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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.
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