| PLANCK, MAX (1858-1947), German physicist, was born in Kiel, April 23, 1858. He studied in the universities of Munich and Herlin, became an assistant in the University of Munich, and in 1885 was appointed professor of physics in Kiel. In 1889 he went to Berlin as professor of physics. Planck is justly regarded as the father of the quantum theory. His early interest in thermodynamics led him into the study of the energy distribution in the spectrum of black-body radiation, for which classical statistical mechanics was unable to account. In 1901 Planck showed that a formula fitting the experimental results could he derived by assuming that radiant energy could he emitted or absorbed only in multiples of a quantum (smallest unit) of energy, the size of which was proportional to the frequency of the radiation being emitted or absorbed. For some time he regarded this explanation as being merely a convenient fiction not corresponding to the true mechanism of radiation, and it was Albert Einstein who embraced the energy quantum as a genuine advance in radiation theory. Planck was awarded the 1918 Nobel Prize in physics for his work on black-body radiation. He served for a time as editor of the Annalen der Physik. He was a foreign member of the Royal Society (England) and an honorary member of the American Physical Society. During World War II, Planck opposed Nazi policies and suffered considerable hardship. The end of his life was embittered by the execution of his only son for taking part in the abortive attempt on July 20, 1944, to assassinate Adolf Hitler. He died in Gottingen, October 3, 1947. |