Bohrs+Model

**Niels Henrik David Bohr** was born in Copenhagen on October 7, 1885. His father was Christian Bohr, a Professor of Physiology at Copenhagen University. Niels Bohr’s Mother was Ellen, née Adler. Niels had a younger brother Harald. After matriculation at the Gammelholm Grammar School in 1903, he went to Copenhagen University where he came under the guidance of professor C. He got his master’s in Physics in 1909 and went one got his Doctor’s degree in 1911. In the fall of 1911 he made a stay at Cambridge, where he profited by following the experimental work going on in the Cavendish Lab. Sir J.J. Thomson was his guidance at eh same time as he pursued his own theoretical studies. In the spring of 1912 he was working under Professor Rutherford as Rutherford was doing his own experiments before he found out the atomic nucleus. In 1913-1914 Bohr held a Lectureship in Physics at Copenhagen University and in 1914-1916 a similar appointment at the Victoria University in Manchester. In 1916 he was appointed Professor of Theoretical Physics at Copenhagen University, and since 1920 (until his death in 1962) he was at the head of the Institute for Theoretical Physics, established for him at that university. In 1922 the foundation recognized his work of the atomic structure and Niels Bohr won the Nobel Prize. Sadly on November 18, 1962 Niels Henrik David Bohr died.

__Bohr's Model__
In Bohr's model the nucleus is surrounded by shells of possible orbits. The electron can only be in one of the orbits. There is a "ground state" orbit. The electron can get no closer to the nucleus than this. Higher orbits are called "excited states". An electron in an atom can get knocked into an excited state by getting hit by another atom. Each orbit has a specific energy = Eorbit A photon can only be absorbed when an electron jumps from a lower orbit to a higher one (this is another way to get an electron into an excited state) But this can only happen if the photon's energy is equal to the difference in energy between electron's orbits. This is what allows a jump to be made.

E photon = Eorbit2 - Eorbit1