Max Planck Formulates Quantum Theory

Max Planck, German theoretical physicist who discovered quantum theory.
German theoretical physicist Max Planck (1858 - 1947), who formulated the quantum theory and was awarded the Nobel prize for Physics in 1918. (Photo by Hulton Archive/Getty Images)

In 1900, German theoretical physicist Max Planck revolutionized the field of physics by discovering that energy does not flow evenly but is instead released in discrete packets, which he called "quanta." Planck created an equation to predict this phenomenon, which includes a constant now known as "Planck's constant." Planck's discovery ended what many people now call "classical physics" and began the study of quantum physics.

The Problem

Despite feeling that all was already known in the field of physics, there was still one problem that had plagued physicists for decades -- they could not understand the surprising results they continued to get from heating black bodies (a surface that absorbs all frequencies of light that hits it).

Try as they might, scientists could not explain the results using classical physics.

Max Planck

Max Planck was born in Kiel, Germany on April 23, 1858 and was considering becoming a professional pianist before a teacher turned his attention to science. Planck went on to receive degrees from the University of Berlin and the University of Munich.

After spending four years as an associate professor of theoretical physics at Kiel University, Planck moved to the University of Berlin, where he became a full professor in 1892.

Planck's passion was thermodynamics. While researching black body radiation, he too kept running into the same problem as other scientists.

Classical physics could not explain the results he was finding.

The Equation

In 1900, 42-year-old Max Planck discovered an equation that explained the results of these tests. The equation is E=Nhf, with E=energy, N=integer, h=constant, f=frequency. In determining this equation, Planck came up with the constant (h), which is now known as "Planck's constant."

The really amazing part of Planck's discovery was that energy, which appears to be emitted in wavelengths, is actually discharged in small packets (quanta).

This new theory of energy revolutionized physics and opened the way for Albert Einstein's theory of relativity.

Life for Max Planck After His Discovery

At first, the magnitude of Max Planck's discovery was not fully understood. It wasn't until Einstein and others used Planck's theory for even further advancements in physics that the revolutionary nature of his discovery was realized.

By 1918, the scientific community was well aware of the discovery's importance and awarded Max Planck the Nobel Prize in Physics.

Max Planck continued to research and contribute further to the advancement of physics, but nothing compared to his 1900 findings.

Tragedy in His Personal Life

In his personal life, Max Planck suffered greatly. Planck's first wife died in 1909 and then tragedy struck all four of their children. Karl, the oldest, died in World War I. Twin girls, Margarete and Emma, both later died in childbirth. And the youngest son, Erwin, was implicated in the failed July Plot to kill Hitler and was hanged.

In 1911, Planck did remarry and had one son, Hermann.

Max Planck made the decision to stay within Germany during World War II. Using his clout, Planck tried to stand up for Jewish scientists, but with little success. In protest, Planck did resign as president of the Kaiser Wilhelm Institute in 1937.

In 1944, a bomb during an Allied air raid hit his house, destroying his scientific notebooks along with his other possessions.

Max Planck died on October 4, 1947 at the age of 89.