Glass is Liquid?

[atinymonkey]

No, it's solid. See above ^^

 

Also, see my wrongness in the first reply and subsiquent bitterness.

[YT2095]

Hyper viscosity sounds nice too

 

 

still a Liquid though

[swansont]

YT2095 said in post #27 :

Hyper viscosity sounds nice too

 

 

still a Liquid though

 

I've linked to a number of credible (IMO) sources who disagree. Do you have anything to support your contention that it's a liquid?

[YT2095]

no probs, here ya go

http://www.sciencenet.org.uk/database/chem/materials/c00138b.html

 

ps; I used to work for them too

[Alarium]

Liquid! Liquid! Liquid! *runs off before he can be contradicted*

[VendingMenace]

i was always under the impression that "supercooled liquid" referred to a liquid that had been cooled beyond its melting point, but still remained liquid. These states were referred to as "frigile" becuase for most of them, the introduction of any perturbance caused them to crash out of this state into the solid.

 

Am i mistaken in this?

[Dudde]

I still haven't read that link

 

I'll just assume it agrees with me

[swansont]

YT2095 said in post #29 :

no probs, here ya go

http://www.sciencenet.org.uk/database/chem/materials/c00138b.html

 

ps; I used to work for them too

 

The first sentence from your link:

"In any meaningful sense of the word, glass is not a liquid: it is as solid as any other solid."

 

I don't see how this bolsters your case.

[Dudde]

read the rest

[Sayonara]

YT's link:

 

General, unfunded scientific opinion from these people:

http://www.sciencenet.org.uk/intro/scienceline/staff.html

 

 

Swansont's link:

The combined expertise of 9 experts in glass and transition materials.

 

 

Hmmm... might have to flip a coin for this one

[Dudde]

quiet you, they're lying

[Sayonara]

Dudde said in post #34 :

read the rest

Yeah, considering the temperatures at which glass is usually worked I'm thinking that normal room temperature is waaaaay below this "glass temperature", so far below in fact that the material is most certainly considered a solid.

 

The arguments against this are an abuse of both logic and English.

[YT2095]

You mentioned "unfunded" that is indeed true, but certainly not a flaw, in fact it`s alot more likely to make any info given unbiased.

SFN`s unfunded, but we have some pretty great minds here and the info given is often of quality.

but anyway, for the sake of peace, I will say that glass is closer to being a solid at room temp than it is a liquid. OK

[Sayonara]

YT2095 said in post #38 :

You mentioned "unfunded" that is indeed true, but certainly not a flaw, in fact it`s alot more likely to make any info given unbiased. SFN`s unfunded, but we have some pretty great minds here and the info given is often of quality.

SFN is privately funded by Blike. ScienceNet did have funding, but it was taken away. What does that tell you?

 

but anyway, for the sake of peace, I will say that glass is closer to being a solid at room temp than it is a liquid. OK

You mean like I did in my first post in this thread, when you told me I was wrong?

[swansont]

Dudde said in post #34 :

read the rest

 

I did read the rest; it's wrong. There are no refernces included to make me think otherwise.

 

Basically it says that glass doesn't behave like a crystalline material. Big surprise -it's not a crystalline material! There are a number of material that behave like glass (amorphous materials), so much so that they coined the term "glass transition."

[Duke]

If you got a bar of chocolate and heated it; it would start off as solid and then slowly become softer, then it would be runny and you would have a liquid. It wont just instantly become a liquid.

[VendingMenace]

of course a chocolate bar is not a pure substance either, which is what we usually consider when talking about sharp phase transitions.

 

THough, it is rather humerous that you choose chocolate as your example. You see, the waxy substance that is produced by the coco bean (it is called coco butter) is quite interesting. It is one of the few homogeneous lipids produced by plants. That is, the plant produces coco butter and pretty much only coco butter in its bean. Thus, when harvested, coco-butter is naturally a homogenous wax, a pure substance, if you will. This means that coco butter does have a sharp mealting curve.

 

It also turns out that coco butter is one of the main ingreadents in chocolate bars, so much so, that a chocolate bar pretty much has a sharp meliting point too. That is, it has a temperature at wich below it is solid and above it is liquid.

 

It wont just instantly become a liquid.

 

I think you are missing the point. WE are not saying that melting is an instantaneos process. WE are saying that it happens at a finite point. That if you walked into a room that was at -1 celcius, you would expect to find water in its solid form, and that if you walked into a room that was at 1 celcius, you would expect to find water in its liquid form. That is all.

 

If you got a bar of chocolate and heated it; it would start off as solid and then slowly become softer, then it would be runny and you would have a liquid.

