Kamerlingh-Onnes, Heike

[ kam erlingk aw nes] (1853–1926) Dutch physicist: liquefied helium for the first time and discovered superconductivity.

Kamerlingh-Onnes studied physics at Groningen and then spent 2 years in Heidelberg studying under . His special interest was then in finding new proofs of the Earth’s rotation, but after he became professor at Leiden in 1882 he concentrated on the properties of matter at low temperatures. Had liquefied nitrogen, and by cooling hydrogen with this and using the Joule–Thomson effect he had obtained liquid hydrogen. Kamerlingh-Onnes used an improved apparatus and similar principles. In 1908, by cooling helium with liquid hydrogen to about 18 K, and then using the Joule–Thomson effect (the cooling of a gas when it expands through a nozzle), he obtained liquid helium, which he found to boil at 4.25 K. If it was boiled rapidly by pressure reduction the temperature fell to just below 1 K, but it did not solidify. In 1911 he found that metals such as mercury, tin and lead at very low temperatures became superconductors, with near-zero electrical resistance. He won the Nobel Prize in 1913 for his work in low temperature physics, which he dominated until he retired in 1923. A theoretical explanation of superconductivity had to wait until the work and others in 1957.