Why is glass a liquid?

Answer 1

There is no clear answer to the question "Is glass solid or liquid?". In terms of molecular dynamics and thermodynamics it is possible to justify various different views that it is a highly viscous liquid, an amorphous solid, or simply that glass is another state of matter that is neither liquid nor solid. The difference is semantic. In terms of its material properties we can do little better. There is no clear definition of the distinction between solids and highly viscous liquids. All such phases or states of matter are idealisations of real material properties. Nevertheless, from a more common sense point of view, glass should be considered a solid since it is rigid according to everyday experience. The use of the term "supercooled liquid" to describe glass still persists, but is considered by many to be an unfortunate misnomer that should be avoided. In any case, claims that glass panes in old windows have deformed due to glass flow have never been substantiated. Examples of Roman glassware and calculations based on measurements of glass visco-properties indicate that these claims cannot be true. The observed features are more easily explained as a result of the imperfect methods used to make glass window panes before the float glass process was invented.

Answer 2

That is a common myth. It is perfectly solid. The reason why people think it is a liquid is because when glass smithing was new, we weren't so good at it. Panes would often be uneven, so to make the windows more stable, the wider part of the pane would be put at the bottom, hence the appearance of liquidity. There are some esoteric arguments from thermodynamics that allow people to stretch a point and claim that glass is a liquid, but most scientists today would call it an amorphous solid instead.

Answer 3

because it is it just flows very slowly very very slowly