the strength of Bohr’s theory.

Splitting the Atom German physicists Otto Hahn and Fritz Strassmann in 1938 had made the unexpected experimental discovery that a uranium atom can be split in two approximately equal halves when bombarded with neutrons, a theoretical explanation based on Bohr’s theory of the compound nucleus. By that time, at the beginning of 1939, Bohr was in the United States, where a race to confirm experimentally the fission of the nucleus began after the news of the German experiments and their explanation had become known. In the United States, Bohr did innovative work at Princeton University to explain fission theoretically.

Death After having a stroke, Bohr died on November 18, 1962 in Copenhagen, Denmark.

Works Cited http://www.pbs.org/wgbh/aso/databank/entries/bpbohr.html http://www.nobelprize.org/nobel_prizes/physics/laureates/1922/bohr-bio.html http://www.biography.com/people/niels-bohr-21010897#fleeing-europe https://www.britannica.com/biography/Niels-Bohr