Ben Ramseyramsey
Dec 14, 2025, 6:20 PMScience teachers in middle school taught me that glass is a liquid, but today, I learned that is a myth.
Glass does not flow. “The sags and ripples observed in old glass were already there the day it was made.”
Replies
- Ben RamseyramseyDec 14, 2025, 6:21 PM
In 2017, a study computed the rate of flow of the medieval glass in Westminster Abbey, and they “calculated that the maximum flow rate of medieval glass is 1 nm per billion years, making it impossible to observe in a human timescale.”
- Ben RamseyramseyDec 14, 2025, 6:25 PM
Most solids have a crystalline structure at the molecular level. The molecules form a rigid, repeating pattern. Glass does not have this property. It is amorphous; the molecules have no defined arrangement.
Alerta! Alerta!heiglandreasDec 14, 2025, 6:41 PM@ramsey Which is ... somehow ... the state in a liquid...
BTW: Crystaline structure like in ionic bonding is not always found in solids. There is also Metalic bonding https://en.wikipedia.org/wiki/Metallic_bonding
- Ben RamseyramseyDec 14, 2025, 6:42 PM
@heiglandreas Technically, I guess glass *does* flow, but it’s over billions of years.
- Alerta! Alerta!heiglandreasDec 14, 2025, 6:44 PM
@ramsey Yeah! That's probably more the timescale...
Dec 14, 2025, 9:26 PM@ramsey So what you are saying is … glass is a liquid 🤪
- Ben RamseyramseyDec 14, 2025, 11:14 PM
@michael It’s an amorphous solid.
Dec 14, 2025, 7:20 PM@ramsey while this is dissapointing, have you seen the pitch drop experiment?
The Sleight Doctor 🃏🍉ApostateEnglishman@mastodon.worldDec 14, 2025, 6:37 PM@ramsey Due to it's disordered molecular structure, glass is best described as an amorphous solid. It does behave somewhat like a viscous liquid, so it's *theoretically* possible we could shoot a time lapse of glass succumbing to gravity and appearing to "melt", but it would take billions, not hundreds of years to film it!
- Ben RamseyramseyDec 14, 2025, 6:39 PM
@ApostateEnglishman Yep. That Wikipedia article describes a study they did of the glass in Westminster Abbey. https://phpc.social/@ramsey/115719308220159459
Maxmax@toet.dnzm.nlDec 14, 2025, 7:17 PM@ramsey Huh, TIL.
Ross McKaywebaware@fosstodon.orgDec 14, 2025, 10:32 PM@ramsey I had a high school art teacher once who insisted that glass was a liquid and that was why you saw ripples. He got very angry when I said it was rolled glass that unevenly refracted light, in fact so furious he slammed his stick down hard on his desk and shouted "it's a liquid!"
Wasn't a very good art teacher, in various ways really.