Niels Henrik David Bohr was born in Copenhagen, Denmark, on October 7, 1885, the second of three children born to Christian and Ellen Adler Bohr. Bohr's mother was a member of a wealthy Jewish banking family, and his father was a talented professor of physiology at the University of Copenhagen who conducted quantitative research on the physical processes underlying physiological functions. Bohr received his primary and secondary education at the Gammelholm School in Copenhagen.

In 1903, Bohr enrolled at the University of Copenhagen, where he majored in physics. His first research project was a precise measurement of the surface tension of water. He earned his bachelor of science degree in 1907, his master of science degree in 1909, and his doctorate in 1911, all at the University of Copenhagen. Bohr's thesis, which dealt with the electron theory of metals, convinced him that classical electromagnetic theory was inadequate for describing the quantitative properties of metals...