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From: vch@rruxo.UUCP (V. Hatem)
Newsgroups: net.cooks
Subject: Re: freezing hot water
Message-ID: <186@rruxo.UUCP>
Date: Fri, 17-May-85 15:30:50 EDT
Article-I.D.: rruxo.186
Posted: Fri May 17 15:30:50 1985
Date-Received: Sat, 18-May-85 01:43:32 EDT
References: <188@sdcarl.UUCP>
Organization: Bell Communications Research, Piscataway N.J.
Lines: 42

For God's sake, you *can't* freeze hot water faster than cold water! 
(for the same reason you *can't* boil cold water faster!)

AGAIN:

	Newtons (thrid, I think) Law of Thermodynamics!

which, stated roughly, says that an object (substance or whatever) that has
mass cools (heats) in direct proportion to it's mass and the difference
between the desired temps.

i.e.: a large glass of cool water, when heated, has to increase in temp
until 212 degrees is attained. The same mass of hot water has a FEWER
number of degrees to increase. Freezing is the same way. The mass has to 
give off a good deal of heat (ie the surroundings must ABSORB a good deal
of heat) in order to freeze hot water. 

The mass will actually give off a greater amount of heat when hot, but when
the formerly hot water becomes the same temp as the cool water, the 
speed in which it gives off the heat is decreased (that's where the difference
between the temps comes in) and is actually the same rate as a fresh glass of
water from the tap with the same temp! (in other words, you just wasted time
cooling the hot water to tap-temperature)

If you have any doubts, mail me - if I get enough replys, I'll look up
the formulas in my old chemistry book and post it.


Vince Hatem
Bell Communications Research
rruxo!vch

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