2006-09-05 09:33:06 · 12 answers · asked by David T 3 in Science & Mathematics ➔ Physics
Every one says not, but has anyone tried it?
2006-09-05 23:07:56 · update #1
The Mpemba Effect
Click the link for an explanation
http://math.ucr.edu/home/baez/physics/General/hot_water.html
And here
http://www.school-for-champions.com/science/mpemba.htm
2006-09-05 09:36:25 · answer #1 · answered by footynutguy 4 · 1⤊ 1⤋
This cannot be true.
It doesn't.
Water freezes at 0 degrees. The hot water has to get down to the temperature of the cold water, then it will be cold water and will take the same time to freeze as the cold water did, all other things being equal.
2006-09-05 18:06:17 · answer #2 · answered by hi_patia 4 · 0⤊ 0⤋
hot water does not freeze quicker than cold water because of the
latent heat,latent heat in this case is the amount of energy required to change the liquid into a solid i.e.2260kJ of heat must lost before a liter of water @100*C will freeze.
2006-09-06 04:57:43 · answer #3 · answered by bryte 3 · 0⤊ 0⤋
Freezing is completely dependant on the temperature of the water and how much heat can be lost per time for the container of liquid in question. (Freezing point depression can be an issue due to air, but it is a VERY small effect. Freezing point depression due to salts is much larger comparativelly.)
This said, if I place 2 bowls of water in my freezer - one at 40 degrees Celcius and one at 4 degrees celcius - the cooler one will freeze ahead of the warm one every time...
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Concerning the link to the Mbepa affect listed in a response above:
The link to this paper makes several factual errors of science. Just one example is his confusion with supercooled fluids and freezing allowing a fluid to freeze ABOVE its normal freezing point. (I have witnessed supercooled water personally. It appears to be normal water, albeit at -20deg celcius, and has ripples upon its surface. Then you give it a sleight shake and it freezes all at once. But again - its supercooled - meaning cooled more than normal.) The author then gives other possible suggestions as to what could cause the freezing of a warm solution ahead of a cool one - convection currents, evaporation, and perhaps most curiously the change of the colution or container from beginning to end of the experiment. This all screams my next point:
Perhaps the best suggestion of what could cause this, however, he skipped -- It was suggested by a high school student in Tanzania. Both "high school student" and "Tanzania" say to me that the science and data was probably suspect or maybe even faked.
2006-09-05 16:39:49 · answer #4 · answered by special-chemical-x 6 · 0⤊ 0⤋
That IS a myth. Hot water does NOT freeze faster than cold.
As others have said, try it yourself and see.
When you get the results come back and let us know what you came up with.
2006-09-05 16:38:11 · answer #5 · answered by Lighthawk Demon 4 · 0⤊ 2⤋
Because it evaporates, leaving less to freeze, and also having the effect of blowing on itself (think blowing on hot soup). Depending on volume and shape of container, cold may well win.
2006-09-05 16:35:41 · answer #6 · answered by kirun 6 · 0⤊ 2⤋
less air in the water.
2006-09-05 16:37:03 · answer #7 · answered by pukaman3000 2 · 1⤊ 0⤋
All the air bubbles are boiled out.
2006-09-05 16:34:55 · answer #8 · answered by American citizen and taxpayer 7 · 1⤊ 0⤋
It does, dont believe anyone that says other wise!
2006-09-05 16:34:53 · answer #9 · answered by Anonymous · 0⤊ 0⤋
some of the impurity's have been boiled out
2006-09-05 16:59:17 · answer #10 · answered by dunlop_tec 3 · 0⤊ 0⤋