Talk:Glass/Archive 3

History of glass
There is a historical inaccuracy in this article: "After the fall of the Empire, the Emperor Constantine moved to Byzantium where the use of glass continued, and spead to the Islamic world, the masters of glass-vessel making in the later Middle Ages." The Emperor constantine did moved to Byzantium long before the Western Empire collapsed-not to mention the fact that the Empire endured in the east. —Preceding unsigned comment added by 142.68.45.36 (talk) 22:19, 30 September 2007 (UTC)

Removed this innaccuracy Jdrewitt 13:36, 30 November 2007 (UTC)

Strength of Glass
In the introductory paragraph there is a statement about glass breaking into shards implying that it is weak in tension and strong in compression. This will lead the reader to understand that glass is a weak structural material in tension. My understanding is that glass can be a very strong material in tension and that is why it is used in fibre reinforced plastic, for instance. I suggest this statement be replaced with a more factual general statement about glass material strength properties. The property of breaking into sharp shards is probably more complex than a simple statement about tensional vs compressional strength can capture, without being misleading.

Mike —Preceding unsigned comment added by 207.189.247.235 (talk) 16:33, 10 October 2007 (UTC)


 * I removed this statement in the introduction as it is a little superflous and as you suggest not necessarily accurate. This information would also be more suitable in the properties section. Jdrewitt 18:10, 10 October 2007 (UTC)

Quick-failed good article nomination
Per the quick-fail criteria of the GA process, any article with cleanup or expansion banners and tags such as fact must be failed without a hold period. Please feel free to renominate the article when the necessary improvements have been made. Other major issues that would need to be dealt with include the following:


 * The prose is, for the most part, a pleasure to read. However, the article needs some work to comply fully with the Manual of Style. At present, the lead section is not a concise overview of the entire article. It only provides a basic definition of what glass is and how it's made. Expanding into a second paragraph which succinctly summarizes the rest of the article is necessary. Another issue is the use of blockquote formatting for quotations of less than four lines. This is improper per the MoS, and needs to be corrected. The sections Renaissance glassmaking, Industrial revolution glassmaking and Market structure also need serious expansion or merging in to larger sections.


 * Another area lacking is inline citations to references. Presently, every section in the article has large portions of text (i.e entire paragraphs and even subsections) that contain no inline citations whatsoever. The minimum for GA status would be a single ref at the end of the paragraph and for quotes. More, such as for potentially controversial statements, would be desirable. Remember that cites should always come after punctuation, not within it. This is especially true when citing quotations (such as in the bulleted list within Behaviour of antique glass).

Thank you for your work so far. If you feel this decision was in error, you are welcome to ask for a reassessment. Van Tucky  Talk 21:07, 27 October 2007 (UTC)

Contradiction?
Under "Glass in buildings" the article states: "Glass has been used in buildings since the 11th century". But under "Romans" it says: "Window glass was commonly used during the 1st century BC". If this isn't a contradiction, it needs clarification.Sreifa01 (talk) 07:10, 21 November 2007 (UTC)

Are either statements cited? If not they should both go, there is no point of having statement like this just for the sake of it. Jdrewitt (talk) 20:58, 21 November 2007 (UTC)

Both statements "Glass has been used in buildings since the 11th century" and "Window glass was commonly used during the 1st century BC" seem to be correct. I will look for a reference. It resolves the contradiction if the first statement is considered only for medieval Europe, and the second one is considered to be general.--Afluegel 14:11, 2 December 2007 (UTC)

See also section
A few points to be made here:


 * 1) The "examplefarm" tag may not be purpose-built for this section, but it serves the job. "See also" should not be a dumping ground for articles within the same topic; it should link to the most relevant links which for whatever reason can't be included in-article. The section should remain tagged until the problem is brought under control.
 * 2) "See also" is a pointer to articles. There's no hard in including anchors in the links if only a particular section of the linked article is pertinent, but they should be presented without piping to let the user know where they're being taken.
 * 3) Four columns, people. Many of these links should be covered by the article's category tags; category pages are the correct place for multi-column lists of relevant articles. We need not duplicate them here.

I believe most of these links can safely be removed, or incorporated into the article more directly. Chris Cunningham (talk) 12:09, 13 December 2007 (UTC)


 * The Wikipedia Manual of Style itself contains 15 links in its see also section, the links in the manual of style are also annotated which kind of makes the above comments slightly baseless. The links in this article are relevant to glass and therefore the tag is invalid and has been removed. A cleanup tag would be more appropriate (but still uneccessary) but the "examplefarm" tag is certainly NOT appropriate for the job  Jdrewitt (talk) 13:48, 13 December 2007 (UTC)


 * I've re-tagged using a proper cleanup tag. WP:MOS has fifteen links; this article has thirty links and is half the length. Furthermore, WP:MOS serves as help documentation and can thus perhaps be forgiven for being comprehensive. I would ask again why you feel that these links should be included here when they are already collected within Category:Glass, which is linked in the article's footer. Chris Cunningham (talk) 14:16, 13 December 2007 (UTC)


 * Why not just delete the entire section then? It is obviously superflous when looking at Category:Glass Jdrewitt (talk) 15:16, 13 December 2007 (UTC)


 * That's an option, but it's quite a bit more drastic. If every current link is indeed already in Category:Glass then I reckon that's a good call. However, there may be articles related to the subject but not subsumed within it, and those are really the meat of seealso sections in my mind. Chris Cunningham (talk) 15:42, 13 December 2007 (UTC)


 * I deleted all links that are already contained in the Category:Glass page. For consistency, I suggest the remaining links should also be placed in the category page instead of being linked from the article Jdrewitt (talk) 16:15, 13 December 2007 (UTC)

Merge tag
Calumite and marvering are both one-sentence stubs. They could both easily be rolled into the manufacturing section. Chris Cunningham (talk) 14:25, 13 December 2007 (UTC)
 * Sounds reasonable to me. Teapotgeorge (talk) 15:02, 13 December 2007 (UTC)


 * I performed the merge, and redirected those pages appropriately. I didn't notice this has been a recent discussion, so I apologize if it was too soon. If any issues come up we can always revert everything and discuss. -FrankTobia (talk) 00:48, 14 December 2007 (UTC)

Refractive Index
At what wavelength are the values for refractive index taken in the glass properties tables? This should be specified as n is dependant upon λ Jdrewitt (talk) 11:38, 14 December 2007 (UTC)


 * The subscript D indicates the wavelength of 589.29 nm, see Fraunhofer lines --Afluegel (talk) 12:26, 14 December 2007 (UTC)


 * I think it would be wise to specify this in the article, all variables should be defined, even if they are in common use Jdrewitt (talk) 13:04, 14 December 2007 (UTC)


 * All right, I added a footnote. --Afluegel (talk) 17:03, 14 December 2007 (UTC)

Liquidus temperature
The Liquidus temperature is a very important property because, if not considered, it leads to crystallization and failure during production. Therefore, TL should not be deleted in the properties table. If possible, for most compositions TL should be stated.--Afluegel (talk) 12:30, 14 December 2007 (UTC)


 * That's fine, I deleted it because it wasn't known for many of the compositions but yes, was probably a mistake. I think we need to include the transmission properties and other optical properties which can lead into the discussion of the optical applications of some glass compositions.  The other properties will be helpful to discuss why glasses are suitable for their own specific applications. Jdrewitt (talk) 13:02, 14 December 2007 (UTC)


