eddie4fins
Pro Bowler
ckparrothead said:Yes, actually it is. Glass is classified as a liquid. And if you'll notice the stain glass windows of old cathedrals, the tops of the windows are extremely brittle, because through the years the glass has slowly poured downward and settled to the bottom of the pane, making the bottom part of the pane thick and the top part thin and brittle.
Is glass liquid or solid?
It is sometimes said that glass in very old churches is thicker at the bottom than at the top because glass is a liquid, and so over several centuries it has flowed towards the bottom. This is not true. In Medieval times panes of glass were often made by the Crown glass process. A lump of molten glass was rolled, blown, expanded, flattened and finally spun into a disc before being cut into panes. The sheets were thicker towards the edge of the disc and were usually installed with the heavier side at the bottom. Other techniques of forming glass panes have been used but it is only the relatively recent float glass processes which have produced good quality flat sheets of glass.