Is Glass A Solid Or An Extremely Slow Moving Liquid?

It seems solid to me, but to a physicist this is a valid question. Glass is one of the
"squishy" substances that cannot be pinned down as a solid or liquid. Referred to as "soft condensed materials," they include everyday substances such as toothpaste, peanut butter, shaving cream, plastic and glass.

As water cools to its freezing point, it crystallizes into ice. When glass cools from a hot liquid, it slows down but never crystallizes. Researchers at Emory University have studied the phenomenon for years, but have yet to find a definitive answer, which could greatly impact the science of nanotechnology. Link

Newest 5
Newest 5 Comments

Yes old thread and old question.
Glass is not a liquid at comfortable human temperatures.
The often cited wavey glass pane windows and bluges i the panes are falicies.
Look closely at an old pane of glass that is supposedly melting. Sometimes the thickest points are the sides or top of the pane. This discounts that glass is liquid and boing pulled down by gravity. Unless of course it was mounted in one of those obsolite anti-gravity window frames.

The ones that are thickest at the bottom should show the glass melting onto and starting to wrap around or puddling up on the windows frame or stained glass lead framing. Yet it does not!

Glass panes that are a few centuries old should be paper thin at the top and all puddled up at the bottom by now, but are not.

Glass pane munufacturing was not perfected and commericalized until the late 1950s. Any glass panes you see from before then will have many optical imperfections that are noticeable when looking through them.
Abusive comment hidden. (Show it anyway.)
Bah. Science teachers were teaching this junk decades ago when I went to school (the same time they taught us the earth was cooling and their was an ice age fast on the way ... make up your minds!) and it was disproved then. In the late 80s my Materials Science prof in college chuckled over the common misconception of waviness from window glass flowing in old buildings.

Ignorant, lazy teachers continue to spout such absurdities, but with the easy access of information we have today, it's unforgivable. No excuses for lazy deadwood teachers! Pay the good ones more and fire the rest. Take that useless Masters of Education degree and go flip burgers. If you were any good, you would have gotten a real Masters in (choose one) science, history, math, etc.
Abusive comment hidden. (Show it anyway.)
I had to chuckle about Floyd's high school science teacher comments. Yes, a lot of really bad information comes from teachers who are nitwits and speak from their butts. Don't get me wrong, an awesome teacher (and I've had some) really make a huge difference in kids' lives. The problem is those awesome ones (in the U.S. anyhow) don't get paid any more than the urban legend spreaders. It wouldn't be "fair" after all... Ugh. :-P

Some folks are bringing up the scale of time we are considering. Well the argument is made that glass in 200 year old buildings (like my house) has flowed under the force of gravity. That is the timescale. To be safe, take it out 1000 years or so and look at some old cathedral window glass. It would be pretty tough to find any examples of installed window glass older than that, so speaking of flow rates in geologic timeframes is extrapolating WAY beyond the limits of available samples. The assertion is that glass is visibly thicker in the bottom of old windows because of flow. That has been proven false by gifted material scientists. Any visible waviness was an artifact of production techniques. Done.
Abusive comment hidden. (Show it anyway.)
The key is what time frame are you considering? As said before, if it is geologic time, say millions of years, then glass flow is not unreasonable. However, on short time frames, human lifetime (tens of years), or even human civilization timeframe (hundreds of years), i would bet that the glass flow is negligible.
I'm not sure if the amorphous nature of pitch is the same as glass, but take a look at:
Abusive comment hidden. (Show it anyway.)
Login to comment.

Email This Post to a Friend
"Is Glass A Solid Or An Extremely Slow Moving Liquid?"

Separate multiple emails with a comma. Limit 5.


Success! Your email has been sent!

close window

This website uses cookies.

This website uses cookies to improve user experience. By using this website you consent to all cookies in accordance with our Privacy Policy.

I agree
Learn More