 * Yes, the liquidus temperatures are important. I will try to find more TL data for the table. In case there is a reason to delete a column in the table I would start with the surface tension because the values are not very certain, despite they were measured and they are well referenced. Concerning transmission spectra there is one in the article soda lime glass, but unfortunately, without reference. -- Afluegel (talk) 17:18, 14 December 2007 (UTC)

Glass production
I think for the article to be good there need to be at least some technological details about industrial glass production, e.g., common commercial batch materials, batch preparation, melting in glass furnace, some forming techniques (incl. floating, blowing, pressing, casting), annealing, and surface treatments (tempering, ion exchange, IR coating) etc... The article Glass container production has some of the details needed, I think, but it concerns only glass containers.--Afluegel (talk) 21:40, 14 December 2007 (UTC)


 * I agree although this should also have it's own separate article as well (possibly merged with Glass container production). There is some info in the section glass production, this should possibly be renamed to industrial glass production (since some scientific glasses are made in much smaller quantities and don't necessarily require these bulk methods) and expanded although the full ldetails of glass production should be addressed in another article. Jdrewitt (talk) 08:50, 15 December 2007 (UTC)


 * I agree.--Afluegel (talk) 11:16, 15 December 2007 (UTC)


 * Yup, that's the right approach. Glass container production shouldbe moved to glass production and repurposed to cover both. Chris Cunningham (talk) 11:55, 15 December 2007 (UTC)


 * This may take several weeks to do... Anyway, its good to start step by step--Afluegel (talk) 16:27, 15 December 2007 (UTC)


 * I have created the page glass production although it needs much more work to be applicable to all types of glass production other than glass containers Jdrewitt (talk) 11:50, 16 December 2007 (UTC)

Order of sections
I think the current order of sections could be improved. For a layman there are two ways to get familiar with the topic because it touches his/her life:


 * A phenomenological explanation of common properties and uses. Everybody is familiar with it, and gets interested to read more.
 * The historical route. It is easy for layman to understand how glass was discovered, and how the technology evolved step by step. In this way a layman also may get interested to know more.

It is not a good approach, I think, to start out with the contemporary production process, or with a full-blown scientific discussion about the nature of glass. This is rather boring stuff for somebody who reads it the first time. However, it might become interesting after knowledge about common properties, uses, or the history. - By the way, this same order of topics is also followed in many high schools because it obviously has an educational effect. I need to have something first in my hand and feel it, then follow science, technology, and economy.--Afluegel (talk) 12:08, 15 December 2007 (UTC)


 * Yep. That's why I moved the section which at least describes glass's physical properties above the others. I think the problem we have is that the physical properties section starts off with prose and then includes a large table full of facts and figures which isn't very accessible to casual readers. I think what we should do is split this section into "characteristics" (the non-technical section, at the top) and "physical properties" (the table, further down the article). Chris Cunningham (talk) 12:13, 15 December 2007 (UTC)


 * The order could definetly be improved, however the article should certainly address (in laymans terms) what glass is at the start, since the article is entitled glass it's primary goal is to describe what glass is, properties, history, production, art etc are secondary (but are important none the less. Whether a topic is boring is a matter of opinion, the prose is generally fluent and coherent which is what counts Jdrewitt (talk) 15:22, 15 December 2007 (UTC)


 * I re-ordered the sections again, the positions are however by no means necessarily optimised, so may need some more work. Jdrewitt (talk) 15:53, 15 December 2007 (UTC)


 * You are doing good work. Now the article starts off easy, but also the deeper discussion and scientific understanding have their place for the advanced reader. In addition, maybe "Colors" could be moved to "Physical properties" or another place because it is not much related to commercial glass production or to glass making in the lab. The section "Silica-free glasses" could stand on its own, it is not well suited as a sub-section under "Glass production". Silica-free glasses are a wide field that does not go well together with common silicate glasses.--Afluegel (talk) 16:24, 15 December 2007 (UTC)


 * I really don't like the colors section as it doesn't really state what the base composition is. Maybe it would be more suitable in the glass art section? I agree with your comments about Silica-free glass Jdrewitt (talk) 17:09, 15 December 2007 (UTC)


 * It may be better off being moved to glass art in its entirety. But yeah, the current ordering is a big improvement. Thanks to both of you! Chris Cunningham (talk) 18:08, 15 December 2007 (UTC)


 * Yes some of the colors relate to bottles and so should also be incorporated into the glass container production section of glass production (once the page has been created) at some point. It's nice to have others willing to help improve this article, I've been working on it for a while but it needs to be a collaboration to work so thanks to both of you too! Jdrewitt (talk) 18:16, 15 December 2007 (UTC)


 * I agree. Thanks to you too.--Afluegel (talk) 18:22, 15 December 2007 (UTC)


 * I have moved the Colors section to glass art and added a sentence in glass container production as it seems more appropriate there. Jdrewitt (talk) 19:48, 15 December 2007 (UTC)


 * After thinking about the glass colors I believe they might be placed very well in the physical properties section of the glass article for the following reasons: 1) Colors are a physical property so characteristic for glasses that they are mentioned already in the lead section. 2) Glass colors are general properties that partially belong to bottle production, partially to float glass, partially to arts, and partially to optics (e.g., filters with sharp absorption edge). 3) The making of glass colors is partially an engineering topic, partially science (e.g. red CdS glass, photochromic glasses), and partially handicraft in arts. 4) Finally, in the glass article there is not much content yet about light interaction with glass, incl. transmission, absorption, and reflection, which should be improved, I believe. - I have a nice book about glass colors from the scientific and technological standpoint. It would be easy to add more content to the glass colors section.--Afluegel (talk) 10:08, 16 December 2007 (UTC)


 * Yes there should defintley be some comments on the colours in this article, but not the long list of additives that is now in glass art. I think the scientific explanations (that you have described) belong in this article but the 'recipes' belong in glass art or glass production. Jdrewitt (talk) 10:24, 16 December 2007 (UTC)


 * All right, I will try to move a small part of the colors section to physical properties, if this is OK.--Afluegel (talk) 10:45, 16 December 2007 (UTC)


 * OK Jdrewitt (talk) 11:01, 16 December 2007 (UTC)

First paragraph
I think we need to lose the chemistry detail. While I don't believe technical detail has to be avoided in an article lead, in this case the second half of the first paragraph is really pretty opaque (no pun intended) to casual readers. Of course if it can be rewritten to be more accessible that's an even better option. Chris Cunningham (talk) 18:55, 15 December 2007 (UTC)


 * I have edited the lead section, hopefully it is more transparent now? Jdrewitt (talk) 19:32, 15 December 2007 (UTC)


 * Quite a bit better, yes. We're really getting somewhere now. Chris Cunningham (talk) 19:36, 15 December 2007 (UTC)


 * Now there is quite a technical problem in the first paragraph. Most scientists consider sol-gel glass to be really a glass, also vitreous carbon (made by pyrolysis) is considered a glass and glassy metal. In addition: What is the difference between amorphous solid and solid glass?

