Incorrect it is a solid. edited to add: obviously I mean at STP! If we are talking about STP and the gravity in the earths range, then this to is incorrect. You got one right You have bought into an urban ledgend and it doesn't scare me in the slightest. An amorphous solid like silica glass only means that it does not have defined melting point like a crystaline material. Glass technologist typically talk of the softening point of glass also called the glass transition temperature. The melting point of glass is arbitrarily set at a viscosity range, there is no clear change from solid to liquid as there is with a crystaline material. Look at this or search for glass vs viscosity. Notice that the viscosity axis is typically the LOG of viscosity. Glass will not flow over time, asssuming that standard earth type conditions. End of story. Edit to add: Welcome to the forum.Please Register or Log in to view the hidden image!
Hello origin, I'm going to correct you using sources. https://en.wikipedia.org/wiki/Amorphous_solid "In condensed matter physics and materials science, an amorphous (from the Greek a, without, morphé, shape, form) or non-crystalline solid is a solid that lacks the long-range order characteristic of a crystal. In some older books, the term has been used synonymously with glass. Nowadays, "amorphous solid" is considered to be the overarching concept, and glass the more special case: A glass is an amorphous solid that exhibits a glass transition.[1] Polymers are often amorphous. Other types of amorphous solids include gels, thin films, and nanostructured materials such as glass." https://en.wikipedia.org/wiki/Glass "Glass is a non-crystalline amorphous solid that is often transparent and has widespread practical, technological, and decorative usage in, for example, window panes, tableware, and optoelectronics." I implore all skeptics to research this subject, and prove me otherwise with modern reliable sources. Thank you. Edit: Not a very comforting welcome, to say the least.
I see that I did not provide an answer in regards to the "melting glass myth". http://www.scientificamerican.com/article/fact-fiction-glass-liquid/ "Whatever flow glass manages, however, does not explain why some antique windows are thicker at the bottom. Other, even older glasses do not share the same melted look. In fact, ancient Egyptian vessels have none of this sagging, says Robert Brill, an antique glass researcher at the Corning Museum of Glass in Corning, N.Y. Furthermore, cathedral glass should not flow because it is hundreds of degrees below its glass-transition temperature, Ediger adds. A mathematical model shows it would take longer than the universe has existed for room temperature cathedral glass to rearrange itself to appear melted." Yes - glass would, over the course of many billions of years - appear to melt.
Why would you say that when you just posted the following? A mathematical model shows it would take longer than the universe has existed for room temperature cathedral glass to rearrange itself to appear melted." Glass would appear to melt no more than a piece of steel. I would also say that glass would flow much less than steel since creep is a well known feature of steel and is not feature if silica glasses. So implying that glass is somehow 'less' of a solid than a crystiline solid is silly and pointless. I work for a glass and ceramics company, but I am only a chemical engineer, however my wife is a ceramic engineer and more specifically a glass technologist. I really trust her and her sources. Sorry you feel that way. I disagree with you assessment, I wasn't trying to attack you.
They do not say how much longer than 14 bly it would take for a silica based glass to 'appear melted'... If this same mathematical model was applied to iron it would more than likely indicate that it would take a substantially shorter time to 'appear melted' since the bond strength of Si-O is about 4x higher than the Fe-Fe bond strength. Silica based glass at room temperature is a solid. The solid glass does not have a long range crystal structure but is none the less a solid, your terror not withstanding.Please Register or Log in to view the hidden image!
Remember that what you speak here and elsewhere on this forum - may very well become an artifact of the future internet archive. To all individuals whom question this argument regarding glass and its properties, please study. Do not trust anything you read from any individual on an online forum. To everybody involved - please study.
I think the attached Scentific American article gives the right idea, http://www.scientificamerican.com/article/fact-fiction-glass-liquid/ even though it does contain the nonsensical statement that a glass is "neither a liquid....... nor a solid" but an "amorphous solid". (Er, so that means an amorphous solid is not a solid, eh? How does that work? Please Register or Log in to view the hidden image!) There is a more scientifically rigorous explanation here: http://math.ucr.edu/home/baez/physics/General/Glass/glass.html The key points would appear to be that: - unlike a crystalline solid, a glass does not release latent heat of fusion when it forms by cooling from the liquid state, - it is thus metastable, with respect to its thermodynamically more favourable crystalline phase, - its stability is a kinetic effect, due to the way that the viscosity of glass increases on cooling, which prevents crystalline order from developing. - some glasses can devitrify to some extent over time, moving to the more thermodynamically stable state. In general, solids can exist in a number of phases, representing different types of atomic or molecular order, with varying degrees of thermodynamic stability, which are often affected by temperature and pressure. Different phases of pure elements are called "allotropes", e.g. diamond and graphite are different allotropes of carbon. A glass is an amorphous solid, which has a particularly low degree of order in its structure. But to call it a "liquid" strikes me as a bit perverse, as it has almost none of the properties that characterise a liquid. P.S. One potential source of confusion can be in what "phase" means. It can be used in the sense of a state of matter (solid, liquid, gas) or to denote different forms within each of these states of matter. More here : https://en.wikipedia.org/wiki/Phase_(matter)
I would say it is absurd to call glass a liquid, it has no characteristics of a liquid except that neither are crystalline. I think most people understand that ice is a solid but ice actually does flow in the form of a glacier. LOL, agreed.
Well more or less, yes. But, from a chemist's viewpoint, it is somewhat intermediate between a classical solid and a liquid in at least a couple of respects: - it has the same lack of order as a liquid, - it still contains within it the latent heat of fusion, which is given up only when crystals form. However its mechanical properties are indisputably those of a solid and, as we have seen, it is classified as an "amorphous solid". And I do take your point that solids do flow, over long timescales, esp. when subjected to pressure. Glaciers are one example. "creep" in metals is another (I think you pointed this out earlier). Plate tectonics provides a third example.
I like that. I had not thought of it that way. Devitrify glass is very common and is used to control the properties of the glass ceramic. My wife is currently working with a particular glass ceramic application and when I mentioned your statement to her this morning she showed me a graph of furnace temperature VS Differential Scanning Calorimetry (DSC) and you could see right where in the furnace cycle the devitrification occurred by the increase in the exotherm. Interesting stuff!
Ah, really? That would fit, certainly: how interesting. Actually I had not realised it was the high viscosity that inhibited crystal formation, creating this kinetically stable, but thermodynamically unstable, state. Good topic - even though it had nothing to do with DNA!
