title: When water does not boil at the boiling point.
abstract: Every schoolchild learns that, under standard pressure, pure water always boils at 100 degrees C. Except that it does not. By the late 18th century, pioneering scientists had already discovered great variations in the boiling temperature of water under fixed pressure. So, why have most of us been taught that the boiling point of water is constant? And, if it is not constant, how can it be used as a 'fixed point' for the calibration of thermometers? History of science has the answers.
authors.affiliation: Department of Science and Technology Studies, University College London, Gower Street, London WC1E 6BT, UK. h.chang@ucl.ac.uk
authors.forename: Hasok
authors.initials: H
authors.lastname: Chang
mesh_terms: D002138:Calibration; D004739:England; D005602:France; D049671:History, 18th Century; D049672:History, 19th Century; D006358:Hot Temperature; D006801:Humans; D010825:Physics / Q000266:history*; D012108:Research Personnel / Q000266:history; D012606:Scotland; D013821:Thermometers / Q000266:history*; D044366:Transition Temperature; D014867:Water / Q000737:chemistry*
chemical_list: D014867:Water