By the way, the classical ASTM definition goes as follows: Glass is an inorganic product of fusion which has been cooled to a rigid condition without crystallization. - At least there is no distinction between amorphous solid and glass solid.--Afluegel (talk) 20:10, 15 December 2007 (UTC)


 * The term 'glass' is generally more restricted than an amorphous solid. The key is to pick a definition and clearly state this and then be consistent.  Many people choose the definition of a glass as "an amorphous solid which exhibits a glass transition".  The ASTM definition clearly distiguishes between forming a glass by quenching (whether it be melt quenching or deposition) and by other methods such as sol-gel (which is just a ploymerisation reaction) and ion implantation.  Some academics regard 'amorphous solid', 'glass' and 'non-crystalline solid' as synonyms.  However many do not.  The more traditional concept of a glass, that is currently used in this article, is "an amorphous solid obtained by supercooling from the liquid state continuosly, i.e. without the first-order phase transition of crystallisation". In summary the term 'glass', is by convention reserved for an amorphous solid actually prepared by quenching the melt. The only mistake therefore is that maybe amorphous solids formed by vapour deposition may be classified as a glass? Jdrewitt (talk) 20:26, 15 December 2007 (UTC)


 * For the article to be neutral we can not get into a scientific dispute, but the lead section certainly is disputable, as you already said. Therefore, we could give the classical definition first, then mention sol-gel glasses (and similar "unusual" cases) and state that some scientists consider any amorphous solid to be a glass. We should not take any side.--Afluegel (talk) 20:39, 15 December 2007 (UTC)


 * I have now edited the lead section again and hopefully it clarifies the definition now. The rest of the article should now be checked for consistency in these definitions Jdrewitt (talk) 23:25, 15 December 2007 (UTC)


 * The definition reads now very well. Thank you. I think we can leave it as it is. We need to bring the first sentence under "Silica-free glasses" in line with it. - Then, in the second paragraph of the lead section are natural glasses, which could be moved as last subsection to "general properties and uses" because it is no so very important for a basic understanding. For this purpose, the section could be renamed to "general properties, uses, occurrence" or something similar. The sentence about silica-free glasses could remain in the first paragraph, or form the second paragraph on its own.--Afluegel (talk) 08:19, 16 December 2007 (UTC)


 * I did the adjustment, and moved also trinitite and beach glass accordingly.--Afluegel (talk) 19:18, 23 December 2007 (UTC)

Silica-free glasses
Carbon dioxide undergoes pressue induced amorphisation. Technically it is not a glass, but it does have the same disordered structure as a glass. For consistency this should be clarified or else be incorporated in the amorphous solids article instead. This is where strict definitions mess things up a bit since the structure of a glass and the structure of an amorphous solid are analogous Jdrewitt (talk) 20:07, 15 December 2007 (UTC)


 * The distinction between solid glass and amorphous solid is quite a mess, because I do not know how to do it in a clean way. The amorphous solid article may be merged with glass, or it may be stated in the glass article that it only considers glasses made by melting.--Afluegel (talk) 20:17, 15 December 2007 (UTC)


 * I think the only way to do this cleanly would be to suggest that CO2 has a 'glass-like' structure and then deal with the details of polyamorphisation either in a new article completely or within amorphous solid Jdrewitt (talk) 20:30, 15 December 2007 (UTC)


 * OK, you may move CO2. More important is to find a good and neutral first paragraph for the glass article.--Afluegel (talk) 20:42, 15 December 2007 (UTC)


 * Well...on second thoughts...Polyamorphism is also relevant in glasses. For example SiO2 and GeO2 undergo pressure induce co-ordination changes.  And so I think CO2 defintely still has relevance here, we just need to sort out the definition, you have some good points about this above  Jdrewitt (talk) 21:05, 15 December 2007 (UTC)

Quickly cooling or quenching required to form glass?
In a number of places, the article speaks as if rapid quenching is required to form glass, e.g. By traditional convention the term glass is reserved for an amorphous solid which has been formed by quenching a glass forming liquid (or melt) through its glass transition temperature sufficiently fast that a regular crystal lattice cannot form and Solid glass is formed by rapidly cooling (quenching) the molten glass forming material. and The standard definition of a glass (or vitreous solid) requires the solid phase to be formed by rapid melt quenching Although I know that some glasses require incredibly quick cooling (e.g. metal glasses), I'd thought that ordinary glass needed no special cooling, and in some circumstances (e.g. large telescope mirrors) cooling could occur over weeks and even months. If this is true, then perhaps these "needs to be cooled quickly" phrases should be changed to something like "needs to be cooled quickly relative to the crystallization time; although ordinary glass can be cooled quite slowly, some materials require extremely quick cooling." --Dan Griscom (talk) 00:09, 18 December 2007 (UTC)

You are right. Please go ahead and change it accordingly.--91.36.80.72 (talk) 20:00, 18 December 2007 (UTC)


 * The lead section already states that glass must be quenched sufficiently fast that a regular crystal lattice cannot form. This statement holds since the quench time must be sufficiently fast relative to the characteristic molecular relaxation time, so any timescale is valid here.  However, the other sections could probably use some clarification as you have suggested. Jdrewitt (talk) 21:14, 18 December 2007 (UTC)


 * Fixes made. Jdrewitt (talk) 21:32, 18 December 2007 (UTC)

Glass definition
I think that glass should be better defined using four approaches: The first definition is currently missing in the article, and the third and fourth are a little bit mixed.--Afluegel (talk) 21:32, 22 February 2008 (UTC)
 * Etymological definition: from glasa originating from the Germanic language family, meaning shiny, glossy and amber in the current English language. This original definition is still contained in the expression vitreous luster (from vitrum, lat. glass) for minerals, as well as in glaze and gloss.
 * Common sense definition: hard, brittle, transparent solid; The soda-lime glass specification does not belong to the common sense definition, because it is commonly only known the technical experts, i.e., it belongs to the technical definition.
 * Technical definition: amorphous silicate solid (soda-lime glass, borosilicate glass, fused silica, etc.) prepared by melting silica and other minerals, and cooling below the glass transition
 * Scientific definition: amorphous (usually inorganic) solid prepared by any method


 * I don't know about all of these definitions. I was using my dictionary as a source.  Do you have a source for four definitions of glass?  While it may not be commonly known that "common glass" is soda-lime glass, it's properties are well-known.  So, to my dictionary and to me, the common sense definition is soda-lime glass and by analogy, similar substances.  The scientific definition needs to have at least equal weight, since the whole point of an encyclopedia is to tell me what the word glass 'really' means.  I have never heard of an "etymological definition"-- maybe we could have a section about "etymology".  MisterSheik (talk) 22:35, 22 February 2008 (UTC)


