Danish physicist Niels Bohr won the 1922 Nobel Prize in Physics for his investigation of the structure of atoms and the radiation emitted from them.
Bohr proposed a model of the atom in 1913 in which electrons occupy specific, quantized energy levels around the nucleus. Electrons can move between levels by absorbing or emitting energy, helping explain the discrete spectral lines observed in hydrogen.
His model did not provide the final form of quantum mechanics, but it was a crucial step toward modern atomic theory. Bohr later contributed to the interpretation of quantum mechanics and formulated the principle of complementarity.
Bohr founded the Institute of Theoretical Physics at the University of Copenhagen, now called the Niels Bohr Institute. His son Aage Bohr also became a Nobel Prize-winning physicist, receiving the 1975 Nobel Prize in Physics, which is why the two scientists are sometimes confused.