Max Planck

A conundrum involving ultraviolet radiation led German physicist Max Planck to try a mathematical trick that ultimately pointed to the existence of what Planck decided to call quantum mechanics. Planck's dilemma was that if you heat up a box from which no light can escape, it should produce an infinite amount of ultraviolet radiation. But that doesn't happen. This situation is known as the ultraviolet catastrophe. To explain this phenomenon, Planck tried an equation that assumed light was not a wave -- which everyone at the time assumed it was -- but instead existed only with set amounts or "quanta" of energy. To his surprise, the equations worked [source: PBS].