RE: OK,is Glass a ..................

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sundownhawk -> RE: OK,is Glass a .................. (10/2/2007 7:20:19 PM)
quote: Glass by definition is an amorphous solid material. it is amorphous because it is neither a solid or a liquid, but exists in a vitreous state ORIGINAL: InkedMaster What he said. P.S. was it half full, half empty or too small?

ChicagoSwitchMal -> RE: OK,is Glass a .................. (10/2/2007 7:26:16 PM)
It's an Amorphous solid as the position of it's atoms are not fixed. Common sense says glass should be considered a solid since it is rigid according to everyday experience. As I can not use it at a liquid it is pointless to consider it such.

samboct -> RE: OK,is Glass a .................. (10/2/2007 8:30:29 PM)
Gack no atoms are ever fixed- even at absolute zero- they'd have vibrations. Glass is just a highly viscous liquid- that we have a time frame that doesn't see it's flow is our problem- not the glasses. Solids have short and long range order- glasses have short range order but not long range order. Most liquids have very little short range and no long range order- except if we start talking about liquid crystals. Things like maple syrup- i.e. viscous liquids do have some short range order though. We may just have a timing issue here too- the short range order of liquids like water is too short to measure (I'm guessing here- it's silly speculation and probably wrong.) Probably the best definition is if it undergoes a glass transition- a discontinuity in phase between free flowing liquid and higher viscosity (IIRC- I took this exam over 20 years ago.) it's a glass. My recollection of this transition means that the wikipedia definition is either a bit off or misleading- I do remember that a glass transition is a discontinuity- weird things happen. Physically, it's the transition from free roaming molecules (liquid) to the establishment of some short range order. But glasses are definitely NOT solids. Sam

dcnovice -> RE: OK,is Glass a .................. (10/2/2007 8:38:54 PM)
quote: Glass is just a highly viscous liquid- that we have a time frame that doesn't see it's flow is our problem How long a time frame would we need?

HaveRopeWillBind -> RE: OK,is Glass a .................. (10/2/2007 8:40:18 PM)
It's a really stiff liquid, but given enough time it does flow at room temp. Don't believe it? Leave an empty beer bottle on the counter for a few thousand years, when you come back to check on it it will be a puddle on the floor. Really!

dcnovice -> RE: OK,is Glass a .................. (10/2/2007 8:44:16 PM)
quote: a few thousand years I was figuring it must take a while. There's glass that's been in cathedral windows for centuries, and it still seems intact. I wonder if they've found any glass items in the pyramids.

HaveRopeWillBind -> RE: OK,is Glass a .................. (10/2/2007 8:56:30 PM)
DC I'm no Egyptologist, but I have never heard of any being found. Then again I'm not sure if glass was even made that long ago. Might be some on here better informed in that area.

dcnovice -> RE: OK,is Glass a .................. (10/2/2007 8:57:54 PM)
I can't think of any being found either, though I think the blue stripes on King Tut's death maks are blue glass (which was supposedly more valuable to the Egyptians than gold).

Ponyboy7 -> RE: OK,is Glass a .................. (10/2/2007 9:34:14 PM)
It is a "vitreous" solid. This means it is a solid, but it is not a crystalline solid. For example, volcanic glass, will become crystalline over time (see wikipedia), but it was always a solid; it is not undergoing a phase transition. Just because a solid does not have a ordered crystal structure, and is thus vitreous, does not mean it is any less of a solid. Other examples are plastics and gels. Anyway, if you don't believe me, then check out Journal of Non-Crystalline Solids. Glass is the subject of many articles in this solid state physics peer reviewed journal. The journal self describes as: "A journal on the chemical, electronic, optical and mechanical properties of glasses, amorphous semiconductors and metals..." It also notes that papers on the liquid state of these solids are also included in so far as the properties of the liquid are relevant for the formation of the solid. I was a physics major as an undergrad and have taken a couple courses in solid state physics; glass was one of the materials discussed because it is a common non-crystalline solid and can have interesting properties. Anyway, it is not uncommon to think of non-crystalline solids as viscous liquids, but one must understand that having a defined crystal structure is not a requirement to being classified as a solid. Glasses have melting points (1723 °C for silica glass) just like any other solid, and have well defined phase transitions at 1 atm as well as a defintite heat of fusion.