 * The introduction is quite fine as it is. It just can be improved, especially for common readers that are not familiar with the topic, i.e., the educational and informative value can be improved.
 * An expression should not be explained with a more complicated expression, I mean glass should not be explained with soda-lime glass glass, but better with window glass or flat glass or container glass. Windows are very well known, as are containers and the expression flat. The technical term soda-lime glass can be introduced at a later point.
 * The technical definition goes as follows: Glass is an inorganic product of fusion which has been cooled to a rigid condition without crystallizing. (ASTM definition, 1945) In addition, according to reference 5 in the article (Vogel) most commercial glasses are silicate glasses. (Attention: The article silicate glass is currently not very good because it does not state that silicate glasses contain silica as main component.)
 * According to reference 5 in the article (Vogel), the term glass in the scientific sense is extended so as to include all amorphous (non-crystalline) solids, independently of the method of preparation. Currently, the technical definition is confused with the scientific definition. Just consider the current formulations: In the technical sense, glass is any amorphous solid, i.e., any non-crystalline solid. and In the scientific sense the term glass is often extended to all amorphous solids. One of the two sentences are not correct; they can not be valid simultaneously, as long as science and technology are not equal.
 * The etymological definition should be better formulated as etymological origin. It is given in the German article, but unfortunately, without reference. We need to look for it.
 * I think the common sense definition if given quite well in the above mentioned dictionary, but science and technology are not well understood.--Afluegel (talk) 13:35, 24 February 2008 (UTC)


 * Great work, Afluegel. I agree with you; let's replace soda-lime glass with window glass or container glass in the introduction.  While I see the difference between the two definitions, I don't see the difference between "technical definition" and "scientific definition".  Both definitions are technical and scientific, right?  What do you think of "Tenchnically, glass is any inorganic amorphous solid, although sometimes glass is restricted to material that has been prepared by....etc."?  Finally, let's for sure have a section called "Etymology" (origin is superfluous).  MisterSheik (talk) 22:27, 25 February 2008 (UTC)


 * All right, I replaced "soda-lime glass" as suggested (and I introduced it just a little later). Yes, as soon as I find the reference for etymological details, I will introduce it. The term science is oriented towards basic, true understanding, while the term technique is oriented towards application and economy. Yes, of course, the two terms are often mixed in our times because scientists have economic interests and engineers obtain very useful results if they have a deep scientific understanding of the subject matter, but nevertheless, science and technology are not the same. I hope the current edits are fine. - By the way, it does not sound good to call aluminium oxynitride or isinglass as glass types. This makes only sense in connection with the common sense definition. Otherwise, aluminium oxynitride and isinglass are certainly no glass at all because they are not amorphous. --Afluegel (talk) 11:50, 27 February 2008 (UTC)

Solid or liquid??
From reading i have done about the structure of glass, there are meny descriptions that i would say clasify it as a liquid rather than a solid, one example if a website for this is would anyone else agree? maybe a section could be added about it?


 * On the website you mentioned glass is not described as "liquid" without the terms "frozen" and "rigid". Please consider that "frozen" and "rigid" refer at the same time to a solid. I think it is important to understand that glass is certainly a solid by all common sense, but with the structure of a liquid, which is well described in the article. If you have a specific suggestion about the article improvement, please do not hesitate.--Afluegel (talk) 09:57, 8 March 2008 (UTC)


 * As Afluegel points out, the issue is already treated in the article Glass Polyamorph (talk) 19:20, 8 March 2008 (UTC)

This is just a comment based on my own experience with glass working. I believe glass is best described as a solid with a fluid structure. Like steel, a large enough piece of glass can deform "plasticly" under it's own weight; a process that increases with temperature. At normal temperatures this could take eons. Unlike steel, glass has no actual melting temperature, (never really turns to liquid), but rather acts like frozen honey, becoming more fluid, (or less viscous), as temperature increases.

The term liquid generally implies a fluid that can readily fill a container, so I think calling it that would be a bit misleading. A liquid is always a fluid, but a fluid is not always a liquid. 216.67.92.66 (talk) 22:07, 4 June 2008 (UTC) CLewis


 * That is not actually the case. Although when you form a glass from a supercooled liquid through the glass transition temperature there is a continuous increase in viscosity, the reverse does not happen when you heat up a glass.  A glass exists in a metastable state with respect to the crystalline form of the same chemical composition.  Thus, if you heat up a glass beyond its glass transition temperature, you provide the atoms with enough energy to re-arrange into the equilibrium crystalline state, you crystallise your glass and it is very much a solid.  Further heating will result in a first order phase transition from the solid to a liquid.  Polyamorph (talk) 14:38, 5 June 2008 (UTC)

Thank you very much for your response. Yes, I agree, glass at room temperature is very much a solid. I simply think a lot of people's confusion comes from the fact that we're often taught in school that, at room temperature, glass "behaves as a liquid", when in fact it does not It behaves as a solid with a "fluidic structure". I merely think "fluid" is a better description, as "fluid" can describe a soild, liquid, or gas. (But, I yield to the experts on that.) 216.67.92.66 (talk) 18:04, 5 June 2008 (UTC) CLewis


 * Thank you too for your input here. The teaching in schools that glass is and behaves as a liquid is pretty disgraceful and demonstrates the ignorance of some high school teachers.  Sorry, I didn't mean to oppose your entire comment, I was merely stating that a glass will 'melt' (i.e. undergo a 1st order phase transition at the melting temperature of the composition) like any ordinary solid.  The structure of glass is certainly disordered and represents a liquid structure frozen into the solid state.  But the fact that glass flows is clearly wrong, as you have already mentioned.  I don't think the section Glass versus a supercooled liquid adequately describes both the similarities and the clear distinction between a glass and a liquid.  The section Behavior of antique glass also attempts to dispel the myth that glass flows but I think both these sections could be made a little more coherent and readable to the layman.  Any input from yourself on these two sections would be appreciated.  Thanks Polyamorph (talk) 20:15, 5 June 2008 (UTC)

No Problem. I'm happy to put my 2 cents in. My previous statement, that glass has no actual melting point, is clearly wrong. What I should have said is that the actual meltiing point of glass does not seem to be as clearly visible as, say, steel or ice. I guess if I were to try and define "melting point", I would say it's the point at which plastic-deformation gives way to flow. Or, in other words, the point at which two pieces that are touching no longer push against each other, but begin to readily flow, (weld), together. I think that definition could possibly be able to cover all solids making a transition to liquid.

A cracked piece of glass, at room temperature, could, theoretically, deform over a long enough time span, (ie: 50 Billion years or more), but since the crack will never weld together, I say that glass, at room temperature, can not be classified as a liquid.216.67.92.66 (talk) 18:12, 6 June 2008 (UTC) CLewis

Glass is a solid, but it behaves like a liquid overtime. The proof is the Romans glassware started to deform as if it were a liquid. —Preceding unsigned comment added by 98.111.130.141 (talk) 19:45, 7 February 2010 (UTC)


 * And you have a citation to back up that (incorrect) statement? Polyamorph (talk) 20:00, 7 February 2010 (UTC)
 * I recall from my schooldesk that old windows get thicker at the bottom because of the glass flow, but. I also recall that two solids may diffuse into each other over even shorter timescale, which doesn't make them liquid. Materialscientist (talk) 22:56, 7 February 2010 (UTC)


 * Steel can be welded when still in a solid, yet highly plastic state by hammering it together. No one seems to call it a liquid until it suddenly flows freely under its own weight. (By freely, I mean normal timescale.) At what point is a melting solid considered a liquid? Zaereth (talk) 20:40, 8 February 2010 (UTC)


 * In the case of glass, the definition of Tg is often expressed as the temperature at which the shear viscosity reaches 1013 poise (see e.g. Debenedetti, P. Nature (2001) 410, 259-267). It is at this point that the glass is considered a solid. Polyamorph (talk) 09:06, 9 February 2010 (UTC)

http://en.wikipedia.org/wiki/Glass_transition makes it incredibl clear, with ample references, that glass is solid like, but that it appears not to have any phase transition when it undergoes this 'glass transition'. Since solid is a phase, calling glass a solid in the first line of the article is CLEARLY a misnomer, and a matter which is still under research. It doesnt matter what it APPEARS to be to us, this is an ENCYCLOPEDIA and shoudl be dealing in FACT, not conjecture. Whether it is dealt with in the 'physics' section is irrelevant if we LIE about it in the first line. While the matter is under scientific debate - the language used in the aforementioned article should be used - solid-like materialMycosys —Preceding undated comment added 14:37, 24 January 2012 (UTC).


