"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 which is neither liquid nor solid. The difference is semantic. Nevertheless, from a more common sense point of view, glass should be considered a solid since it is rigid according to every day 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." From the following website: http://math.ucr.edu/home/baez/physics/General/Glass/glass.html Please see the link for more information.

Solid. I have seen several mentions of glass being some sort of liquid, as in the previous question an answer and comment state that it is a super viscous fluid. But doesn't this defy common sense? It is brittle, it is not flexible to any great extent, if it is bent beyond even a few degrees it shatters, if force is removed it returns to its original shape, in all aspects it behaves as a solid, so it should be classified as a solid, and if the definition of a solid does not include glass, then the particular definitions used to determine a solid, gas or liquid are incomplete or inaccurate. Some claim that it actually flows and takes on the shape of a container in which it is placed, or sags and deforms over time, but these claims are entirely unsubstantiated, the warped windows they use as reference were warped when they were manufactured and have never changed shape, unless they are broken and shatter, that is. If they did, what of the oldest glassware ever found, much older than the windows in cathedrals that are used to "prove" glass flows, delicate vases and pottery with thin glass and glass making techniques that make for much softer glass and lower melting points, which by all means should flow much more than the window panes? These are completely undeformed, with absolutely no indication of flowing, sagging, deformation or taking on the shape of the container surrounding them. So why do some reputable scientists agree that glass is a liquid? It is because glass is unlike any other solid, while it is cooling and freezing, shifting from liquid to gas, there is no first order shift in the thermal properties of the glass, and no latticing or formation of crystalline structures on the microscopic level. The atoms do not arrange themselves in neat rows and patterns like other solids. If this is the definition which determines solid, liquid or gas phases, what of other things like water? As water approaches the freezing point there is a shift ABOVE the freezing point of 0C or 32F, where it stops shrinking and begins expanding, so at this point, where water is clearly a liquid which flows it should be defined as a solid because of the change in thermal properties, right? No, they ignore this because it defies the common sense definition of solid. What about when water freezes and becomes a solid? Does it have this crystalline structure and uniformity of pattern in the structures? No, but when it is further compressed and cooled, as under hundreds of feet of ice and snow, like at the bottom of a glacier or glacial ice, it changes in crytal structure from random disordered crystals to uniform parallel crystals, and actually changes in density and thermal properties, so it actually freezes and becomes a solid. Also, consider the surface of water, where there is no dense electric field above to scatter polarity and cause random charges the surface of the water becomes aligned, the atoms are all "pointing" the same way and create a bond, surface tension which holds the surface together in a crystalline or polarized structure, even in a dew drop or drop of rain the entire surface of the water is aligned so. So by this definition the surface of all liquids including water is actually a solid, because the atoms and molecules align themselves in a repetitious pattern similar to crystalline structures. But doesn't this then have multiple errors, defying the common definition of solid liquid and gas? Doesn't it completely annul any meaningful use of these terms and make them obsolete and inapplicable in the majority of physical sciences? So, if that is the case, either the definition and characteristics used to determine if a substance is solid liquid or gas must be changed, to actually comply with the common definition of the word, and the argument of glass being a liquid is purely academic musings based on a poor definition and semantics which are obsolete, a discussion which properly belongs in the language debates, not physical sciences. It is, for all intents and purposes, a solid as understood by any reasoning person. Just try putting crushed glass in a container and see if over twenty or thirty or forty years there is ever any change in volume as it flows to take on the shape of the container and fills in gaps.

While I agree with the other answers (which state that it's basically just a matter of semantics, because technically glass can be classified as a solid or a liquid), I think that using the "common sense" factor in an answer defeats the purpose. Common sense is what tells us that the Earth is flat, that the sun revolves around the Earth, that we should stop exercising when our breathing gets labored, or that since we FEEL okay, we can drive a car after having had several drinks. There are some things that common sense is good at guaging, but science is not one of them.

