Born: 26 August 1882, Hamburg, Germany
Died: 21 May 1964, Göttingen, West Germany (now Germany)
Affiliation at the time of the award: Goettingen University, Göttingen, Germany
Prize motivation: "for their discovery of the laws governing the impact of an electron upon an atom"
Field: atomic physics
James Franck received his Nobel Prize one year later, in 1926.
Prize share: 1/2
Following Niels Bohr's theory for the structure of the atom, an experiment to verify it was made by James Franck and Gustav Hertz in 1913. A potential difference was applied to a tube containing a low pressure gas. When the potential difference was increased, the current through the tube also increased until it reached a certain voltage, then it was suddenly reduced. The result gave support for Bohr's theory in which the electrons have only specific discrete energies. The freely moving electrons, could at a certain energy, make the electrons of the gas atom to move to a new orbit.