Dutch physicist and Nobel Prize laureate.
He was the eldest son of Harm Kamerlingh Onnes (24 June 1819, Groningen), a brickworks owner. His mother, Anna Gerdina Coers (12 July 1829 12 AM Arnhem – 10 April 1899, Zoeterwoude), was the daughter of the carpenter and architect Jacob Koers. They married 25 November 1852 in Arnhem and got seven children. His sister Meisina (5 Sept 1885 – 3 June 1860, Groningen) died early. His brother Menso Kamerlingh Onnes (25 Feb 1860, Brussel – 29 June 1925, Oegstgeest) became a painter. His nephew Harm Henrick Kamerlingh Onnes (15 Feb 1893, Zoeterwoude – 20 May 1985, Leiden) became a portrait painter and ceramist, noted for his on physical laws based ceramic art and portraits of prominent physicists.
In 1870, Kamerlingh Onnes attended the University of Groningen. From 1871-73, he went to Heidelberg to to study under Robert Bunsen and Gustav Kirchhoff. He got his masters degree in 1878 in Groningen and graduated magna cum laude with “Nieuwe bewijzen voor de aswenteling der aarde” on 10 July 1879 2PM. His New proofs of the rotation of the earth, were based on experiments with the pendulum of Léon Foucault, a theme that inspired the philosopher Umberto Eco to write his famous book Il pendolo di Foucault. Gustav Kirchhoff stimulated Kamerlingh Onnes to write his thesis.
From 1878 to 1882 he was assistant to the physicist Johannes Bosscha Jr. the director of the Delft Polytechnic. On instigation of Lorentz, he became at age 28 professor of experimental physics at the University of Leiden (1882-1923). In his inaugural speech held on 11 November 1882, he pleaded for “Meten is weten” (The numbers tell the tale), which became a Dutch expression. He was also credited for coining the word “enthalpy”.
In 1904, he founded the cryogenics laboratory, since 1932 named after him. He invited others (Ehrenfest, Bohr, Einstein) to cooperate with him, so the Kamerlingh Onnes Lab became a scientific community, from which also his students could profit. Here he exploited the Hampson-Linde cycle to cool materials to nearly absolute zero, to study their properties.
On 10 July 1908, he was the first to liquefy Helium at a temperature near 1.5 K, the coldest temperature ever achieved on earth at that time. The equipment employed can be seen in the Boerhaave Museum in Leiden. In 1911 he started to study the electrical conductivity of pure metals at low temperatures.
On 8 April 1911, he found that at at 4.2 K the resistance of a solid mercury wire immersed in liquid helium suddenly vanished. He reported that “Mercury has passed into a new state, which on account of its extraordinary electrical properties may be called the superconductive state”. He published several articles about “supraconductivity” or “superconductivity”.
He received several prizes for his work, including the 1913 Nobel Prize in Physics for: “his investigations on the properties of matter at low temperatures which led, inter alia, to the production of liquid helium”.
Personal
On 8 September 1887, he married Maria Adriana Wilhelmina Elisabeth Bijleveld (6 May 1861 – 1938) in Den Haag, the daughter of a jurist. They got a son Albert Harm Kamerlingh Onnes (5 July 1888), who became a jurist.
He died after a short illness, 21 February 1926, Leiden.

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