C. T. R. Wilson

Born on 14 February 1869 in Glencorse, Scotland, Charles Thomson Rees Wilson was a scientist who earned a share of the 1927 Nobel Prize in Physics for his invention of the cloud chamber. The inspiration for his prize-winning work came in the mountains of Scotland, where Wilson served as a meteorological observer. He decided to try to reproduce cloud formation in the laboratory. In 1895 Wilson produced his first cloud chamber, which supersaturates the air by expanding and cooling it. Wilson quickly realized that the device’s potential went far beyond understanding weather. In 1896 he fired a newly discovered form of radiation, x rays, through a cloud chamber and saw that it left a trail as water droplets condensed onto ions in the gas. Fifteen years later he tracked individual alpha particles and electrons. Throughout the first half of the 20th century, Wilson’s cloud chamber was indispensable for nuclear physics. The discovery of the positron and the first demonstrations of both the Compton effect and nuclear transmutation were made using Wilson chambers. (Photo credit: AIP Emilio Segrè Visual Archives, W. F. Meggers Gallery of Nobel Laureates)

Date in History: 14 February 1869