Building a low-temperature laboratory
After studies in Groningen and work with Bunsen and Kirchhoff in Heidelberg, Kamerlingh Onnes became professor in Leiden in 1882. He reorganised the laboratory for quantitative low-temperature research and established training for instrument makers and glassblowers.
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Liquid helium
In 1908 he liquefied helium. The liquid became both an object of study and a means of cooling other substances to investigate their electrical, magnetic and thermal properties. These low-temperature investigations earned him the 1913 physics prize.
Superconductivity
In 1911 the laboratory found that mercury lost measurable electrical resistance at temperatures only a few degrees above absolute zero. The phenomenon became known as superconductivity. Subsequent work examined other metals and persistent currents, making electrical behaviour at low temperatures a major laboratory research programme.