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From: hopp@nbs-amrf.UUCP (Ted Hopp)
Newsgroups: net.puzzle,net.math
Subject: Re: Re: Polar Bear Problem Sequel
Message-ID: <42@nbs-amrf.UUCP>
Date: Mon, 28-Oct-85 20:49:30 EST
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Posted: Mon Oct 28 20:49:30 1985
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Xref: linus net.puzzle:1027 net.math:2084

> By the way: heat causes metal to expand.  If you have a piece of metal
> with a spherical hole in it, does the hole expand, contract, or remain
> the same when the metal is heated?  What about a square hole?  I don't
> know the answer!
> 
> ...ranjit bhatnagar

If you heat the metal enough, it will glow.   The hole will then be a
black hole, and therefore contract forever.

Oh, I'm sorry.  I thought we were in net.physics.newman ;-)

Actually, the hole (spherical, square, circular, or whatever) will
expand.  Imagine heating the metal that filled the hole when the metal
was cool while you are heating the metal with the hole.  The "filler"
will fit back into the hole when both are hot.  Since the filler
chunk expanded (being metal), the hole must have expanded.  As to
why the filler should fit back in, imagine heating the metal plus
filler without separating the filler - if it isn't going to fit in
when heated separately, why does it exactly fill where the hole would
have been?

-- 

Ted Hopp	{seismo,umcp-cs}!nbs-amrf!hopp