Does hot water freeze faster than cold water?

[daveGT]

Great link, Hethj7!!

I posted this after a friend from work swore that is was true, furthermore, he was also told so by a college instructor (?) back in the day, and proceded to conduct his own experiment to confirm the claim. His experiment apparently validated the statement, he claimed. After an informal pole at the office, I found that a solid 50% heard of this and believed it was true, but could not explain why. Then I started thinking about it. Water, like any other liquid has a specific heat. Heating and cooling are reversable, so therefore, based on this logic, cold water will boil faster than warm water. Bla, Bla, Bla, goes my lecture to him, based on my very rusty chemistry and thermodynamics knowledge.

Combining my good common sense and somewhat educated/experienced academic and professional experience, I told him he was nuts, and cold water freezes faster than hot water! Come on man!

I told him his experiment was flawed, not controlled properly, and he drew the wrong conclusions from the results. He conducted the experiment again, using more controls as we discussed, and indeed, the cold water froze quicker.

However, it seems to me that people tend to think that hot water does freeze faster based on personnal real-life experience - except they draw the wrong conclusions.

It turns out we were both wrong (him more than me! LOL!), for hot water will freeze quicker if stored in a highly insulated container (wooden bucket, styrofoam), but it does not freeze quicker just because it is hotter.

Good replys, guys.