It used to be widely claimed that (apparently solid) glass was known to be liquid, because old window panes are thicker at the bottom. As a boy, after I got my first toy of Silly Putty (in 1955. It was called "Nutty Putty"), which will slowly flow like a liquid but which can also break irregularly if struck with a hammer (like glass)* -- and learned it was a silicon compound, I was entirely convinced. But more recently I've read that this has been found to be a myth. Rather, it is said, glass windows, etc., are in fact solids. And, the old windows were sometimes thicker at the bottom only because they were made of blown glass, with much less precision. --Dan _________________________________________________________________________________ * It also bounced and could pick up the reverse image of something printed in a newspaper -- but you all probably knew that. I can't find any reference to the trade name "Nutty Putty", for some reason. Especially since it's a more memorable name than "Silly Putty", I'd expect that someone must have obtained the rights to that name. On 2012-12-26, at 1:54 PM, meekerdb wrote:
On 12/26/2012 1:36 PM, Warren Smith wrote:
http://www.lassp.cornell.edu/sethna/OrderParameters/BrokenSymmetry.html
Interesting view: phase changes are about symmetry changes.
One counterexample to this is glasses (amorphous solids). They can be solid or liquid but no symmetry changes that I know of.
I don't think they are solid, they're just liquids with very high viscosity.