I belive that glass is a liquid. Very old stained glass from ancient is thicker at the bottom then at the top. For more info: www.zyra.org.uk/glassliq.htm

Glass is a liquid. If you look at a pain of glass that is very old you can see that it has slumped and is thicker on the bottom. Given enough time and the right conditions it would end up horizontal.

A solid

It depends what temperature it is at... At room temperature it's a solid though...

There is still much about the molecular physics and thermodynamics of glass that is not well understood. Here is a link to a thorough look at glass: http://tinyurl.com/39wjxb Here is what they state in conclusion............. 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 which 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.

Actually glass is a super cooled liquid.It is a highly viscous liquid.This fact can be observed when you look at the glass windows of really old buildings.The glass is thicker at the bottom which means it has flown slowly to the bottom.Which is a property of fluids(liquids and gases).

It is generally considered to be a liquid at any temperature in which it is useable. But that is on the molecular scale, for all intense and purposes it is a solid to you or me.

http://tafkac.org/science/glass.flow/glass_flow_the_thread.html OR, if you are feeling less generous: http://en.wikipedia.org/wiki/Internet_troll#Etymology

It is a Solid... Amorphous solid at that. my source is rather lengthy, so i'll just quote it directly from the general book of ignorance. - Glass is a solid, you may have heard it said that glass is a liquid which has cooled but not crystallised, and which just flows fantastically slowly. This is untrue - Glass is a bona fide solid. In support of the assertion that glass is a liquid, people often point to old church windows where the glass is thicker at the bottom of the pane. The reason for this is not that the glass has flowed over time, but that medieval glaziers sometimes couldn't cast perfectly uniform sheets of glass. when that happened they preferred to stand the glass into the window with the thick edge at the bottom, for obvious reasons. The confusion about whether glass is a liquid or a solid stmes from a misreading of the work of German physicist Gustav Tammann (1861-1938) who studied glass and described it's behaviour as it solidifies. He observed that the molecular structure of glass is irregular and disordered, unlike the neat arrangement of molecules in, say, metals. Reaching for an analogy, he compared it to 'a frozen super-cooled liquid'. But saying glass is like a liquid doesn't mean it is a liquid. These days, solids are categorised as either crystalline or amorphous. Glass is an amorphous solid. I hope this Helps, apologies if anyone has already covered all of this.

Well, From what I have read (from a couple of Dr Karl Kruszelnicki's books) Glass was thought to behave like a liquid, due to the fact (among a couple of reasons, most are forgotten to me) that some of the oldest windows in the world, Such as those in very old church windows, were thicker at the bottom than at the top. This suggested that the glass had flown from a relatively flat surface, into one that bulged at the bottom and was thick up the top. Its been a while since I have read the chapter on glass, but I can remember some church windows were found that were the reverse, ie Thick at the top and thin at the bottom (and hadn't been turned around) so the phenomenon was purely due to the lack of modern glass manufacturing equipment and skills, rather than incredibly slow flow. There was some more stuff on how the flowing couldn't be seen in modern testing, and this and that Blah complicated physics blah. As a side note, I just found: http://www.df.unipi.it/~leporini/DFWebSite/ReviewsTg/florin.html Which is a nice and short paper dedicated to this very question. Hope that helps!

the glass is solid because liquid is something like water like something you can drink something you can use something you can paint and solid is something that is hard to break or something you can't drink

Glass is a solid. The only reason that windows on old buildings look the way that they do is because the process is not as refined as it is now. It only appears to be a slow moving liquid, but it will shatter because it is a solid.

Glass is a general term for materials which have cooled too quickly for their atoms to reach a crystalline state. The most common form of glass is the clear material that keeps the breeze from coming thought he windows. Recently metal glasses have been discovered/developed which couild allow lighter stronger aircraft wings and gold clubs made oout of metal glasses. http://dsc.discovery.com/news/2008/06/23/glass-metal-atoms.html And as far as I can tell, glass is a solid, see article for details.