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its a proven scientific fact...but nobody knows why. so, why?

2007-01-26 01:43:33 · 13 answers · asked by V3CK!N 1 in Science & Mathematics Physics

13 answers

It doesn't, except under very specific circumstances. It's called the "Mpemba effect". Please see the link for an explanation.

2007-01-26 01:52:05 · answer #1 · answered by . 4 · 1 0

"There are several things that help the hot pail freeze faster than the cold pail. Here are what is thought to be the most significant factors:

The hot water is more likely to be supercooled. This means that the hot water's temperature is more likely to cool to temperatures below zero degrees Celsius. In the cold non-supercooled water, ice crystals form and float to the top, forming a sheet of ice over the top of the water, creating an insulating layer between the cooler air and the water. This ice sheet also stops evaporation. In the hot water that has become supercooled (thus, no longer hot) the water, when it does freeze, freezes throughout, creating more or less of a slush before freezing solid.

Why is hot water more likely to be supercooled? Because hot water is less likely to contain tiny gas bubbles. Gas bubbles form from dissolved gasses as the water cools. When the hot water was heated, these dissolved gasses may have been driven out. In cold water, ice crystals use the tiny bubbles as starting points for formation (in physics, we call them nucleation points). But in the hot water, there are no bubbles, so there aren't as many starting points for the ice crystals."

Google your question and you'll be presented with lots of answers.

2007-01-26 01:52:50 · answer #2 · answered by Dan S 1 · 0 0

It's not a "proven scientific fact". Think about it...the warm water has to become cold water while it's being cooled and that takes extra time.

2007-01-26 01:51:06 · answer #3 · answered by Box815 3 · 0 0

"There are numerous issues that help the nice and cozy pail freeze speedier than the chilly pail. listed under are what's known to be the main important components: the nice and cozy water is extra probable to be supercooled. this suggests that the nice and cozy water's temperature is extra probable to sit down back to temperatures under 0 stages Celsius. contained in the chilly non-supercooled water, ice crystals sort and waft to the remarkable, forming a sheet of ice over the remarkable of the water, coming up an insulating layer between the cooler air and the water. This ice sheet additionally stops evaporation. contained in the nice and cozy water that has grow to be supercooled (subsequently, now no longer warm) the water, while it does freeze, freezes throughout, coming up extra or much less of a slush until eventually now freezing good. Why is warm water extra probable to be supercooled? because of the fact warm water is far less probable to contain tiny gasoline bubbles. gasoline bubbles sort from dissolved gasses because of the fact the water cools. while the nice and cozy water grow to be heated, those dissolved gasses might have been pushed out. In chilly water, ice crystals use the tiny bubbles as commencing factors for formation (in physics, we call them nucleation factors). yet contained in the nice and cozy water, there are no longer any bubbles, so there are not as many commencing factors for the ice crystals." Google your question and you'd be supplied with lots of solutions.

2016-09-28 00:27:35 · answer #4 · answered by carol 4 · 0 0

In general it doesn't.

But in very particular circumstances it does. One theory is that when you put a container of cold water into your freezer, the ice in the freezer insulates the base of the container from the cold, so it freezes slowly.

When you put a container of warm water into your freezer, the ice on the bottom melts, and the water makes a good conducting contact between the container and the base of the freezer. This freezes to solid ice rather than powdery ice, so it is not a good insulator and the water then cools faster and freezes faster.

2007-01-26 02:02:55 · answer #5 · answered by Gnomon 6 · 0 0

Wow...that makes me sad. There's actually two people here who cite a web site written by some moron who's trying to perpetuate this old wive's tale. Warm water does not freeze faster than cold water, ever, period. If you get anything out of this, it's that you can't always believe everything you read, particularly from an unmoderated source like the web. Check references and don't believe things that don't make logical sense, even if some dork with too much time on his hands tries to convince you otherwise.

2007-01-26 02:15:00 · answer #6 · answered by Grizzly B 3 · 0 1

It is only true under certain conditions.
Here is a good discussion.
http://math.ucr.edu/home/baez/physics/General/hot_water.html

If the hot water starts at 99.9° C, and the cold water at 0.01° C, then clearly under those circumstances, the initially cooler water will freeze first. However, under some conditions the initially warmer water will freeze first -- if that happens, it is called the Mpemba effect.

.

2007-01-26 01:53:18 · answer #7 · answered by Jerry P 6 · 1 0

Seems that warm water does not freeze quicker than cold water.

What you're thinking has to do with very hot water, not warm water.

2007-01-26 01:57:05 · answer #8 · answered by Jay 7 · 0 0

it has a lower dew point. also, ever wonder how a lake freezes ? From the bottom up. Just throw a few ice cubes in a glass and notice they are at the top.....ice floats. So in a lake the bottom part of the water is freezing and floating to the top.

2007-01-26 01:52:09 · answer #9 · answered by Anonymous · 0 1

Like h e l l it's a proven scientific fact! It's an old wives' tale, and only gullible dorks believe it!

2007-01-26 01:49:13 · answer #10 · answered by Anonymous · 0 1

warm water is system and freezing temp is surrounding. exchange of energy can be one answer but its not so scientific, the reason is in the fact of molecular density. molecular density o
f warm water or visit www.scientific facts.com

2007-01-26 01:56:36 · answer #11 · answered by RAKESH Y 1 · 0 0

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