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From: dgary@ecsvax.UUCP (D Gary Grady)
Newsgroups: net.physics
Subject: Re: Re: freezing hot water
Message-ID: <1386@ecsvax.UUCP>
Date: Mon, 3-Jun-85 17:12:53 EDT
Article-I.D.: ecsvax.1386
Posted: Mon Jun  3 17:12:53 1985
Date-Received: Thu, 6-Jun-85 20:41:38 EDT
References: <188@sdcarl.UUCP> <186@rruxo.UUCP> <1158@sjuvax.UUCP>, <620@digi-g.UUCP>
Organization: Duke U Comp Ctr
Lines: 24

Jearl Walker, the same Flying Circus of Physics guy who did the
firewalking, also argued with his mother over the question of hot water
freezing faster than cold.  He told her about Newton's Law of Cooling
and so on, and to prove to her that hot water would not freeze faster
than cold, he did an experiment, which sure enough verified Newton's
Zeroth Law: Mom Was Right.

No explanation here.  Walker has reported some tests involving covering
the tops of the containers that suggest evaporation is somehow involved.
Others who have speculated on this suspect convection currents...

So much for old spouse's tales always being wrong.  By the way, a
popular old physicist's tale that turns out to be baloney is that water
in a sink or bathtub spirals down the drain in a direction determined by
the Coriolis force (e.g., counterclockwise in the Northern Hemisphere).
The Coriolis force is far too weak, even when tests have been conducted
in circular vats in which the water is allowed to settle for many days
before emptying.  (Curiously, the direction of spiral tends to reverse
when the water surface gets down to about 5cm from the bottom...)
-- 
D Gary Grady
Duke U Comp Center, Durham, NC  27706
(919) 684-3695
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