Photo from the Nobel Foundation archive.
Born: 17 February 1888, Sorau (now Zory), Germany (now Poland)
Died: 17 August 1969, Berkeley, CA, USA
Affiliation at the time of the award: Carnegie Institute of Technology, Pittsburgh, PA, USA
Prize motivation: "for his contribution to the development of the molecular ray method and his discovery of the magnetic moment of the proton."
Otto Stern received his Nobel Prize one year later, in 1944.
Prize share: 1/1
In certain respects, electrons and atoms act like rotating charges that generate magnetic fields. In a 1922 experiment, Otto Stern and Walter Gerlach passed a beam of silver atoms through an inhomogeneous magnetic field. According to classical physics, the beam should have spread out to a distribution, but instead, two distinct beams were observed. The result supported quantum physics' theory that electrons and atoms occupy only certain states of energy and movement. Angular momentum was proven to be quantized.