The house in France Ilive in was built in the 16th century, and though I doubt any of the windowpanes are original, some of them are quite old. People go all wavy as they pass my office. This tickles me: Those vertical distortions in the panes remind me that glass--brittle, breakable glass--is really a fluid. The windows of medieval cathedrals are thicker at the bottom, I've heard, because the glass has pooled there; and even the little streams in my own panes seem to evoke the transience of existence: Time is a river; glass is a river--you get the idea.
"The idea that glass is a fluid is a very widespread myth," says Yvonne Stokes, a mathematician and spoilsport at the University of Adelaide in Australia. "I was told it as a fact by my adviser. And once, a class of schoolchildren came into the lab, and one of them told me the very same thing. If you want to talk microscopically, then you can call glass a fluid. But people understandably tend to think that if it's a fluid, it flows. It's that notion that's false." Stokes has recently proved with detailed calculations that old windows could not have flowed perceptibly.
