Heisenburg studied quantum mechanics and quantum theory. At the time the Bohr model was in use, where electrons were describes as being in a a fixed orbit. However, the model only worked with the hydrogen atom. Heisenburg developed the uncertainty principle which stated that the more precisely the position of a particle is known, then the less precisely the momentum of the particle is known. This did not change much of Bohr's model, only that the precise location of the electron cannot be known. Bohr won the Nobel Prize in Physics in 1932.