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shellac

> glass is a particular type of liquid ...

No, it's not a liquid.

> ... so its internal structure is all a jumble

That's true. But it doesn't flow, which is a rather significant part of being liquid.

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Went on a double date with another guy who was a PhD chemist. He made an offhanded remark about glass being a liquid, and trotted out that saw about ancient cathedral windows being thicker at the bottom.

I explained that that was actually untrue, and explained the crown glass method, and that a small percentage of those panes are thicker at the top. He just gave me this scornful glance and said "I've got a doctorate in chemistry, I think I know a little bit more about this than you do." I was so mad! No, dingus, you don't. You study membranes, and you've never read anything about glass. But I didn't want to start a fight, so I had to just let it go.

I remember being taught that glass was a liquid in high school (early 90s) and they referenced antique glass being thicker at the bottom as an example. So I was fascinated by that and thought it was true for the longest time. :/

Some interesting reading regarding that urban myth and the actual science:

http://dwb.unl.edu/Teacher/NSF/C01/C01Links/www.ualberta.ca/...

That's interesting. I was also taught glass is a liquid.

We should correct people when they say it's a liquid OR a solid, because neither is correct; but I think we should not be so critical/furious if someone calls glass a supercooled liquid, etc. (ref: Tamman "frozen super-cooled liquid", the article: "a particular type of liquid").

Calling it an "amorphous solid" is obviously the currently accepted formal physicist category of course.

The (scientist approved) test for determining basic matter phases is very rudimentary. Put the object/quantity in question in a can. Does it fill the whole space of the can, no matter what size can you use? Then it's a gas. Does it fill just the bottom of the can? Then it's a liquid. Does it instead retain its shape? Then it's a solid.

The urban legend says that it's like pitch; if you put it in the can, it will slowly fill the bottom of the can, but it will take many centuries since it flows so slowly.

This is not true, but it means your test would not convince anybody of anything.

It should be convincing, because the test specifies a time limit in the range of a couple of minutes.

That's really a no-win argument. There's really nothing to gain, and you run the risk of looking like a jerk who has to correct everyone and can't accept being wrong in front of your date. Letting it go is the best answer, IMO.

I interpreted that as they meant "amorphous solid" because they said it was not crystalline. But calling it a liquid if that's what they meant is a bit...wrong.

there is physics and there is language (and sometimes the twain shall meet). does normal glass flow at room temperature and typical earth gravity? nah. do glasses flow at some temperatures? who would deny it? so glasses are possessed of liquid properties. your non-crystalline statement is the properly important one (in my humble opinion), and it essentially defines what a glass is. and as a sibling commenter here states the thicker glass in panes in old buildings is probably a statistical phenomenon, or just possibly represents a glazer's choice, rather than anything to do with chemistry or physics or holders of phds, (by the bye, from experience, if a phd requires you to add a "Dr" to their name, that's a pretty good test of jerkhood (jerkship?))

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