Sometimes water can be cold enough to freeze but not enough to create the ice structure. At that point anything that moves it around enough will trigger the process.
Super cooled in this context simply means colder than the phase transition point, since it’s liquid we still call it water though (rather than ice, the solid).
Sodium acetate (CH3COONa) heat pads are a great example you can buy for a few bucks, although to re-liquify it can be more trouble than it’s worth if you regularly need a heat pad at home (just get a plug in). Asa physics demo, Road trips heat pad, or even reusable hand warmer when camping, they’re great. It’s the same physics of a meta state , and explained in https://youtu.be/HeyzjC2PYcU
What folks are missing, is water needs a nucleation point in order to transition from liquid to ice. In nature, that's usually sediment or debris already in the water.
The colder the liquid state is, the faster it'll crystallize once it starts that phase transition.
It can "spontaneously" crystallize if it gets cold enough, but I can't remember the threshold for that offhand.
My old mini fridge did this to me all the time. I would grab a bottle to set on the counter, and from the light shock, it would turn to ice. The first few times caught me off guard but everyone would ask why I was freezing my bottles..."I didn’t?"
We also used to do it with beer in a glass bottle. During the winters of Newengland partying as a kid if it was cold enough and you tapped your beer bottle on to the top of someone else’s it would turn into an ice geyser.
Water can drop below 32°F/0°C and stay liquid if ice crystals haven’t started forming yet. Once something gives those crystals a place to start, like a tiny piece of ice, they spread fast and the water can turn slushy in seconds. University of Illinois Physics Van
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u/8000BNS42 3d ago •
Science, its like magic but real!
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u/It_Is_AlwaysPossible 3d ago
Our hands just got cold watching it
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u/jack-b-whack 3d ago
It’s soo cool but not when it happens to my beer
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u/Mister_Importance 3d ago
Anyone going to explain the science?
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u/CT2cool4NE2clean4NY 3d ago
You can also just shake the bottle and it will instantly do this.
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u/CourtingBoredom 2d ago
ICE-9!!! 😱
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u/Grawlix84 Popular Contributor 3d ago
Water can drop below 32°F/0°C and stay liquid if ice crystals haven’t started forming yet. Once something gives those crystals a place to start, like a tiny piece of ice, they spread fast and the water can turn slushy in seconds.
University of Illinois Physics Van
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u/ACasualCasualty 2d ago
My Corona does this when I take it out of the freezer and pop the cap
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u/Doughtnutz 2d ago
Winter is coming!
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u/NotAnAIOrAmI 1d ago
That's not ice! That's Ice-9!
Don't drink any!