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From: matt@oddjob.UUCP (Matt Crawford)
Newsgroups: net.physics
Subject: Re: A thought experiment on freezing water
Message-ID: <765@oddjob.UUCP>
Date: Thu, 30-May-85 22:00:04 EDT
Article-I.D.: oddjob.765
Posted: Thu May 30 22:00:04 1985
Date-Received: Fri, 31-May-85 06:28:03 EDT
References: <455@leadsv.UUCP>
Reply-To: matt@oddjob.UUCP (Matt Crawford)
Distribution: na
Organization: U. Chicago, Astronomy & Astrophysics
Lines: 25
Keywords: water,cooling,heat

In article <455@leadsv.UUCP> morse@leadsv.UUCP (Terry Morse) writes:
>There has been a discussion in net.cooks (of all places) of whether
>or not it is possible to freeze hot water faster than cold water, all else
>being equal.
>
>There have been several explanations as to why it might happen. ....

(This is an excelent argument for increased funding of science
instruction at the elementary school level.)

Assumption:  The temperature of an object never takes a sudden jump,
it varies continuously, although in some cases the change is rapid.

Then consider two samples of water, one hot and one cold.
At some time the hot sample will cool down to the initial
temperature of the cold water.  How will it then freeze 
faster than the cold water?  You might argue that some of
the hot water will have evaporated and that under some con-
ditions the initially hot water could then freeze faster
due to its lesser volume, but then I will say that "a given
size ice cube can never be formed more quickly from hot
water than from cold."
_____________________________________________________
Matt		University	crawford@anl-mcs.arpa
Crawford	of Chicago	ihnp4!oddjob!matt