 * The glass transition article is really poorly written and mis-leading and demonstrates why we do not cite individual wikipedia articles as reliable sources. The glass transition IS a phase transition, going from the supercooled liquid to the solid state. It is marked by a discontinuity in the heat capacity. Although thermodynamically it doesn't fit into either of the conventional descriptions for a 1st order or second order phase transition, it is still undeniably a transition and glass is undeniably a solid. Polyamorph (talk) 15:07, 24 January 2012 (UTC)

Behavior of Antique Glass
This is just my observation of window panes that appear to be thicker at the bottom than at the top. Many of the panes that I've seen are not very old, but they are almost always very large panes, that are much taller than they are wide. What appears to be "thicker at the bottom", I believe, is really just the glass bowing slightly under it's own poorly distributed weight, which has a lensing effect. This is more likely due to the slow relaxation of the frame that holds it, allowing it to warp slightly below half its height. It is important to understand that flexing is neither deformation nor flow, as the glass, if laid down, would immediately return to it's original flatness. 216.67.92.66 (talk) 23:35, 9 June 2008 (UTC) CLewis

+_+_: is glass a solid —Preceding unsigned comment added by 64.30.97.126 (talk) 18:59, 20 June 2008 (UTC)

Here is a new study regarding the properties of glass. To quote: "It has been known that that despite its solid appearance, glass and gels are actually in a "jammed" state of matter — somewhere between liquid and solid — that moves very slowly."

http://www.livescience.com/technology/080623-glass-wings.html

As that article states, due to the formation of icosahedrons, (pentagon shaped molecules), on the atomic scale, glass does not even resemble a liquid, nor can there be any actual flow, but rather, the atoms should rearrange to form a crystal lattice over a long enough stretch of time. The main difference between a solid and a liquid, by all common sense, is the presence of a solid surface. Deformation is the property of a solid, (a rearrangement of atoms that radiates to/from a given force equally in all directions, as if following pascal's law). Flow is the property of a liquid, (movement of atoms to/from a given force in a uniform direction). The difference is that one is contained within its structure, however fluid that structure may appear, and the other is not.

In other words, if glass window panes were liquid they would never get thicker at the bottom, (that would be deformation), they would become thinner and shorter as the material "runs", (flows), away. 216.67.92.66 (talk) 20:11, 24 June 2008 (UTC)CLewis

I agree with this. It seems the "solid vs liquid" debate, (as is the case with most semantic debates) is irrelevant, but worth mentioning because of the prevalence of classroom meme about "old glass melting". In addition, I would suggest removing the statement "To observe window glass flowing as liquid at room temperature we would have to wait a much longer time than any human can exist." It is not cites, and most experts now conclude that even old glass does not "melt". --Axcelis555 (talk) 07:29, 3 December 2010 (UTC)


 * I agree, and I am going to shorten the paragraph accordingly. -- Marie Poise (talk) 13:15, 3 December 2010 (UTC)

New study about glass
http://technology.newscientist.com/article/dn14179-glasss-dual-personality-explained-at-last.html?DCMP=ILC-hmts&nsref=news1_head_dn14179

Worth a read —Preceding unsigned comment added by 86.121.68.72 (talk) 09:16, 23 June 2008 (UTC)
 * Another reports that using special particles called colloids that mimic atoms enabled observation of the icosahedral properties of glass, as postulated in the 1950s by Sir Charles Frank of the Physics Department at Bristol University. Pawyilee (talk) 16:07, 24 June 2008 (UTC)

Some mistakes in formatting
Exactly what the title says, the page has been sabotaged and has subsequently screwed up. I'm not a savvy enough formatter to figure it out. —Preceding unsigned comment added by Tinnalach (talk • contribs) 10:50, 23 June 2008 (UTC)


 * Thanks, I have made some fixes, as have some other users who revert vandalism. If you notice anything wrong with the current formatting then, either fix it if you can or please post it here and someone will fix it for you.  Many thanks.  Polyamorph (talk) 08:38, 25 June 2008 (UTC)

Glass versus a Supercooled Liquid
If everyone can agree that glass meets wikipedia's definition of a solid, (eg: it "resists deformation and changes in volume"), I suggest making the following changes to help emphasise this while still maintaining a neutral viewpoint.

The opening sentence of the first paragraph and the third paragraph seem redundent. I suggest changing Paragraph 1/Line 1 to:

Glass is generally classed as an amorphous solid rather than a liquid. Although both views can be justified, glass displays all the mechanical properties of a solid. The notion that glass flows to ...

The second sentence in Paragraph 3 is also a bit confusing. I suggest changing both Line 1 and Line 2 to:

Although the atomic structure of glass shares characteristics of the structure in a supercooled liquid, glass tends to behave as a solid below its glass transition temperature. A supercooled liquid behaves as a liquid, but it is below the freezing point of the material, and will crystallize almost instantly if a crystal is added as a core.

I think these simple changes may help clarify this section 216.67.92.66 (talk) 17:39, 31 July 2008 (UTC) CLewis


 * Please go ahead and make these changes, they help to clarify the points.  However, I am not very comfortable with the current statement that suggests both views (liquid or solid) can be justified, glass is a solid and if we could remove this disambiguity then I think that would also improve the article Polyamorph (talk) 17:55, 31 July 2008 (UTC)

I agree. Then perhaps I should change "Although both views can be justified" to "Although it may be possible to justify both views, ..." This sounds less definitive. Or maybe remove it altogether. 216.67.92.66 (talk) 18:30, 31 July 2008 (UTC) CLewis


 * I'm leaning towards removing it altogether! Polyamorph (talk) 19:07, 31 July 2008 (UTC)

The changes have been made. Please proofread for possible spelling and grammer errors I may have missed.. 216.67.92.66 (talk) 19:24, 31 July 2008 (UTC) CLewis


 * Looks good to me, thanks. Polyamorph (talk) 20:35, 31 July 2008 (UTC)

Glass history
What do you think about combining the sections "Glass production history" and "History"? At least some facts are mentioned two times.--Afluegel (talk) 08:24, 10 August 2008 (UTC)


 * Yes, I think the information in the "glass production history" list should be removed, converted to prose (lists are not desirable) and incorporated into the "History" section. Polyamorph (talk) 14:55, 17 August 2008 (UTC)

Physical properties, Heat capacity
Heat capacity is given as J/(mol·K). To be useful, it should either be in J/(g·K) or there should be another line in the properties table for Molar mass in g/mol so that the Heat capacity can be converted to J/(g·K). For example, if I want to know how much energy it will take to raise the temperature of a 20 oz glass bottle by 10 degrees F, I can't do it based on the information in this article. The original source for the Physical properties probably has the necessary info on Molar mass.