samboct -> RE: OK,is Glass a .................. (10/3/2007 6:07:39 AM)
Hmm- well, I was (well, sorta still am) a chemistry Ph.D.- and to a chemist- solids have long range order. I will also point out that some solids don't have melting points- they decompose before they melt. An example would be any thermoset resin, such as an epoxy. And what I remember about glasses is that they DON'T have a well defined phase transition- it's discontinuous- meaning it leads to hysteresis (actually, I think this is some glasses do, and some glasses don't, but like I said, it's been awhile.) Here's a made up example of what I'm talking about- Glass A has a glass transition temperature of 550C. Let's start at 700C- where it's a liquid. So we cool it down to 550C, lo and behold, the material begins to gel and then doesn't move. Looks like a piece of glass. Now let's go the other way- let's take the glass and heat it up to 550C. Why is nothing happening- it still looks like a piece of glass? Because the temperature isn't sufficient to rupture the bonds of the long range order. In order to do this- we have to go up to 575C before anything happens. This isn't a matter of time- you can fully heat glass A to 550C and nothing will happen for years. Hence there's a hysteresis- things happen differently depending on how they're approached- and this is NOT a well defined phase transition. A well defined phase transition is from water to ice- happens at 0C and it doesn't matter whether you start with liquid water or ice, you'll get to the same spot no matter how you approach things. A good definition of a glass is really not easy- the one I remember using was that it was any material that has a glass transition temperature i.e. that hysteresis I just described for glass A. A crystalline solid is one that does have a sharply defined melting temperature- it's the temperature where the long range order goes away. DCNovice- I'm assuming your question has been answered- and yeah, the scale is thousands of years to hundreds of thousands of years IIRC. Put it in more gravity and more heat, and it'll flow faster. Sam

LadyEllen -> RE: OK,is Glass a .................. (10/3/2007 6:13:49 AM)
it be witchcraft I tell thee! the devil hisself's own creation! a curse be upon ye that look through his liquidy-glassy-solidy invention! a curse! E (failed Chemistry)

LaTigresse -> RE: OK,is Glass a .................. (10/3/2007 7:05:40 AM)
I am going with solid by comparison. Given that glass is made of mineral aka rock and rock can be turned into liquid via heat, example volcanic crapola and metal which is pretty solid most of the time yet given enough heat will go liquid...... So yeah, until I can stop washing wine glasses and have them break with my hand in them and cutting myself.......it's solid.

samboct -> RE: OK,is Glass a .................. (10/3/2007 9:04:48 AM)
Visitor from the past walks up to the receptionist at Du Pont and announces- "I sirrah, am an alchemyste. Hast thou need of art such as myne?"

RCdc -> RE: OK,is Glass a .................. (10/3/2007 9:19:14 AM)
quote: ORIGINAL: camille65 Liquid. Very old glass windows are thicker on the bottom edge. This is an Urban Legend. Glass is an amorphous solid. Peace the.dark.

AquaticSub -> RE: OK,is Glass a .................. (10/3/2007 12:03:01 PM)
quote: ORIGINAL: Aileen68 It's a container meant to be frosted with really cold beer in it. I like this answer.

FullCircle -> RE: OK,is Glass a .................. (10/3/2007 1:06:09 PM)
Glass is a solid at room temperature just as steel is a solid at room temperature. Maybe this is all above my head but I was always told three states of material exist; solid, liquid and gas. A material can exist in any of these three states depending on the boiling point and evaporation point of the material. I could get a dog turd to turn into a gas if I cooked it at the right temperature. So what are you on about when you talk of a super cooled liquid? If it was a super cooled liquid would it not melt at room temperature? You confuse me you people. Remember molecules start off bunched together, then as you give them energy through heat they start to vibrate and move around slightly then ultimately they move away from each out. A viscous liquid is just one that has the molecules closer together than a non viscous one. With enough energy I could make hydrogen a solid there is nothing special about it just because at room temperature it’s a gas.

CuriousLord -> RE: OK,is Glass a .................. (10/3/2007 1:34:44 PM)
[Edit: Deleted. This post was just me being sarcastic out of frustration. Have fun.]

mnottertail -> RE: OK,is Glass a .................. (10/3/2007 1:40:10 PM)
Glass is a figment of your imagination....it doesn't really exist unless it is wrapped around an ice cold beer. Edgar Cayce

FullCircle -> RE: OK,is Glass a .................. (10/3/2007 2:02:45 PM)
Glass is Chinese for grass IMHO.

philosophy -> RE: OK,is Glass a .................. (10/3/2007 3:23:17 PM)
quote: ORIGINAL: Darcyandthedark quote: ORIGINAL: camille65 Liquid. Very old glass windows are thicker on the bottom edge. This is an Urban Legend. Glass is an amorphous solid. Peace the.dark. ..odd, because i have seen the 'thicker at the bottom effect' in really old glass with my own eyes.........

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