Editing Flash freezing (section)

== Applications and techniques ==
[[File:Cryopreservation.jpg|thumb|Flash freezing being used for [[cryopreservation]]]]

Flash freezing is used in the [[food industry]] to quickly freeze [[perishable food]] items (see [[frozen food]]). In this case, food items are subjected to temperatures well below{{clarify|What temperature? All freezers work well below freezing point but items put in it don't flash freeze|date=February 2017}} the [[freezing point|freezing point of water]]. Thus, smaller ice crystals are formed, causing less damage to [[cell membranes]].<ref>Da-Wen Sun (2001), Advances in food refrigeration, Yen-Con Hung, Cryogenic Refrigeration, p.318, Leatherhead Food Research Association Publishing, http://www.worldcat.org/title/advances-in-food-refrigeration/oclc/48154735</ref> American inventor [[Clarence Birdseye]] developed the "quick-freezing" process of [[food preservation]] in the 20th century using a cryogenic process.<ref>[https://books.google.com/books?id=UigDAAAAMBAJ&dq=1930+plane+%22Popular&pg=PA26 "Quick-Frozen Food Exactly Like Fresh."] ''Popular Science Monthly'', September 1930, pp. 26-27.</ref> In practice, a mechanical freezing process is usually used instead due to cost. There has been continuous optimization of the freezing rate in mechanical freezing to minimize ice crystal size.<ref name="FAO" />

Flash freezing techniques are also used to freeze biological samples quickly so that large ice crystals cannot form and damage the sample.<ref>{{cite web |title=Freezing Tissue |url=http://www.biotech.ufl.edu/EM/data/freeze.html |archive-url=https://web.archive.org/web/20120111233417/http://www.biotech.ufl.edu/EM/data/freeze.html |archive-date=11 January 2012 |access-date=2009-07-03 |publisher=Biotech.ufl.edu}}</ref> This is done by submerging the sample in [[liquid nitrogen]] or a mixture of [[dry ice]] and [[ethanol]].<ref>{{cite web |title=Preparing Competent E. coli with RF1/RF2 solutions |url=http://www.personal.psu.edu/dsg11/labmanual/DNA_manipulations/Comp_bact_by_RF1_RF2.htm |url-status=dead |archive-url=https://web.archive.org/web/20210923024451/http://www.personal.psu.edu/dsg11/labmanual/DNA_manipulations/Comp_bact_by_RF1_RF2.htm |archive-date=2021-09-23 |access-date=2009-07-03 |publisher=Personal.psu.edu}}</ref>

Flash freezing is of great importance in [[atmospheric science]], as its study is necessary for a proper [[climate model]] for the formation of [[ice cloud]]s in the upper [[troposphere]], which effectively scatter incoming [[solar radiation]] and prevent Earth from becoming overheated by the Sun.<ref name=":2">{{Cite web |title=Better understanding of water's freezing behavior at nanoscale |url=https://www.sciencedaily.com/releases/2013/05/130521152429.htm |access-date=2017-01-17 |website=sciencedaily.com}}</ref> The results have important implications in [[climate control]] research. One of the current debates is whether the formation of ice occurs near the surface or within the [[micrometre]]-sized droplets suspended in clouds. If it is the former, effective engineering approaches may exist to tune the [[Surface tension|surface tension of water]] so that the ice crystallization rate can be controlled.<ref name=":2" />