Willem Hendrik Keesom

Willem Hendrik Keesom ( born June 21, 1876 Texel, The Netherlands, † March 24, 1956 in Oegstgeest ) was a Dutch physicist.

Keesom was a farmer's son and studied at the University of Amsterdam. In 1904 he received his doctorate in Heike Kamerlingh Onnes in Leiden, the research assistant he was, and was involved in its work for the liquefaction of helium it. 1917 to 1923 he taught at the Veterinary School in Utrecht and from 26 September 1923 he was professor of experimental physics in Leiden, where he became the successor of Kamerlingh Onnes in his laboratory.

His main area of ​​work was the low-temperature physics. In 1926 he invented a method to solidify helium pressure, which his teacher Kamerlingh Onnes, who first liquefied helium in 1908, was not successful. He also found evidence of the phase transition to superfluidity of helium at the lambda point, and measured 1932 Clusius the anomaly of the course of the heat capacity at this phase transition. He also developed a mathematical theory of dipole -dipole interaction.

With Kamerlingh Onnes he wrote an article state equations in the Encyclopedia of Mathematical Sciences.

In 1924 he was elected to the Royal Netherlands Academy of Sciences.