Feature
Max Planck: Founder of Quantum Theory
Max Planck’s scientific career spanned some of the most turbulent times in German history—the Wilhelmian Empire, the Weimar Republic and the Third Reich. Through it all, he advanced and protected physics, with his own research evolving from theoretical physics that was firmly grounded in thermodynamics to his blackbody distribution law, which forced him to invoke non-classical ideas.
Portrait of Max Planck.
Wikimedia Commons/Deutsches Bundesarchiv
Max Planck didn’t set out to develop a new theory for how the universe works. When he started the work on blackbody radiation that would lead him to discover energy quanta, he had initially believed—like the other physicists of his day—that energy was a continuous quantity. He was disturbed that he had had to quantize it in order to get his equations to work. As he stated in his 1920 Nobel lecture: “It was completely indispensable for obtaining the correct expression for entropy [in his derivation of the blackbody distribution law] … it proved elusive and resistant to all efforts to fit it into the framework of classical physics.”
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