I mentioned last week that research from Texas Tech University had finally busted the myth that glass was a liquid. Only, that wasn’t what the research was about at all. As usual, the truth is much less… concrete*.
If I may digress a moment, how many of you were actually taught in school that glass was a liquid? Anybody? I sure wasn’t. My father told me the old window thing and I was promptly laughed at when I brought it up in school. While I love a good old myth-busting, I feel like the whole “liquid glass, saggy window” myth isn’t something the average person encounters in their daily life. I’d be curious to know how prevalent it is outside of trivia circles. Moving on…
In the paper, Jing Zhao, Sindee L. Simon, and Gregory B. McKenna subjected a 20 million year-old piece of amber to tests in order to determine if it had settled into an equilibrium or if it was still flowing. Now, you may be wondering what ancient amber has to do with glass, and this is where the misleading headlines do injustice to the research. Amber and glass belong to the same category of matter called, well, glasses. They’re also called amorphous solids. They’re similar to foams, pastes, concrete, and other non-newtonian fluids in that they do not have the rigid, crystal structures found in metals and other solids, but nor do their molecules flow freely like in a liquid. The researchers wanted to show that amber could be used as viable experimental model.
The issue was never whether glass is a solid or a liquid, because it never fit into the 3rd-grade holy trinity of matter.
What the team at Texas Tech found was that while the amber did settle to equilibrium over the course of 20 million years, it did not change over the few weeks it was experimented on—nor is it likely to have changed over a mere 400 years. With any luck, archaeologists 20 million years in the future will dig up some cathedrals and finally put the matter…..at rest**.
Hey, if you can’t get enough complex fluids, check out one of the longest running experiments ever: The pitch drop. Pitch is a resin formerly used to seal boats and drop on invading armies. When cooled, it is hard and can be shattered with a hammer, but it actually flows over a measurable time period. Thomas Parnell, an physics professor at the University of Queensland started the experiment in 1927, and since then the pitch had dripped 8 times. D. Eric Franks on the comments mentioned that the 9th drop is due to fall anytime now. So if you have nothing better to do, you can watch the live feed and perhaps even make history: For in the 86 years it has been going, nobody has actually caught a drop in action.
Special thanks to Redditor N8CCRG, who provided the best explanation I had seen regarding glasses, non-newtonian fluids, and long range order. I wanted to feature them as the third puppet in the comic, but did not receive a response in time.
*In the defense of the other articles, they actually reported the science right, but the sensationalized headlines didn’t do the research justice.
**Oh c’mon, I had to sneak another one in there.
Boom goes the Strip Search! Thanks, Obama.