Niels Bohr

            Niels Bohr was a Danish physicist who made many contributions to nuclear physics and the understanding of the atomic structure.
             Niels Henrick David Bohr was born on October 7, 1985 in Copenhagen, Denmark. His father, Christian, was a professor at the University of Copenhagen and his mother, Ellen, came from a Jewish family prominent in banking. Niels also had a younger brother, Harald, who grew up to be a brilliant mathematician.
             Bohr was interested in science from a very young age, his parents encouraged him to keep learning more about it. Niels went to the University of Copenhagen, while he was there he won a gold medal from the Royal Danish Academy of Sciences and Letters. He got this award for his analysis on surface tensions. In 1911 he received his doctorate for a thesis on the electron theory of metals.
             In March 1912, Bohr moved to Manchester, England, where he joined Ernest Rutherford and his group in studying the structure of the atom. He was among the first to see that the atomic number indicates the position of an element on the periodic table. He also realized that the physical and chemical properties depend on the electrons moving around in their nuclei. Rutherford's nuclear model was unstable, until Bohr introduced the quantum theory. Niels figured that an atom could only exist in a set of stable states, each characterized by its value of energy. He also stated that an atom would not emit light or radiation while it was in one of its stable positions, rather it only would while in transition between states. This meant an atom could not emit radiation continuously, but only in little steps.
             In the summer of 1912, Bohr returned to Copenhagen and got married to Margreth Norlund, and continued his research on the physics of the atom.
             In 1916, Niels Bohr became a professor in Copenhagen. While there, he served as the director for the new Institute of Theoretical Physics. Throughout the early 1920's, Bohr tried to develop a consistent quantum theory that would replace classical mechanics at the atomic level.