Max Karl Ernst Ludwig Planck

Max Karl Ernst Ludwig Planck


Born: 23 April 1858 in Kiel, Schleswig-Holstein, Germany
Died: 4 Oct 1947 in Göttingen, Germany



Max Planck came from an academic family, his father being professor of law at Kiel and both his grandfather and great-grandfather had been professors of theology at Göttingen. In 1867 Planck's family moved to Munich and he attended school there. He did well at school, but not brilliantly, usually coming somewhere between third and eighth in his class.

In 1874, at the age of 16, he entered the University of Munich. Before he began his studies he discussed the prospects of research in physics with Philipp von Jolly, the professor of physics there, and was told that physics was essentially a complete science with little prospect of further developments. Fortunately Planck decided to study physics despite the bleak future for research that was presented to him.

In [7] Planck describes why he chose physics:-

The outside world is something independent from man, something absolute, and the quest for the laws which apply to this absolute appeared to me as the most sublime scientific pursuit in life.
Planck then studied at Berlin where his teachers included Helmholtz and Kirchhoff. He later wrote that he admired Kirchhoff greatly but found him dry and monotonous as a teacher. Planck returned to Munich and received his doctorate at the age of 21 with a thesis on the second law of thermodynamics. He was then appointed to a teaching post at the University of Munich in 1880 and he taught there until 1885.

In 1885 Planck was appointed to a chair in Kiel and held this chair for four years. After the death of Kirchhoff in 1887, Planck succeeded him in the chair of theoretical physics at the University of Berlin in 1889. He was to hold the Berlin chair for 38 years until he retired in 1927.

While in Berlin Planck did his most brilliant work and delivered outstanding lectures. He studied thermodynamics in particular examining the distribution of energy according to wavelength. By combining the formulas of Wien and Rayleigh, Planck announced in 1900 a formula now known as Planck's radiation formula. In a letter written a year later Planck described proposing the formula saying:-

... the whole procedure was an act of despair because a theoretical interpretation had to be found at any price, no matter how high that might be.
Within two months Planck made a complete theoretical deduction of his formula renouncing classical physics and introducing the quanta of energy. At first the theory met resistance but due to the successful work of Niels Bohr in 1913, calculating positions of spectral lines using the theory, it became generally accepted. Planck himself in [7] explains how despite having invented quantum theory he did not understand it himself at first:-
I tried immediately to weld the elementary quantum of action somehow in the framework of classical theory. But in the face of all such attempts this constant showed itself to be obdurate ... My futile attempts to put the elementary quantum of action into the classical theory continued for a number of years and they cost me a great deal of effort.
Planck received the Nobel Prize for Physics in 1918.

Planck took little part in the further development of quantum theory, this being left to Paul Dirac and others. Planck took on administrative duties such as Secretary of the Mathematics and Natural Science Section of the Prussian Academy of Sciences, a post he held from 1912 until 1943. He had been elected to the Academy in 1894.

Planck was president of the Kaiser Wilhelm Gesellschaft, the main German research organisation, from 1930 until 1937. He remained in Germany during World War II through what must have been times of the deepest difficulty since his son Erwin was executed for plotting to assassinate Hitler. In [4] Heilbron describes the impact of wars on Planck and his family:-

He would remember, even in his old age, the sight of Prussian and Austrian troops marching into his native town when he was six years old. Throughout his life, war would cause him deep personal sorrow. He lost his eldest son during World War I. In World War II, his house in Berlin was burned down in an air raid. In 1945 his other son was executed when declared guilty of complicity in a plot to kill Hitler.
After World War II he again became president of the Kaiser Wilhelm Gesellschaft in 1945-1946 for the second time defending German science through another period of exceptional difficulty.