Heike Kamerlingh Onnes (1853-1926)

Heike Kamerlingh Onnes was Dutch winner of the Nobel Prize for Physics in 1913 for his work on
low-temperature physics and his production of liquid helium. He discovered superconductivity, the almost total lack of electrical resistance in certain materials when cooled to a temperature near absolute zero.

Heike Kamerlingh Onnes was born on September 21, 1853, at Groningen, The Netherlands. His father, Harm Kamerlingh Onnes, was the owner of a brickworks near Groningen; his mother was Anna Gerdina Coers of Arnhem, the daughter of an architect.

After spending the allotted time at the "Hoogere Burgerschool" in his native town (secondary school without classical languages), the director of which was the later Professor of Chemistry at Leyden J.M. van Bemmelen, he received supplementary teaching in Greek and Latin. In 1870 he entered the University of Groningen, obtained his "candidaats" degree (approx. B.Sc.) the following year, and then went to Heidelberg University as a student of the German physicists Robert Bunsen and Gustav Kirchhoff from October 1871 until April 1873. Kamerlingh Onnes' talents for solving scientific problems was already apparent in 1871, when at the age of 18 he was awarded a Gold Medal for a competition sponsored by the Natural Sciences Faculty of the University of Utrecht, followed the next year by a Silver Medal for a similar event at the University of Groningen. When working with Kirchhoff he also won the "Seminarpreis", entitling him to occupy one of the two existing assistantships under Kirchhoff.

Thereafter he returned to Groningen, where he passed his "doctoraal" examination (approx. M.Sc.) in 1878 and obtained the doctor's degree in 1879 with a remarkable thesis "Nieuwe bewijzen voor de aswenteling der aarde" (New proofs of the rotation of the earth). In his doctoral thesis, he gave both theoretical and experimental proofs that Foucault's well-known pendulum experiment should be considered as a special case of a large group of phenomena which can be used to prove the rotation of the Earth.

Meanwhile in 1878 he had become assistant at the Polytechnicum (Polytechnic School) at Delft, working under Bosscha, in whose place he also lectured in 1881 and 1882, during which time he was in close contact with van der Waals, professor of physics in Amsterdam. In 1881 he published a paper Algemeene theorie der vloeistoffen (General theory of liquids), which dealt with the kinetic theory of the liquid state, approaching Van der Waals' law of corresponding states from a mechanistic point of view. This work can be considered as the beginning of his life-long investigations into the properties of matter at low temperatures. In his inaugural address De beteekenis van het quantitatief onderzoek in de natnurkunde (The importance of quantitative research in physics) he arrived at his well-known motto "Door meten tot weten" (Knowledge through measurement), an appreciation of the value of measurements which concerned him throughout his scientific career.

Kamerlingh Onnes was interested in investigating the electrical properties of pure metals with no impurities in this newly available region of low temperatures. The question was: will the resistance increase, or decrease or remain constant when cooling the samples? He decided to work with mercury which can be repeatedly distilled at room temperature in order to obtain a pure sample. What happened was completely unpredictable: Onnes found (1911) that when cooling the pure mercury tubes to a temperature of 4.2 °K the resistance suddenly dropped to zero. He termed this phenomenon "superconductivity." He showed similar results in some other metals, for instance in tin and lead and in 1914 he established a permanent current, or what he called a "persistent supercurrent", in a superconducting coil of lead. His systematic researches on superconductivity (begun in 1911) were of extreme importance because of their bearing on the theory of electrical conduction in solids. It was 46 years before John Bardeen, Leon N. Cooper and J. Robert Schrieffer established the theoretical foundations that best explained superconductivity.