Excerpt from Clearly Amazing
Clark Benson

4 Scientists consider glass an amorphous substance. This means it is not truly a solid or a liquid. It exists in a state somewhere in between. Though the molecules that make up glass have a messy arrangement, they still manage to bond together and become stiff. Glass reaches this state once it has cooled after introduction to intense heat. In fact, the opposite is also true. Introducing a piece of glass to extreme heat can return it to a liquid form.
Although glass is thought of as "stiff," it actually exists in a state that is between a solid and a liquid. Which could result in changing glass to a liquid state ?

A) having a volcano erupt near a highway
B) breaking glass into finely crushed pieces
C) lightning striking the roof of your house
D) heating a window pane to an extremely high temperature