Willem Hendrik Keesom

Willem Hendrik Keesom (/ˈkeɪsoʊm/^[1][2]) (21 June 1876, Texel – 3 March 1956, Leiden) was a Dutch physicist who, in 1926, invented a method to freeze liquid helium. He also developed the first mathematical description of dipole–dipole interactions in 1921. Thus, dipole–dipole interactions are also known as Keesom interactions. He was previously a student of Heike Kamerlingh Onnes, who had discovered superconductivity (a feat for which Kamerlingh Onnes received the 1913 Nobel Prize in Physics).

Willem Keesom
Willem Keesom in 1926
Born	21 June 1876 (1876-06-21) Texel, Netherlands
Died	3 March 1956 (1956-03-04) (aged 79) Leiden, Netherlands
Known for	helium
Scientific career
Fields	physics
Doctoral advisor	Johannes Diderik van der Waals

He also discovered the lambda point transition specific-heat maximum between Helium-I and Helium-II in 1930.^[3]

In 1924 he became member of the Royal Netherlands Academy of Arts and Sciences.^[4] In 1966, the minor planet 9686 Keesom was named after him.

See also

• Timeline of low-temperature technology