This article http://en.wikipedia.org/wiki/Specific_heat_capacity does have the Heat capacity in the useful form for some types of glass: Glass, silica solid 0.84 J/(g·K) Glass, crown solid 0.67 J/(g·K) Glass, flint solid 0.503 J/(g·K) Glass, pyrex solid 0.753 J/(g·K) Quisicaluser (talk) 16:09, 15 August 2008 (UTC)


 * You may find useful information in SciGlass, the source that was used for many data in the table. There is a free trial version available at http://www.sciglass.info/ --Afluegel (talk) 19:08, 18 August 2008 (UTC)

new shapes
At A&F Greenhouse technology, a new shape for windows has been designed which reduces the amount of incoming solar rays being reflected. The shape is "Zigzag" (crosswise?) and has been implemented with a variation of several centimeters aswell as microscale "zigzag"s (20 micrometers). The last type is called "Micro-V". The corners are set at 48 degrees. It may be implemented in greenhouses and regular buildings/dwellings. The windows may also generate electricity (46kwH per m²). Estimated price is 500 euro/m². Main designer was Piet Sonneveld.

Please include in article. Thanks, 81.245.170.142 (talk) 17:54, 30 August 2008 (UTC)


 * The information doesn't belong in this article, the article Window would be more suitable. Polyamorph (talk) 19:55, 31 August 2008 (UTC)

Behavior of Antique Glass - Timescale
Correct me if I'm wrong, but the references here to timescale appears to be describing Reynold's Numbers, (ie:at what scale does viscosity overcome shear, or visa-versa). The question becomes at what scale does glass begin to take on the "apparent" characteristics of a liquid, with the answer being: Infinitely Large. By the same arguement, on the small scale of a bumblebee, air begins to take on the "apparent" characteristics of a liquid, (ie: a bee can fly because it is literally swimming through the air, but if it were much larger it most certainly could not fly at all). While both of these views may be justfiable as "uncommon sense", they do not change the fact that air is still a gas (ie: it will always fill all spaces of a container), and that glass is a solid, (it can be broken). A link from here to the Wikipedia article on Reynold's Numbers may help to explain this concept more thoroughlyZaereth (talk) 01:27, 30 September 2008 (UTC)

I may have spoke too soon. After reading that article I find that you would have to be Einstein to know what it's talking about. I'll go over there and see what I can do to help Zaereth (talk) 17:06, 2 October 2008 (UTC)

history of glass
here are some refs The history section should be re-done by time frame and area.J8079s (talk) 00:15, 6 November 2008 (UTC)
 * Glass: a World History Macfarlane and Martin ISBN 0226500284
 * Sasanian and Post-Sasnian Glass in the Corning Museum of Glass Whitehouse and Brill ISBN 0872901580


 * I personally don't have access to these references. If you are able to help out with this though, by all means be bold and edit the article accordingly. Polyamorph (talk) 11:16, 6 November 2008 (UTC)

Electrical Resistivity
The electrical resistivity quoted is:

(108.5 vs 106.5 ohm/cm, DC at 250°C)

Well someone should check the units in this equation (probably: giga ohm/cm) because, to me, this makes no sense. Alain Michaud (talk) 15:45, 24 March 2010 (UTC)


 * According to the source, page 158, the numbers should be 108.5 and 106.5. I'll go ahead and fix it. Zaereth (talk) 16:45, 24 March 2010 (UTC)

Google books

 * Cultures of Glass Architecture - Hisham Elkadi
 * Introduction to Glass Science and Technology - J. E. Shelby
 * Glass And Glassware - Helen Mary Lehmann
 * Glass and Glass Manufacture - Percival Marson
 * Handbook of Glass in Construction - Joseph S. Amstock
 * Roman Glass - Stuart James Fleming
 * Glass - Eric Le Bourhis
 * Glass Manufacture - Walter Rosenhain
 * Glass and Glassmaking - Roger Dodsworth

--Stone (talk) 15:02, 25 January 2009 (UTC)


 * Thanks, but none of those links work. Also is there something you are trying to tell us? Thanks. Polyamorph (talk) 15:41, 25 January 2009 (UTC)


 * Now they should work. It was a copy past error. Most of the books have only partly access.--Stone (talk) 15:51, 25 January 2009 (UTC)

One more: --Stone (talk) 19:10, 25 January 2009 (UTC)
 * Schott Guide to Glass - Heinz G. Pfaender

Devitrification
I just came across this article, which has been written by a single editor & could use some references to improve it. Can someone who understands this have a look? Thanks, Mattopaedia (talk) 11:15, 4 February 2009 (UTC)


 * Thank you. I just placed a stub template on the page. In addition, the article is really in need of an expert; I think it was written by an artist with not much engineering experience. Devitrivication is not only relevant in glass art. Therefore, I also placed an expert-stub there. Hopefully this will help after a while. --Afluegel (talk) 22:30, 7 February 2009 (UTC)

Pre-Project Glass
Hi, I just started a small project page about the topic glass. Please feel free to contribute... --Afluegel (talk) 22:07, 6 February 2009 (UTC)
 * I wonder if there is sufficient need or support for a full blown WikiProject. Perhaps a Task Force of WikiProject Chemistry would be a better start because there are many failed or stalled WikiProjects that might still be active as a task force. May I suggest that you make the proposal for either at the WikiProject Council/Proposals because that is the place to see if there is sufficient support for the idea and where you can get feedback about its possible viability. ww2censor (talk) 15:17, 28 February 2009 (UTC)
 * Thank you. I just submitted a proposal for a task force or a work group at WikiProject Council/Proposals --Afluegel (talk) 20:58, 28 February 2009 (UTC)

Hebron glass GA
Hebron glass is not as prominent as say Roman glass or Anglo-Saxon glass, but it is (was) famous throughout the Arab world and noted by Western travelers. We in WikiProject Palestine have discussed whether to nominate it for GA status, and we generally agree that it is of Good article quality. What do you guys think is missing? --Al Ameer son (talk) 21:20, 15 February 2009 (UTC)


 * In the article Glassblowing I can read under the section Origins that this revolutionary technique was invented by the Phoenicians somewhere along the Syro-Palestinian coast around 50 B.C. In the article Hebron glass it is stated that the glass industry was established in the Palestinian region during Roman rule, starting at 63 B.C. - In my opinion, the invention of glassblowing is so important that a possible connection between these events should be discussed in the article Hebron glass. -- Afluegel (talk) 20:59, 16 February 2009 (UTC)


 * Well, I do see a reference there to the Phoenicians under the "Production" section. The article looks to be well sourced and concise, and fairly well written. There are a few errors in the "Historical" section, mostly regarding style, which I might point out. The second and third paragraphs of this section are covering the exact same point, and should be one paragraph. The first line in the third paragraph states there were "no less than fourteen glass factories of glass". Unless the factories were actually made of glass, (which they may have been, I don't know), this appears to be either a typo or a redundency. There is a line in the second paragraph where I believe the word "posits" has been used incorrectly, (posit meaning: to place something somewhere. ie: "I posit my hand on your shoulder, as a sign of frindship."), but I may also be wrong. The only other problem I see is the quote from Robert Sears in the last paragraph. A sentence in a quote should be given in its entirety, especially if there is more than one sentence. If something is omitted from the quote, then brackets, [], should be placed within the quote where the omitted information was, often with a word or phrase that can be used in place of the omission, (ie: Al Ameer son said above, "Hebron glass is not as prominent as say [other types], but it is (was) famous throughout the Arab world and noted by Western travelers.") Otherwise, so far, I don't see anything else that might cause a problem as far as style is concerned. Zaereth (talk) 22:56, 16 February 2009 (UTC)


