Planck, Max Karl Ernst 1858-1947
German theoretical physicist and Nobel Prize winner

Born in Kiel, Schleswig-Holstein, he studied at Munich University and under Gustav Kirchhoff and Hermann von Helmholtz at Berlin University, where he succeeded the former in the professorship (1889-1926). His work on the law of thermodynamics and black body radiation led him to abandon classical dynamical principles and formulate the quantum theory (1900), which relied on Ludwig Boltzmann's statistical interpretation of the second law of thermodynamics, and assumed energy changes to take place in small discrete instalments or quanta. This successfully accounted for and predicted certain phenomena inexplicable in the classical Newtonian theory. Albert Einstein's application of the quantum theory to light (1905) led to the theories of relativity, and in 1913 Niels Bohr successfully applied it to the problems of sub-atomic physics. Planck was awarded the Nobel Prize for physics (1918). In 1930 he was elected president of the Kaiser Wilhelm Institute, but resigned in 1937 in protest against the Nazi regime. He was eventually reappointed as president of the renamed Max Planck Institute.

Bibliography: J L Heilbron, The Dilemmas of an Upright Man: Max Planck as Spokesman for German Science (1986)