Is glass a liquid

Answer 1

Answer

No. Or, more accurately, it doesn't really fit into either the "liquid" or "solid" categories.

The arguments that glass is a liquid come primarily from thermodynamics. Glass does not exhibit a sharp melting point; rather, it softens over a range of temperatures. Also, it doesn't show a nice sharp thermodynamic transition as it cools from the molten state.

Some people use this to call glass a supercooled liquid or, somewhat more accurately, a viscous liquid. The problem with this is that both terms are already used to describe things that have very different properties than glass and which are clearly liquid-like in their behavior, so while in an extremely narrow sense the terms might be technically applicable, they're misleading and confusing.

In any way that's meaningful to a layperson, glass is much more like a solid than like a liquid, and the modern consensus is that "amorphous solid" (or even simply "glass") is a more useful description.

The strongest "glass is a liquid" arguments that don't involve fairly esoteric points of thermodynamics have been refuted: glass does not exhibit flow in old windows (it's an artifact of the manufacturing process), and while glass does deform extremely slowly under pressure, it does so in a way that's more solid-like than liquid-like.

Answer

Yes and No. This depends on how the words "liquid: and "solid" used. It is possible to use a definition of liquid that fits glass. One definition of "liquid" used in science refers to its ability to flow over time. But another depends on the ability of a substance to wet things - a measure of surface tension. If this is applied, glass appears to be solid. It is called, for scientific purposes, an "amorphous solid."

The most usual definition of these two words is not dependant on scientific observations, but rather on personal observations. We do not see or feel glass flow, so it is normally considered solid.

Summing up, an answer to the question of whether glass is solid or liquid depends on the nature of words, rather than the nature of glass.

Answer

Glass is not a liquid. It is a solid at anything near "ordinary" temperatures. Glass is what is called an amorphous solid. That means glass doesn't arrange itself into a "regular" crystal lattice or crystal structure when it takes solid form. It has a somewhat robust range of plasticity, which is to say that it begins to deform and continues to do so across a "broad" temperature range before becoming liquid. There is a "problem" with glass that is due to less-than-perfect manufacturing techniques coupled with the way that older glass was installed.

The way glass was made back in the day left something to be desired. Glass was poured out, and it cooled as it "ran" over the surface onto which it was poured. This lead to variations in the thickness of the glass. Couple that to the habit of the "old school" installers who put glass in with the thick side (or edge) down, and you can see where some might think that glass "melted" or "deformed" over the many decades since it was put in. Not so, as some glass was installed "incorrectly" with the thick edge up.

We have seen the myth that glass was not a solid persist for a long time. But investigation by the thinking individual will reveal that glass is a solid. Use the link below to learn more as it will lead you to the Wikipedia post on glass. The scientific truth is told there, even as it was here.

Answer 2

Sort of - a very viscous one. But it acts as a solid.