And this is a popular misconception that just drives Mikey crazy. So, let's dispel this crazy notion and rerun a paper Mikey authored in this very topic two decades ago, once again:
So, what is it this mysterious substance we call glass? Is it a solid? Is it a liquid? Do four out of five dentists recommend it? (Which makes you wonder who visits that one out of five dentist, and what does he recommend?...Ed) Let's join hands and explore the subject together.
Okay, so let's assume it's a liquid for a minute. It has to be, right? We've all heard the stories about pulling glass out of old windows and how the pieces were all thicker at the bottom proving that the glass was slowly flowing downward. Heck, the way the glass was flowing pretty soon all our churches will have their sanctuaries full of puddles of flowing stained glass windows. You'll have to step over the Good Shepherd and his sheep to get to your pew! With all those uncovered windows with all their cancer causing light streaming through them congregations will be forced to take communion wearing Vuarnet sunglasses and wearing sunscreen. Actually it's a sham. Old glass is typically mouth blown and therefore varies sometimes quite significantly in thickness, disproving the notion that glass might be a liquid.
Well if it's not a liquid then it stands to reason that it's a solid, right? Webster's Dictionary defines a solid as "a substance of definite shape and volume; not liquid or gas." There you go, problem solved. But, hey, wait a minute. Isn't something a solid only when its molecules are motionless and lined up in flawless geometric fashion, like your grandma's furniture doilies. We call this "crystalline" (the solid, not grandma's doilies, unless she seldom washed them). A liquid on the other hand is quite the opposite. Its molecules are constantly in motion and entirely random in structure. Well, what do we do now? It seems then that according to the scientist, glass is neither a solid or liquid because its molecules are motionless (like a solid) but random in configuration (like a liquid)- so we'll call it a liquid?
Actually a better word is vitreous.
If you look around, there's lots of stuff that's sometimes a liquid and sometimes a solid. Take that stuff wrapped in foil at the back of your fridge for example. Or water. Or iron. At any given moment, their state depends on their temperature. Water's molecular structure is random until the temperature moves down to zero Celsius (how come they don't use centigrade?) when its molecules start to crystallize- namely, line up in perfect lattice-like order and stop moving. Below zero and bingo, now it's a solid. And the amazing thing is that zero degrees is like a light switch. Above it's a liquid, below, it's a solid. But vitreous substances (like glass in case you've been sleeping until this very moment) do not have a freezing or melting point. As temperature decreases the free flowing molecules in molten glass simply slow down to the point where they just won't move anymore. But they stay random with no crystallization occurring. Got it?
So, glass then is neither a liquid nor a solid, but it's sleazy and exhibits definite characteristics of both. You might say we now have Four States of Matter instead of three- liquid, solid, gas and glass.
But don't take our word for it. Go to Corning Glass' website and read for yourself-