German physicist. Seeking to explain the experimental spectrum (distribution of electromagnetic energy according to wavelength) of black body radiation, he introduced the hypothesis (1900) that oscillating atoms absorb and emit energy only in discrete bundles (called quanta) instead of continuously, as assumed in classical physics. The success of his work and subsequent developments by Albert Einstein, Niels Bohr, Werner Heisenberg, Erwin Schrodinger, and others established the revolutionary quantum theory of modern physics, of which Planck is justly regarded as the father. In 1918, Planck received the Nobel Prize in physics for his work on black body radiation. He was professor at the Univ. of Berlin (1889-1928) and president (1930-35) of the Kaiser Wilhelm Society for the Advancement of Science, Berlin, which after World War II was reconstituted as part of the Max Planck Institutes. He was an editor of the Annalen der Physik and member of the Royal Society (London) and the American Physical Society. His name is honored in Planck's constant. English translations of his works include A Survey of Physics (1925, new ed. 1960), Introduction to Theoretical Physics (5 vol., 1932-33), Treatise on Thermodynamics (3d rev. ed. 1945), and Scientific Autobiography and Other Papers (1949).