On Thu, May 14, 2020, 11:20 PM Stephen J. Turnbull 
 > I can teach a child why a glass will break permanently when you hit
 > it while a lake won’t by using the words “solid” and “liquid”.

Terrible example, since a glass is just a geologically slow liquid. ;-)

It isn't though. I used to believe the old urban legend about glass being a (very slow) liquid too. It makes for good "impress your friends" chatter at a certain point. But it's not true, glass is an amorphous solid, and old windows are thicker at the bottom because they hung them that way.