Glass’s weird behavior under a microscope has made it the subject of longstanding confusion
Photo by Flickr user Fabi42
As a young know-it-all, one “factoid” I always loved dropping on my friends and colleagues was the one about glass not being a real solid. Old church windows, the story went, had become thicker on the bottom over time, as the glass, though appearing solid, continued to very, very slowly flow with gravity. I first heard this idea in an art history class, when my teacher, an elderly German woman with a white shock of hair, led me astray, her authoritative, Einsteinian aura beyond question at the time. But she was wrong, and I dutifully repeated the myth over and over to my credulous chums. Sorry, guys. It turns out the variation in the thickness of old windows was due to a quirk of how large panes were made in medieval times, and glass is, in fact, a true solid, although it takes a little time to get all the way there.