Heike Kamerlingh Onnes was a Dutch physicist who discovered superconductivity in 1911, a phenomenon occurring in certain materials at low temperatures, characterized by the complete absence of electrical resistance and the damping of the interior magnetic field. Onnes cooled mercury in his laboratory to 452 degrees below zero Fahrenheit (F); this is close to the temperature of "absolute zero" (-459° F) at which the motion of all individual atoms stops. Subsequent applications of superconducting materials include high-speed magnetic-levitation trains, magnetic-resonance-imaging (MRI) equipment, ultra-high-speed computer chips, high-capacity digital memory chips, energy storage systems, and gyroscopes for earth-orbiting satellites. Onnes was awarded the Nobel Prize in Physics in 1913 for his discovery of superconductivity.

From 1882 to 1923 Kamerlingh Onnes served as professor of experimental physics at the University of Leiden. In 1904 he founded a very large cryogenics laboratory and invited other researchers to the location, which made him highly regarded in the scientific community. In 1908, he was the first physicist to liquify helium, using the Hampson-Linde cycle and cryostats. Using the Joule-Thomson effect, he lowered the temperature to less than one degree above absolute zero, reaching 0.9 K. At the time this was the coldest temperature achieved on earth. The original equipment is at the Boerhaave Museum in Leiden.

Sources

• Cleveland, Cutler (Lead Author); Peter Saundry (Topic Editor). 2007. "Onnes, Heike Kamerlingh." In: Encyclopedia of Earth. Eds. Cutler J. Cleveland (Washington, D.C.: Environmental Information Coalition, National Council for Science and the Environment). [Published in the Encyclopedia of Earth March 8, 2007; Retrieved November 18, 2009]. 
• Wikipedia Contributors, Heike Kamerlingh Onnes, Wikipedia The Free Encyclopedia, Accessed 18 November 2009.