Date context
1858–1947
Beginning with thermodynamics
Born in Kiel, Planck studied physics in Munich and Berlin. His early work concerned the second law of thermodynamics and entropy, followed by academic appointments in Kiel and Berlin. The search for general laws of heat and energy shaped his later radiation research.
The problem of black-body radiation
The black-body problem concerned the distribution of radiated energy across wavelengths or frequencies at a given temperature. In 1900 Planck proposed a formula consistent with measurements and then sought a physical derivation, moving from an empirical relation toward an explanation.
Introducing energy quanta
In December 1900 his derivation introduced finite energy elements related to frequency through the quantity later called Planck’s constant. This step conflicted with a wholly continuous classical treatment; it was not yet Einstein’s subsequent theory of localized light quanta.
Later quantum theory and scientific institutions
This work earned the Nobel Prize designated for 1918. Einstein, Bohr and others subsequently extended quantum ideas. Planck also held important organizational roles in German science; his research, institutional responsibilities and the later society bearing his name belong to distinct historical settings.