Editing Absolute zero (section)

===The race to absolute zero===
{{see also|Timeline of low-temperature technology}}
[[File:Leiden - Kamerlingh Onnes Building - Commemorative plaque.jpg|thumb|upright=1.2|Commemorative plaque in Leiden]]
With a better theoretical understanding of absolute zero, scientists were eager to reach this temperature in the lab.<ref name="MyUser_YouTube_November_23_2016c">{{Cite web |title=ABSOLUTE ZERO – PBS NOVA DOCUMENTARY (full length) |url=https://www.youtube.com/watch?v=mTFRgosx4aQ&t=894s |url-status=dead |archive-url=https://web.archive.org/web/20170406015107/https://www.youtube.com/watch?v=mTFRgosx4aQ |archive-date=6 April 2017 |access-date=23 November 2016 |newspaper=YouTube}}</ref> By 1845, [[Michael Faraday]] had managed to liquefy most gases then known to exist, and reached a new record for lowest temperatures by reaching {{convert|-130|C|F K}}. Faraday believed that certain gases, such as oxygen, nitrogen, and [[hydrogen]], were permanent gases and could not be liquefied.<ref>[http://www.scienceclarified.com/Co-Di/Cryogenics.html Cryogenics]. Scienceclarified.com. Retrieved on 22 July 2012.</ref> Decades later, in 1873 Dutch theoretical scientist [[Johannes Diderik van der Waals]] demonstrated that these gases could be liquefied, but only under conditions of very high pressure and very low temperatures. In 1877, [[Louis Paul Cailletet]] in France and [[Raoul Pictet]] in Switzerland succeeded in producing the first droplets of [[liquid air]] at {{convert|-195|C|F K}}. This was followed in 1883 by the production of liquid oxygen {{convert|-218|C|F K}} by the Polish professors [[Zygmunt Wróblewski]] and [[Karol Olszewski]].

Scottish chemist and physicist [[James Dewar]] and Dutch physicist [[Heike Kamerlingh Onnes]] took on the challenge to liquefy the remaining gases, hydrogen and [[helium]]. In 1898, after 20 years of effort, Dewar was the first to liquefy hydrogen, reaching a new low-temperature record of {{convert|-252|C|F K}}. However, Kamerlingh Onnes, his rival, was the first to liquefy helium, in 1908, using several precooling stages and the [[Hampson–Linde cycle]]. He lowered the temperature to the boiling point of helium {{convert|-269|C|F K}}. By reducing the pressure of the liquid helium, he achieved an even lower temperature, near 1.5 K. These were the [[Lowest temperature recorded on Earth|coldest temperatures achieved on Earth]] at the time and his achievement earned him the [[Nobel Prize]] in 1913.<ref name="nobel">{{Cite web |title=The Nobel Prize in Physics 1913: Heike Kamerlingh Onnes |url=https://www.nobelprize.org/nobel_prizes/physics/laureates/1913/onnes-bio.html |access-date=24 April 2012 |publisher=Nobel Media AB}}</ref> Kamerlingh Onnes would continue to study the properties of materials at temperatures near absolute zero, describing [[superconductivity]] and [[superfluids]] for the first time.