Heike Kamerlingh-Onnes (1853-1926)

Heike Kamerlingh-Onnes was born on September 21, 1853 in Groningen, the Netherlands. His father owned a roof-tiling factory near Groningen while his mother, the daughter of an architect, had an artistic impact on her children. While his siblings became involved in the arts, Onnes leaned more towards science, although a remnant of his early interest in poetry is showcased in his laboratory motto, “To knowledge through measurement.” Due to his lack of exposure to classical languages during secondary school, Onnes received supplementary teaching in Greek and Latin before entering the University of Groningen in 1870 to study physics. In 1871, he transferred to Heidelberg University, where he studied with the chemist Robert Bunsen and physicist Gustav Kirchhoff. By 1871, Onnes' talent for solving scientific problems was already apparent. In that year, 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. While studying under Kirchhoff, he won a competition entitling him to occupy one of the two existing assistantships under Kirchhoff. In 1873 Onnes returned to Groningen, where five year later he would defend his remarkable doctoral thesis entitled “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. Towards the end of his doctorate work, he became acquainted with Johannes Diderik van der Waals, a professor of physics at the University of Amsterdam. Onnes’ 1881 paper, “General Theory of Liquids”, dealt with the kinetic theory of the liquid state, approaching van der Waals' law of corresponding states from a mechanistic point of view. This paper can be considered as the beginning of his life-long investigations into the properties of matter at low temperatures. After teaching at the Polytechnic School at Delft (Netherlands) from1880-1882, Onnes became a professor of experimental physics at Leiden University (1882-1924). Upon his appointment to the Physics Chair at Leiden, he reorganized the physical laboratory into a cryogenic laboratory which enabled him to gather experimental evidence for the atomic theory of matter and to give experimental support to van der Waals’ corpuscular theory of gases at low temperatures. Nitrogen and oxygen had been liquefied in small amounts as early as 1877 at 77 K and 90 K respectively, but for the purposes of his research, Onnes required large amounts of liquid. In 1892 he succeeded in building an apparatus for producing these large amounts. After nitrogen and oxygen, the next gas of importance to liquefy became hydrogen. The difficulty in liquefying hydrogen was that the temperature required was significantly closer to absolute zero (- 273°C), where theoretically pressure becomes zero, making the construction of a liquefying apparatus difficult. Although hydrogen was liquefied in 1896, Onnes was the first to constructed an apparatus able to produce relatively large amounts of liquid hydrogen utilizing Joule-Thomson expansion, which he did in 1906.

Helium gas, discovered on earth in 1895, became Onnes’ next project. Using liquid hydrogen and liquid air as coolants in a new apparatus, he attempted to produce liquid helium on July 10, 1908. With the thermometer refusing to drop below 4.2 K without a sign of the production of liquid helium, it took the illumination of the collection barrel to discover within it the existence of liquid helium. By reducing the pressure, Onnes was able to bring the temperature of the helium down to 1.7 K, the nearest approach to absolute zero achieved at that point in time. It was on account of these low- temperature studies that he was awarded the Nobel Prize on December 11, 1913. The liquefying of helium led Onnes to his second major discovery, that of the phenomenon known as superconductivity, a phrase coined by Onnes himself. At this time it was well known that the electrical resistance in a metal decreased with temperature. However, the electrical resistance in metal at temperatures approaching absolute zero were not known. To investigate this, Onnes distilled liquid mercury to remove any impurities from the metal before solidifying it into wire. At all measured temperatures up to liquid-helium temperature, a decrease in resistance with falling temperature was measured. However, at the temperature for liquid-helium, which was still higher than absolute zero, the resistance appeared to have completely vanished. Onnes published his findings in November of 1911 as “On the Sudden Change in the Rate at Which the Resistance of Mercury Disappears.” Subsequently, metals such as tin and lead were also found to exhibit the phenomenon of superconductivity if cooled sufficiently. Outside his scientific work, Onnes was a man of great personal charm and philanthropic humanity. He was very active during and after the First World War in smoothing out political differences between scientists and in helping starving children in countries suffering from food shortages. In 1887 he married Maria Bijleveld with whom he had a son, Albert, who became a high-ranking civil servant at The Hague. Onnes’ health had always been somewhat delicate, and after a short illness, he died at Leiden on February 21, 1926.

Reference Materials

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Sacks, Oliver (2001) Uncle Tungsten-Memories of a Chemical Boyhood, p.303 and 320, Vintage Canada: Toronto. Kamerlingh Onnes, H. (1913) The Nobel Lecture: Investigations into the Properties of Substances at Low Temperatures, which Have Led, amongst Other Things, to the Preparation of Liquid Helium, http://www.nobelprize.org. http://www.transrapid.de/en/ http://www.ornl.gov/info/reports/m/ornlm3063r1/pt2.html http://superconductors.org/History.htm http://www.chemsoc.org/exemplarchem/entries/igrant/history_noflash.html http://eies.njit.edu/~tyson/supercon_papers/Onnes.pdf http://policy.iop.org/v_production/v9.html http://www.norskfysikk.no/nfs/epsbiografer/KAMERL~1.PDF http://www.lorentz.leidenuniv.nl/history/cold/cold.html http://hypertextbook.com/physics/modern/superconductivity/