 

RIght, again, things do not happen instantaneously. Why? WEll for one, the chocalate bar is not uniform in temperature, when you start heating it, the inside will remain cooler than the outside. Also, melting absorbs heat. So, the chocolate bar while melting must continously be absorbing heat. However, long it takes to absorb this heat and bring the chocolate above its melting temp, that is how long it will take to melt.

 

WE see the same thing with ice. You can put a ice cube on a warm stove (80 celcius) and it will not just instantly melt, despite the fact that it is well above the melting temp for water. This is becuase it will take a while to heat up the ice to above its melitng temp.

 

 

Now so far, this discussion has delt with large objects (ie, ice cubes, chocolate bars). Of course, on a moleculare level, it is pretty darn close to instantaneous. That is to say, as far as the first layer of molecules are concerned, when they reach a temp above the melting temp, most of them will just suddenly become liquid. Just like that. The reason is, right at that temp the molecules (on average) have just gained enough energy to overcome the latice forces (or in the caes of lipds, the van der waals and other forces) that hold them into their solid phase. This is the reason why we have sharp melting temp.

 

Yeah, so in conclusion, you are right, things usually do not just instantly melt (at least when we consider a large body of somthing) but this does not mean that the substance does not have a sharp melting point.

[Dudde]

wait....what point am I supposed to be arguing here? You didn't read the link, or that glass is really liquid? is ice liquid?

[VendingMenace]

lol

 

I was just responding to duke's post. He seemed to be saying that stuff does not have a sharp melting point and he was using chocolate as an example, thats all.

 

As far as glass goes, i am in the amourphose solid camp, but i said that a long time ago back in the beggining of this thread.

[Pinch Paxton]

Interesting topic. Mix custard powder with water, and press your thumb into it, that's interesting too!

[Guest GrandPhoenix]

VendingMenace said in post #20 :

It is just a solid and then in the next instant, it is a liquid.

 

Oh, really? Are you sure? Usually, doesn't part of the substance shift phase before another part?

 

For example, haven't you ever seen a pot of water steaming before it's temperature reaches 100 degrees celsius?

[VendingMenace]

hmmm....i see the source of confusion now.

 

Alright, the transition across pahses is instantaneous for the particles that are undergoing the transition. THerefore, in a idealized situation, where heat transfer within a substance was instantaneous (ie, every point in the substance is at the same temp) then a substance would instantaneously change from one phase to another.

 

Unfortuantely (or fortunately, perhaps) this is not the case. THere are temp gradiants in bulk substances. Becuase of this, we find that it takes time for the entire substance to undergo the phase change. That is why we observe that it takes time for an entire chocolate bar to melt or an entire pot of water. That is also why we observe that part of a substance sometimes changes phase before other parts.

 

However, this does not change the fact that for the molecules that are undergoing the change, this change is instantaneous. At one point they have too little energy to excape from they solid matrix, and at the next they have enough and escape from the solid matrix. (I guess that you could try to argue that this escape takes time, as well, and it might, but the timescale is too short to notice when you are just watching something melt with you eyes and probably more intramentation)

 

I think this is right, i will have to think about this a bit more. But i am pretty sure.

[YT2095]

if it helps, use candle wax as opposed to choc. as choc is just a form of hydrocarbons just the same, only with coco solids and sugars in suspension.

but hey, what do I know.. I quit this thread ages ago for the sake of Peace ;-p

 

 

 

I just ddin`t want it all brown and messy

 

 

[VendingMenace]

well, after thinking about this for a day, i have come to the conclusion that i was incorrect in my above statement. I still hold that it is true that for an individual molecule undergoing a phase transition, the change is instantaneous (or nearly instantaneous). HOwever, for a bulk matierial, where the change is clearly not instantaneous, the time needed for the transition is not just due to the lack of an ideal material.

 

Even if we had an ideal material (ie, one where heat transfer occured instantaneously and without loss of energy) i am unsure as to whether we would ever observe a instantaneous phase change for the intire material. This is owinig to the fact that phase transitions are either endo or exothoermic. Thus, (in melting for example) when the molecules start to come off the material, the steal energy from the system in wich they are in, lowering the temp of the substance, so that the rest of the substance is no longer at the melting temperature. Thus, we are required to continualy supply energy to the substance. So, unless we had a reserve of energy that also was instantly transferred onto the substance, we would never observe an instantaneous transfer between phases.

 

Anyway that is kinda what i am thinking now. But of course i could be wrong again.

[Duke]

How long is it going to take my window to melt then.