Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10.1 6/24/83; site mit-eddie.UUCP
Path: utzoo!linus!philabs!cmcl2!harvard!think!mit-eddie!jbs
From: jbs@mit-eddie.UUCP (Jeff Siegal)
Newsgroups: net.puzzle,net.math
Subject: Re: Re: Polar Bear Problem Sequel
Message-ID: <294@mit-eddie.UUCP>
Date: Sat, 2-Nov-85 16:10:43 EST
Article-I.D.: mit-eddi.294
Posted: Sat Nov  2 16:10:43 1985
Date-Received: Tue, 5-Nov-85 05:28:11 EST
References: <361@proper.UUCP> <367@faron.UUCP> <10755@ucbvax.ARPA> <42@nbs-amrf.UUCP> <541@ttrdc.UUCP>
Reply-To: jbs@mit-eddie.UUCP (Jeff Siegal)
Distribution: net
Organization: MIT, Cambridge, MA
Lines: 19
Xref: linus net.puzzle:1054 net.math:2105

In article <541@ttrdc.UUCP> levy@ttrdc.UUCP (Daniel R. Levy) writes:
>...with ordinary glass when it is heated, often resulting in
>shattering [BTW, can anyone tell why it is that ordinary glass will
>break when heated, but the same glass was successfully cooled into that
>shape from a molten blob or sheet?].)  Anyhow, some glasses, like Pyrex,
>are much less subject to this since they expand much less when heated than
>ordinary glass.  The internal forces would constrain the "filler" piece
>of material to be a slightly different shape when an integral part of the
>whole than if heated by itself.  Just ramblin' on...

The glass doesn't shatter becuase from expansion, but rather, from
_uneven_ expansion.  If the glass is heated sufficiently evenly or
sufficiently slowly (so the heat is conducted throughout the glass),
it will not shatter.

Thermal expansion really is like a photo-reducing and photo-increasing
copy machine, only one that works in three dimensions.

Jeff Siegal - MIT EECS