 * I have transfered a copy of the above discussion to Talk:Hebron glass, as further discussion regarding that article should take place there. I wonder, however, if the information contained in that article, and some of its sources, could be used to help add to the "Islamic world" subsection section of this article? I notice there are a few "citation needed" flags there.Zaereth (talk) 01:23, 17 February 2009 (UTC)

Recent edits
This article has been edited substantially by Logger9 in the past day or so. Although I am delighted that interest is being shown in the article, I do not believe the edits are in the article's best interest. The most substantial edits are shown by this Diff. Although users are welcome to add new content to the article, these contributions read like a graduate level text book and are not, in my opinion, suitable for wikipedia. I have moved the section written on vitrification to the Vitreous article and removed some other sections which, although cited, were far too technical for wikipedia. I also have concern about content which is being repeatedly added that repeats information already given (content I recognise as having written myself infact) and POV content with absolutely no citations - this I have also removed. I have just discovered that the section on Sol-Gel technology is simply a cut and paste job fromt he Sol-Gel article! I do not want to put any user off editing this article but I really can't see these edits as being productive. More over I'm having to wast my time having to fix all the problems with them. Polyamorph (talk) 08:42, 14 March 2009 (UTC)


 * Right the Sol-gel section has now just been added straight back in - even with my main template removed - could somebody else fix this please. It is an exact copy of the material in the Sol-gel article. Polyamorph (talk) 09:32, 14 March 2009 (UTC)


 * As has all the other stuff which is also replicated by the same author at Vitrification. Polyamorph (talk) 09:46, 14 March 2009 (UTC)


 * I reverted this one last time - I have tried to incorporte some of the useful content added into the article where possible but much of it is unsuitable. Polyamorph (talk) 09:57, 14 March 2009 (UTC)


 * A substantial amount of what Logger9 added, which for now I have left in, is taken from the Transparent materials article. Polyamorph (talk) 10:11, 14 March 2009 (UTC)


 * Thank you for all the efforts! I hope that any disagreements can be resolved here on this talk page, not in the main article.--Afluegel (talk) 20:32, 14 March 2009 (UTC)


 * Hello there. I was one of the people that first helped ease logger into Wikipedia. While the information may be quite technical, I just wanted to remind you to please act in a manner that does promotes good relations between Wikipedians. Transparent materials was twice deleted for various reasons and redirected as you guys did, but is now a fairly decent article. I'll try to see if I can get logger9 to participate in a discussion here on why he feels his information should be added. I believe he is a professor, which is why his material may be a bit advice. Please remember though, that he is acting in good faith and just feels a bit frustrated now, as much of his work has been deleted. NuclearWarfare  ( Talk ) 21:25, 14 March 2009 (UTC)


 * So copy and pasting large parts from other articles is ok? I for one have noticed text that I have written (relating to the physics of glass) being added all over the place by this user - this is wrong - the constant copy and pasting of the information in Sol-gel into multiple articles is wrong - the original authors deserve credit and this is infact required by the GFDL. The user has been warned about this before. Academic credentials don't mean much if the user cannot cite reliable sources for controversial claims such as the liquid nature of glass. Infact complete laymans can edit wikipedia and manage to do so and follow the correct policies and add reliable sources and reliable information. So saying someone is a professor is just saying they MUST know better than anyone else - in fact this is very rarely the case. This article could well do with well researched reliable and cited information. However, we are not here to publish anybody's personal essays or allow them to copy and paste other peoples work which already exists in wikipedia. Good faith edits does not necessarily mean good edits. Polyamorph (talk) 21:40, 14 March 2009 (UTC)


 * Well, as for the copy and paste...logger9 wrote all of the initial information. If he copied and pasted information and violated the GFDL, isn't educating him a better thing to do instead. If he is a professor (and does not seem to pushing any fringe theory, which does not seem to be the case), I'm sure he'll pick it up. Also he did seem to cite reliable source information; he just added it in the form of books and did not cite everything inline. In any case, he emailed me to said he would follow up on the discussion below, so I'll back out and stop putting words in his mouth, though I shall keep this discussion watchlisted. NuclearWarfare  ( Talk ) 21:48, 14 March 2009 (UTC)


 * I'm sorry but that is false - logger9 didn't write the material I wrote on the physics of glass - they used exactly my words in a number of articles except left out all the citations. I also find it hard to believe that they wrote everything in Sol-gel, the edit histroy suggests otherwise. So plain and simply that is false. Yes education is the best way forward but after posting on their talk page I got and have still had no response - I have explained every one of my actions here for all to see and used extensive edit summaries when I have had to alter their edits and also explained these on logger9 talk page. There is no more I can do so don't expect me to. Polyamorph (talk) 22:07, 14 March 2009 (UTC)
 * He had written Transparent materials though, which is what I had thought you were talking about. NuclearWarfare  ( Talk ) 22:30, 14 March 2009 (UTC)
 * No, I was for instance talking about the duplication of Sol-gel into this article and many others. And the duplication of material from Glass into other articles, e.g. Vitrification. Polyamorph (talk) 22:36, 14 March 2009 (UTC)

FYI: The bulk of the "Sol-gel" article was written by me -- especially the introductory paragraphs that were initially transferred to the Glass page. I do not understand why you are so intensely resistant to having a brief descrption of that cutting edge topic on the Glass page.

logger9 (talk) 01:36, 16 March 2009 (UTC)


 * By the way - the solution is simple - if Logger9 comes to this talk page as they have been advised at least twice, then we will discuss their work and find a way to help them incorporate their useful information - however if they do not wish to enter into dialogue with us then we can not fix anything - I for one do not want these issues to be fought over in the mainspace - rather lets discuss what needs doing and try and fix it together. The article is by no means complete and needs reliable information to expand it - however we must still have some form of quality control and that can be achieved through consensus here. Polyamorph (talk) 22:21, 14 March 2009 (UTC)
 * His exact words to me from an hour or so ago: "...and I will follow up on the "Glass" discussion page". Posted with permission So he should be here. NuclearWarfare  ( Talk ) 22:30, 14 March 2009 (UTC)

Large additions by logger9
Best to start a new discussion, I believe NuclearWarfare  ( Talk ) 21:25, 14 March 2009 (UTC)

Physics of Glass

Agree: "The standard definition of a glass (or vitreous solid) is a solid formed by rapid quenching from the fluid molten state. If the cooling is sufficiently rapid (relative to the characteristic time of crystallization time) then crystallization is prevented. Alternatively, the disordered atomic or molecular configuration of the supercooled liquid is frozen into the solid state at the glass transition temperature Tg.

"Generally, the structure of a glass exists in a metastable state with respect to its crystalline form. As in other amorphous solids, the atomic or molecular structure of a glass lacks any long range translational periodicity. However, due to chemical bonding characteristics glasses do possess a high degree of short-range order with respect to local molecular polyhedra. Thus, glasses are generally classed as amorphous solids rather than a liquids, especially since they display many of the mechanical properties of a solid on the most easily realized time scales."

