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From: bobm@rtech.ARPA (Bob Mcqueer)
Newsgroups: net.cooks
Subject: Re: Re: freezing hot water
Message-ID: <407@rtech.ARPA>
Date: Mon, 20-May-85 17:22:54 EDT
Article-I.D.: rtech.407
Posted: Mon May 20 17:22:54 1985
Date-Received: Fri, 24-May-85 04:16:46 EDT
References: <442@leadsv.UUCP>
Organization: Relational Technology, Berkeley CA
Lines: 33

> In article <188@sdcarl.UUCP>, rusty@sdcarl.UUCP (rusty c. wright) writes:
>> one thing that i've always had trouble believing is the common
>> belief that if you use hot water for making ice cubes that they
>> will freeze faster.  does anybody have any idea why they should
>> do that?
> 
> I've been silent until now, but I can't take it any longer.  Rusty, who
> writes above, should be skeptical.  Asserting that hot water freezes
> faster than cold is a direct violation of the second law of thermodynamics.
> Asserting that cold water boils faster than hot is also a violation.

Oh boy, this one again.  If we're going to have a prolonged discussion
it belongs in net.physics, but I might as well say my piece.  The "folk
tale" here can be construed to be true, and nobody is violating the second
law of thermodynamics.  Remember evaporation.  Nobody said you had to wind
up with equal amounts of ice from equal amounts of water.  The first time I
heard this discussion I did a few experiments in my freezer, and sure enough,
if you use shallow enough containers you can get warmer water to yield ice
faster, and quite noticably LESS ice.  I would also note that I was doing
this in Colorado (dry climate), had to use shallower containers than the
standard ice cub tray to obtain the effect, and didn't find that it was by
much of a margin.

Thing with "folk tale" type statements like this - they aren't carefully
stated, and very often some secondary effect normally not considered in
a "pure" theoretical model (and carefully screened from any controlled
experiments designed to test the model) is being observed.  If we want to
extend this to a discussion of firewalking, experiment vs. theory, models
vs. the real world, etc., let's move it elsewhere, and let people trade
recipes in peace :-).

Bob McQueer
amdahl!rtech!bobm