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Q & A: freezing really pure water

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Most recent answer: 04/20/2015
Q:
Can water freeze if there is absolutely no impuritiesEx. (dirt, minerals, bacteria)
- Manny (age 17)
beaver, pa, beaver
A:

Nice question. You're wondering whether the water can stay supercooled, as we discuss here: https://van.physics.illinois.edu/qa/listing.php?id=1618. Very pure water can stay well below 0°C for a long time without freezing, especially if it's in a little isolated drop so there's no container to help start the freezing. Below about -37°C, however, it will rapidly freeze without any help. (https://en.wikipedia.org/wiki/Ice_nucleus) That's called the temperature of homogeneous nucleation.

Mike W.


(published on 04/20/2015)

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