[krb]

Take a 60 year old piece of plate glass and measure it top and bottom and you will find that it has settled over the years with the bottom being thicker.

Nope. That's the urban legend. Check out that link.

In other words, while some antique windowpanes are thicker at the bottom, there are no statistical studies to show that all or most antique windowpanes are thicker at the bottom than at the top. The variations in thickness of antique windowpanes has nothing to do with whether glass is a solid or a liquid; its cause lies in the glass manufacturing process employed at the time, which made the production of glass panes of constant thickness quite difficult.

[dalereed]

I’ve done it several times to prove it to people.

[VanShuyten]

Glass is interesting. As an amorphous solid, it has no crystalline structure to lock the atoms in place. The base material, silicon dioxide (quartz) does have a crystal structure, but the stuff added to it to make glass prevents crystal formation. That makes it plastic at relatively low temperatures. It's essentially a solid at room temps and has no viscosity, but the temps that it starts flowing at vary wildly, depending on the dopants. Pretty cool stuff.

However, my BS meter is going off at the idea of a water- or alcohol "soluable glass".