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Does anybody know how long it takes water to freeze?
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The colder the air is around it, the faster it will freeze. A huge tub of water will take longer to freeze than a glass of water.
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Unasked.com Answerer Milander wrote a great article I would like to share with you...
I started with three identical glass containers, each holding 100ml (about 3.5 fl. oz.) of filtered water: one at room temperature (72?F/22?C), one at the same temperature as my hot water tap (115?F/46?C), and one boiling (212?F/100?C). I put all these into my freezer, which has an air temperature of 0?F (?18?C). Since I knew that the water would not turn from liquid to ice all at once, my arbitrary standard for frozenness was the time at which a wooden chopstick dropped into the center of the container would no longer touch the bottom. I checked each of the containers every 5 minutes. The results? The room-temperature water froze in 50 minutes. The hot water froze in 80 minutes. And the boiling water froze in 95 minutes. My verdict: no contest?not even remotely close. Given the conditions in my freezer and the water I used, I could not reproduce the Mpemba effect.
I also tried a container of previously boiled water, now at room temperature. It froze in 60 minutes?more time (not less) than the unboiled water had taken, but not by much.
http://itotd.com/articles/521/water-freezing-and-boiling-myths/
Related to this is the question of whether hot water freezes faster than cold water.......
All things being equal, cold water freezes faster.
It takes time for the energy contained in a hot object to be transferred to a cold object. However, the rate of heat transfer is proportional to the temperature difference between the two objects, so hot water will lose heat faster than cold water. In other words, if you have water at 90 degrees C and water at 10 degrees C and the freezer is at -10 degrees C, the hot water will lose heat five times faster than the cold water; however, the cold water will still win the race. As the hot water cools it's rate of heat transfer will decrease, so it will never catch up to the cold water.
Some people claim that hot water freezes faster because a pot of boiling water can be thrown into the air on a cold winter day, and it freezes in mid air creating a shower of ice crystals. Whereas a pot of cold water thrown into the air comes down as large blobs of water. This happens because the hot water is so close to being steam, that the act of throwing it into the air causes it to break up into tiny droplets. (hot water is less viscous than cold water, listen to the sound it makes when you pour it in the sink) The small water droplets have a large surface area which allows for a great deal of evaporation, this removes heat quickly. And finally, the cooled droplets are so small, that they can be easily frozen by the winter air. All of this happens before the water hits the ground. Cold water is thicker and stickier, it doesn't break up into such small pieces when thrown into the air, so it comes down in large blobs. '
Answered by: Joe Larsen, Ph.D. Chemistry, Rockwell Science Center, Los Angeles, CA
source http://www.physlink.com/education/AskExperts/ae7.cfm
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Just to recap the steaming hot water freezing faster than cold water again - ...
Now logic would suggest that the hot water would take longest, and it's true but to a point. The steam from hot water will freeze before the cold water, it's amazing, the facts now have hot steaming water freeze before cold water does.
But this won't occur if the hot water is just sitting there beside cold water, the hot water will need to cool before it freezes and catch up to cold water - Which is about a 20 minute difference.