Re: (OT) Re: A89: What's Wrong?
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Re: (OT) Re: A89: What's Wrong?
Darnit, I was hoping I wouldn't have to actually do this
research again. After all, there's no money in it for me
this time. Glass is an amorphous noncrystaline solid.
This is easily apparent by simple observation. All
substances that do not degrade (I.E., by burning) into
other substances first exist in exactly one of three
states (plus plasma, which only affects their
chemical reaction properties). Though some liquids
change viscosity as temperature changes, there is
a clear change from liquid to solid, and no instant
change anywhere in the liquid state. Glass, as
liquid, is quite viscous and easy to pour. And it
freezes similarly to ice (except that it sinks in
liquid glass, and that there is only a very slight
density and volume change (though the thermal
expansivity, heat capacity, and viscosity do change
suddenly when it changes states)). And, no matter
how much cooler you make glass, it never changes
state again.
And if you want more proof, here are the first
three pages Jeeves gave me.
http://www.ualberta.ca/~bderksen/florin.html
http://www.weburbia.com/physics/glass.html
http://www.spectrumglass.com/Library/ScoreArticles/BitAboutGlass.html
In a message dated 1/26/01 2:59:44 PM US Mountain Standard Time,
noveck@pluto.njcc.com writes:
> I hate to post offtopic, but I hate to let incorrect posts go by even
> more -- so to prevent any more myths from spreading, let me correct some of
> these points:
>
> > Glass is a solid that behaves like a liquid. I don't know if that's what
> > TGaArdvark means or not but, I think it is. It's why, if you see some
old
> > glass, it'll be thicker at the bottom of the pane and thiner towards the
> > top.
>
> No, the original poster -- who stated that glass is an amorphous liquid --
> was correct.
>
> A solid, by definition, consists of a rigid, crystalized unit -- it has a
> clear structure that is repeated over and over again throughout the
> substance.
>
> Glass, on the other hand, is not crystalized, and, in fact, is not a solid
-
> it's a liquid. More specifically, it's an "amorphous" liquid: one that
> appears solid and that does not _appear_ to flow. Since it does not have
> the rigid crystal structure, glass _will_ flow -- but this process takes
> _millions_ of years. See more below:
>
> > > that the stained glass windows of some medieval churches seem to
> > > "run"...
> >
> > I believe that's so... But, I'm not positive. I'm near positive. I
hope
> > my extremely limited knowledge helped you out in some form or fashion...
>
> According to my (up-to-date) chemistry book, glass _will_, flow; _however_,
> this will take millions of years. No man-made glass has been around long
> enough to exhibit any _noticeable_ change in appearance. Rather, as
another
> poster already stated, the reason that medieval glass windows are thicker
at
> the bottom is much simpler: due to imperfections in the glass-making
> process, medieval glass was typically thicker on the bottom than on the
top.
> The builders, exhibiting common sense, put the thicker end on the bottom.
> Thus, although the glass may appear thicker on the bottom today, that's
> exactly how they saw it hundreds of years ago when the glass was created.
>
> Since the myth that this thickness is caused by flow is so widespread, I
> wouldn't take any of this on any one person's authority -- just go find a
> modern chemistry book, search the index for amorphous, and you'll probably
> find something very similar to the above paragraph nearby.
>
> -Scott