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how to supercool water?

the numberous videos of water freezing almost instantly. but how is it done? i mean theres no chemicals in the videos as far as i can tell.

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kelseymh7 years ago
Supercooling requires lowering the temperature of a waterbath slowly and uniformly, with no disturbances and no impurities which can seed crystal nucleation. 

Use a very clean glass (Pyrex) bowl -- wash it by hand with detergent and water, rinse with distilled water, and wipe with a clean lint-free rag.  Finally, rinse and wipe again with clean isopropyl alcohol, and allow to air dry covered with waxed paper.

Fill the bowl with distilled water, and put into your freezer (covered with waxed paper) overnight.  Don't go check on it, and if possible don't do anything else in the freezer during that time.  If you bump the bowl, you're likely to cause nucleation.

If things go successfully, you should have a bowl of still-liquid water in your freezer in the morning.  Tap the side with a spoon, or drop a marble into it, and the whole thing should freeze through in a couple of seconds.
Would distilled work or would you need deionized water?
 
 Can't you just put a cup in the microwave and then into the freezer that way you get it really clean because you have boiled it in the same container as you are going to use in the freezer?
.  From what I have read, distilled water works best, but that may just be a lack of dissolved gasses. Boiling may do the trick. DI should work well, also. IIRC, cleanliness is the biggest factor.
.  As with kelseymh, I have no first-hand experience. YMMV.
I might be thinking of something else, but I thought supercooling water was important in making blocks of ice for ice sculpture and that they used deionized water so it was very, very clear once frozen.

Thoughts?
 
http://en.wikipedia.org/wiki/Ice_sculpture#Raw_material
"Clear ice is mostly the result of slow freezing that allows impurities to escape." (my emphasis)
Memory is such a fickle thing.
 
I don't think you need to go deionized.  I have read of supercooling being done with straight tap water, but don't have personal experience with that. 
d2j5 (author)  kelseymh7 years ago
cool!
AndyGadget d2j57 years ago
Super-cool . . . Click the 'best answer' button, d2j5.
d2j5 (author)  AndyGadget7 years ago
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