Niels bohr atomic theory and the des Continue Danish physicist Bohr redirects here. For other uses, see Bohr (deambiguation). Niels BohrBornNiels Henrik David Bohr (1885-10-07)October 7, 1885Copenhagen, DenmarkDied18 November 1962 (1962-11-18) (77 years)Copenhagen, DenmarkResting placeAssistens CemeteryAlma materUniversity of CopenhagenKnown for Physics contributions Bohr magnetonBohr modelBohr radiusBohr-Einstein debatesBohr-Kramers-Slater theory Bohr-van Leeuwen teorremBohr-Sommerfeld theoryComplementarity Complementarity Wife(s)Margrethe Nørlund (m. 1912)ChildrenAage, Ernest, four other sons Nobel Prize in Physics (1922) plus praise shughes medal (1921)Matteucci Medal (1923)Franklin Medal (1926) Foreign Member of the Royal Society (1926)Max Planck Medal (1930) Faradaylectureship Prize (1930) Copley Medal (1938)Order of the Elephant (1947) Atoms for Peace Award (1957)Sonning Prize (1957) Scientific careerFieldsTheoretical physicsInstitutionsTrinity College, CambridgeUniversity university of CopenhagenVictoria of ManchesterThesisStudies on electronic metal theory (1911)Doctoral adviserChristian ChristiansOtheren academic advisorsJ. J. ThomsonErnest RutherfordDoctoral studentsHendrik KramersI. H. UsmaniOther notable studentsLev LandauInfluencesErnest RutherfordHarald HøffdingInfluencedWerner HeisenbergWolfgang PauliPaul DiracLise MeitnerMax DelbrückKaren Barad Signature Niels Henrik David Bohr (Danish: [ˈne̝ ls ˈpoưư]; October 7, 1885 – November 18, 1962) was a Danish physicist who made fundamental contributions to the understanding of atomic structure and quantum theory, for which he received the Nobel Prize in Physics in 1922. Bohr was also a philosopher and promoter of scientific research. Bohr developed the Bohr model of the atom, in which he proposed that electron energy levels are discrete and that electrons rotate in stable orbits around the atomic nucleus, but can jump from one energy level (or orbit) to another. Although the Bohr model has been supplanted by other models, its underlying principles remain valid. He conceived the principle of complementarity: that items could be analyzed separately in terms of contradictory properties, such as behaving like a wave or a particle flow. The notion of complementarity dominated Bohr's thinking in both science and philosophy. Bohr founded the Institute of Theoretical Physics at the University of Copenhagen, now known as the Niels Bohr Institute, opened in 1920. Bohr mentored and collaborated with physicists such as Hans Kramers, Oskar Klein, George de Hevesy and Werner Heisenberg. He predicted the existence of a new element similar to zirconium, which was called hafnium, named after the Latin name of Copenhagen, where it was discovered. Later, the bohrium element was named after him. During the 1930, Bohr helped refugees from Nazism. After Denmark was occupied by the Germans, Germans, had a famous meeting with Heisenberg, who had become the head of the German nuclear weapons project. In September 1943, the news reached Bohr that he was about to be arrested by the Germans, and he fled to Sweden. From there, he was taken to Britain, where he joined the British Tube Alloys nuclear weapons project, and was part of the British mission to the Manhattan Project. After the war, Bohr called for international cooperation in nuclear power. He was involved with the creation of CERN and the Risø Research Establishment of the Danish Atomic Energy Commission and became the first president of the Nordic Institute of Theoretical Physics in 1957. In the early years, Bohr was born in Copenhagen, Denmark, on October 7, 1885, the second of three children of Christian Bohr,[1][2] professor of physiology at the University of Copenhagen, and Ellen Bohr (nee Adler), who was the daughter of David B. Adler of the wealthy Danish banking family Adler. He had an older sister, Jenny, and a younger brother, Harald. Jenny became a teacher, while Harald became a mathematician and football player who played for the Danish national team at the 1908 Summer Olympics in London. Niels was also a passionate player, and the two brothers played several games for Akademisk Boldklub (Academic Football Club), with Niels as goalkeeper. [4] Bohr as a young bohr was educated at Gammelholm Latin School, starting when he was seven. [5] In 1903, Bohr enrolled as a graduate of the University of Copenhagen. His course was physics, which he studied with Professor Christian Christiansen, the only professor of physics at the university at the time. He also studied astronomy and mathematics under Professor Thorvald Thiele, and philosophy under Professor Harald Høffding, a friend of his father. [7] In 1905, a gold medal competition was sponsored by the Royal Danish Academy of Sciences and Letters to investigate a method for measuring the surface tension of liquids that had been proposed by Lord Rayleigh in 1879. This involved measuring the frequency of oscillation of the radius of a water jet. Bohr conducted a series of experiments using his father's laboratory at the university; the university itself had no physics laboratory. To