The spontaneous crystallization of supercooled water

✍ Scribed by B. J. Mason

• Publisher: John Wiley and Sons
• Year: 1952
• Tongue: English
• Weight: 426 KB
• Volume: 78
• Category: Article
• ISSN: 0035-9009
• DOI: 10.1002/qj.49707833503

✦ Synopsis

Abstract

It is shown theoretically that the rate of nucleation of the ice phase in supercooled water changes very rapidly with temperature in the neighbourhood of −40°C. Thus, in chilling a supercooled water cloud below this temperature one would expect to observe a rapid increase in the number of ice crystals which appear as the temperature falls. This is verified by observations made in a cold chamber. The different critical temperatures for the spontaneous appearance of ice crystals quoted by Schaefer (−39°) and the Oxford workers (−41°C) probably arise as the result of differences in the experimental conditions. It is tentatively suggested that the parts of mother‐of‐pearl clouds showing iridescence at temperatures around −80°C consist of spheres of ‘glassy’ ice, which may eventually crystallize spontaneously to form ice crystals towards the leeward edges of the cloud.