Water/Freezing point: Difference between revisions
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imported>Milton Beychok (Added a space to be consistent with all the other temperatures in the table. Is that okay?) |
imported>Chris Day (revert to last version that mentioned it was not measureable) |
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<includeonly> | <includeonly>Not Measurable*</includeonly><noinclude>Not Measurable | ||
Note: The freezing point of water is not | |||
Note: The freezing point of water is not measurable, whereas the melting point is. Very pure water (and we only want to consider pure water in this context) does not freeze without help of a solid crystallization kernel; very cold (metastable) liquid water is obtained by cooling down pure water (I forgot the actual numbers but I have in mind that supercooled liquid water of −40 °C can exist). For some reason (which I don't know) "superheated" ice does not exist, so ice always melts at 0 °C, while the transition from liquid to solid water appears at some fairly random temperatures below zero.--[[User:Paul Wormer|Paul Wormer]] 14:23, 8 February 2010 (UTC) | |||
::The [[supercooling point]] of pure water is around -42 °C under standard conditions, but liquid water can exist even below that temperature, especially at surfaces and in non-pure solutions. --[[User:Daniel Mietchen|Daniel Mietchen]] 15:59, 8 February 2010 (UTC) | |||
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Revision as of 23:59, 10 February 2010
Not Measurable
Note: The freezing point of water is not measurable, whereas the melting point is. Very pure water (and we only want to consider pure water in this context) does not freeze without help of a solid crystallization kernel; very cold (metastable) liquid water is obtained by cooling down pure water (I forgot the actual numbers but I have in mind that supercooled liquid water of −40 °C can exist). For some reason (which I don't know) "superheated" ice does not exist, so ice always melts at 0 °C, while the transition from liquid to solid water appears at some fairly random temperatures below zero.--Paul Wormer 14:23, 8 February 2010 (UTC)
- The supercooling point of pure water is around -42 °C under standard conditions, but liquid water can exist even below that temperature, especially at surfaces and in non-pure solutions. --Daniel Mietchen 15:59, 8 February 2010 (UTC)