complete his experiments, he had to make his own glasses, creating test tubes with the necessary elliptical sections. He went beyond the original task, incorporating improvements in Rayleigh's theory and method, taking into account the viscosity of water, and working with finite amplitudes rather than just infinitesimal. His essay, which he presented at the last minute, won the award. He later submitted an improved version of the article to the Royal Society in London for publication in the Philosophical Transactions of the Royal Society. [10] Harald became the first of the two Bohr to obtain a master's degree, which he won for mathematics in April 1909. It took Niels another nine months to earn his in metals theory, a topic attributed by his supervisor, Christiansen. Bohr later elaborated his master's thesis on his much larger doctor of philosophy thesis (dr. phil.) thesis. He researched the literature on the subject, establishing himself in a model postulated by Paul Drude and elaborated by Hendrik Lorentz, in which electrons in a metal are considered as a gas. Bohr extended Lorentz's model, but was still unable to explain phenomena such as the Hall effect, and concluded that electron theory could not fully explain the magnetic properties of metals. The thesis was accepted in April 1911,[11] and Bohr conducted his formal defense on May 13. Harald had received his doctorate the previous year. [12] Bohr's thesis was groundbreaking, but attracted little interest outside Scandinavia because it was written in Danish, a requirement of the University of Copenhagen at the time. In 1921, Dutch physicist Hendrika Johanna van Leeuwen would independently derive a theorem from Bohr's thesis that is now known as bohr-van Leeuwen's theorem. Bohr and Margrethe Nørlund on their engagement in 1910. In 1910, Bohr met Margrethe Nørlund, sister of mathematician Niels Erik Nørlund. [14] Bohr renounced his membership of the Church of Denmark on April 16, 1912, and he and Margrethe were married in a civil ceremony at Slagelse Prefecture on August 1. Years later, his brother Harald also left the church before marrying. Bohr and Margrethe had six children. The eldest, Christian, died in a boating accident in 1934,[17] and another, Harald, died of infantile meningitis. Aage Bohr became a successful physicist, and in 1975 was awarded the Nobel Prize in Physics, like his father. Hans Bohr [da] became a doctor; Erik Bohr [da], chemical engineer; and Ernest, a lawyer. [18] Like his uncle Harald, Ernest Bohr became an Olympian, playing field hockey for Denmark at the 1948 Summer Olympics in London. [19] Bohr Physics model Main article: Bohr model In September 1911, Bohr, supported by a grant from the Carlsberg Foundation, traveled to England. At the time, it was where most of the theoretical work on the structure of atoms and molecules was being done. He met J. J. Thomson of Cavendish Laboratory and Trinity College, Cambridge. He attended lectures on electromagnetism given by James Jeans and Joseph Larmor, and did some research on khakis, but failed to impress Thomson. [21] He had more success with younger physicists such as Australian William Lawrence Bragg,[23] and New Zealander Ernest Rutherford, whose small central core of 1911, the Rutherford model of the atom had challenged Thomson's plum pudding model in 1904. [24] Bohr received an invitation from postdoctoral fellow at the Victoria University of Manchester,[25] where Bohr met George de Hevesy and Charles Galton Darwin (whom Bohr referred to as the grandson of the real Darwin). Bohr returned to Denmark in July 1912 for his wedding, and traveled through England and Scotland on his honeymoon. On his return, he became a privatdocent at the University of Copenhagen, giving lectures on thermodynamics. Martin Knudsen put Bohr's name to a professor, who was approved in July 1913, and Bohr then began teaching medical students. His three articles, which later became famous as the trilogy, were published in the Philosophical Journal in July, September and November of that year. [30] He adapted Rutherford's nuclear structure to Max Planck's quantum theory and thus created his Bohr model of the atom. [29] Planetary models of atoms were not new, but Bohr's treatment was. [32] Taking Darwin's role in 1912's role in the role of electrons in the interaction of alpha particles with a nucleus as its starting point,[33][34] he advanced the theory of electrons traveling in orbits around the nucleus of the atom, with the chemical properties of each element being largely determined by the number of electrons in the outer orbits of their atoms. He introduced the idea that an electron could fall from a higher-energy orbit to a lower one, in the process that emits a quantum of discrete energy. This became a basis for what is now known as the old quantum theory. [36] The Bohr model of the hydrogen atom. A negatively charged electron, confined to an atomic orbital, orbits a small positively charged nucleus; a quantum leap between the orbits is accompanied by an emitted or absorbed amount of electromagnetic radiation.