Wilhelm Wien was a German physicist and Nobel-Prize winner who pioneered the study of quantum physics.
Wien was born in East Prussia in 1864 to a landholding family. He broke away from his father’s life as a gentleman farmer to study mathematics and physics at the Universities of Göttingen and Berlin. Between 1883 and 1885, he worked in Hermann von Helmholtz’s laboratory. In 1886, he took a doctorate with a thesis on the diffraction of light on metal and on the influence of materials on the color of refracted light.
After a brief absence to manage his father’s estate, Wien returned to Helmholtz’s laboratory, and, in 1896, began a series of professorships in physics that culminated in his appointment as Professor of Physics in Munich in 1920.
From early in his career, Wien performed landmark research in thermodynamics. In 1893, he announced what would later be called the law of displacement: that wavelength changes with temperature. In 1896, he published the formula of Wien, which described the composition of radiation of an ideal body, which he called a black body. This work enabled Max Planck to use quantum physics to answer the problem of thermal radiation in thermal equilibrium. It also earned Wien the 1911 Nobel Prize in physics.
In the late 1890s, Wien studied cathode rays, confirming that they were made of fast moving negatively-charged particles, or electrons, that were about two thousand times lighter than hydrogen atoms. He then analyzed canal rays, finding that they were the positive equivalent of electrons and were never heavier than them. This research led to the development of the spectrography of masses twenty years later.