Max Planck
Physicist · 1858-1947 · Physics, stage 3: Meet the physicists
Introduced the quantum of energy to make the blackbody spectrum come out right.
Overview
Max Planck worked in Berlin on thermodynamics and radiation. In 1900 he found a formula matching the measured spectrum of a hot body across all wavelengths, where the classical prediction failed badly at short wavelengths. To derive it he had to assume that energy is exchanged only in discrete units proportional to frequency, with the constant of proportionality now named after him. He regarded the assumption as a mathematical device rather than a claim about nature and spent years trying to eliminate it, which is why he later described it as an act of desperation. Einstein took the quanta literally in 1905, and Bohr applied them to the atom in 1913. Planck received the Nobel Prize in Physics in 1918. The Theory of Heat Radiation gives his own treatment of the subject.
Where to start reading
On the Law of Distribution of Energy in the Normal Spectrum 1901
The paper deriving the radiation law from the assumption that energy is exchanged in discrete quanta proportional to frequency.
The Theory of Heat Radiation 1914
His own textbook treatment of thermal radiation, in the English translation of the second German edition.
Part of
Sources
- Max Planck Nobel PrizeThe 1918 prize citation and biography from the Nobel archive.
- Max Planck English Wikipedia
- Max Planck Britannica