Disagree: "The notion that glass flows to an appreciable extent over extended periods of time is not supported by empirical research or theoretical analysis. From a more commonsense point of view, glass should be considered a solid since it is rigid according to everyday experience."

-

While I respect the author's position, I must point out that what he/she has done here is to step into the middle of an ongoing debate within the community of Condensed Matter Physics and choose a side which is not only immediately appealling to the simplest mind, but even experimentally verfiable on the simplest timescales.


 * There is no one author responsible for the Glass article and its content is the result of collaboration, although in places certain sections may be authored by one or few people in general many people have edited all parts of the article. Hence what is written is the current consensus, as discussed on this very talk page (Scroll to the top) and in the archives. Polyamorph (talk) 15:09, 15 March 2009 (UTC)

It is however, essential to realize that it is inevitably the natural tendency of most amorphous solids (or glasses) to move towards their equilibrium crystalline structure -- on geologic timescales. This essentially constitutes their non-equilibrium supercooled liquid state. Both in a glass and in a crystal it is primarily their vibrational degrees of freedom that remain active. Other rotational and translational motion becomes limited strictly to long-range occurrence and activation over millennia.


 * What do you define as a geologic timescale? Our article states, with a reliable citation, that the relaxation time of GeO2 (a structural analogue of silica) is greater than the age of the universe - this is not geologic timescale - this is forever! which ultimately means the relaxation does not ever take place. In the presence of heat and chemical interactions, yes I can see a glass crystallising - but sitting on its own over all the time in the universe it will not. Polyamorph (talk) 15:09, 15 March 2009 (UTC)
 * Oh and you say a glass is in non-equilibrium supercooled liquid state but you have already admitted that you 'believe' in the glass transition which is what marks the supercooled liquid from a solid - its all explained in the article (maybe not brilliantly but work needs to be done on it) so I don't need to explain here but you are contradicting yourself by saying you agree with the existence of Tg (although it would be impossible not to agree with its existence since it can be so readily observed and measured) and then going on to define glass as a supercooled liquid. This is the most controversial part of you contributions, you really need to be clearer in what you mean and present the evidence so that maybe we can actually believe it. Polyamorph (talk) 15:19, 15 March 2009 (UTC)

These arguments are largely academic -- and highly respected within the vast majority of the scientific community. The only empirical proof I can currently see in the literature is that relating to recent work on quasi-elastic (inelastic) light scattering in glasses.

"On the Origin of Quasi-Elastic Light Scattering in Glasses"

Europhys. Lett., Vol. 57, p.838 (2002)

"Very Low Frequency Raman Scattering in Vitreous Silica"

Phys. Rev. B, Vol.12, p.2432 (1975)

"Low-Temperature Specific Heat and Thermal Conductivity of Non-Crystalline Solids"

Phys. Rev. Lett., Vol.27, p.1280 (1971)

The net result of these works is the clear presence of the dynamic non-equilibrium behavior of non-crystalline silica (the most basic glass former known) at the molecular level. This would indicate some degree of irreversible plastic (structural) deformation -- and flow -- on the smallest spatial scales. The net result of this over time would be irreversible plastic deformation (and flow) on continuously larger spatial scales.


 * Dynamic non-equlibrium behaviour - so you are saying there are phonon interactions - vibrations of the glassy matrix? It is only flow if the atoms move from one position to another and then do not return to their original position. I don't know enough about it but I don't think what you are saying is justifiable evidence that glass flows - and if it is then YOU need to explain it such that the layman can understand because I certainly don't know what you are talking about and I have expertise in the structure of glass. Polyamorph (talk) 15:09, 15 March 2009 (UTC)

Thus, the supercooled liquid definition of glass is not to be taken lightly. It has been the core of the explanation of the glass transition since long before I was in the educational system. The work that I submitted to the "Glass" article represents a number of years of work I was able to complete in my post-graduate years in Materials Science and Engineering, while spending the majority of my time in the University of Washington Physics Library.


 * You should not be submitting your personal essays for publication on wikipedia. Polyamorph (talk) 15:09, 15 March 2009 (UTC)

I understand if some of it needs to be rephrased to fit the style which you require. In fact, I would encourage it! This was done quite successfuly with my original article on "Colloidal Crystals" (see discussion). You were also most patient with me when I attempted to create an article on "Transparent materials" from scratch, while my work on "Sol-gel" science seems to have been readily accepted.


 * If there is any rephrasing to be done then you should not expect others to do this for you. Just because you have gotten away with it before in Transparent materials doesn;t mean you can here. Did you write the article on Sol-gel? That would explain why you are persistently adding to this and other articles. You must stop doing that, just link to the articles in question, there is no need to repeat content that is already addressed in detail in other articles. Polyamorph (talk) 15:09, 15 March 2009 (UTC)

But to refute this work is to refute the basic facts as presented (and widely accepted) within the scientific community. All of this information is based on clearly referenced work which has been published worldwide in the most reputable physics literature.


 * No one is refuting your work - just the way you are going about trying to it noticed! Polyamorph (talk) 15:09, 15 March 2009 (UTC)

I sincerely believe that it belongs on the "Glass" page under the "Physics of glass", and makes a glove fit with the work that is already published there. I.E. Both sides of the argument should be presented clearly. Then let the reader make their own educated decision. But at least give them the facts -- in order to fuel their unbiased thinking process !

In addition to the history of glassmaking, I believe that the educated reader in an emerging technologically advanced society should be aware of the physical mechanisms of how the stuff works -- as established by accepted scientific authorities in the field.


 * All aspects of glass science and technology should have equal weighting in this article. The article should not be weighted to one persons own biased interests and opinions. Polyamorph (talk) 15:09, 15 March 2009 (UTC)

logger9 (talk) 23:01, 14 March 2009 (UTC)


 * So you have just gone ahead and added all your stuff back in regardless of what has been discussed on this talk page. First we need to gain consensus on what is right and what is not. It is clear though that copy and pasting your extensive essays - which you have admitted are student essays - is wrong and you should STOP this immediately. It is also clear that copy and pasting material from other articles into this one (e.g. Sol-gel) and vice versa is wrong and you should STOP doing this immediately. Once you start working with us, we can work with you. But repeatedly adding content to wikipedia, even when you have been asked not to and without proper discussion here FIRST is not going to get us anywhere. Right now, the academic points you make are not the primary concern. The primary concern is the nature of your contributions which currently go against wikipedia policy. Polyamorph (talk) 11:05, 15 March 2009 (UTC)


 * Logger9 should not just add his stuff without explanation and without willingness for co-operation. This is not very constructive.--Afluegel (talk) 13:07, 15 March 2009 (UTC)


 * OK, I just reverted all recent edits by Logger9. There needs to be a discussion first here on this discussion page, or at least the edits should have an edit summary.--Afluegel (talk) 13:16, 15 March 2009 (UTC)


 * Edit summaries would certainly be welcome! But so too would discussion first BEFORE any further extensive edits - we are happy to discuss this and have opened all channels to do so - we are not critisising Logger9's work or saying that they are wrong - we are just saying that the problems that have been highlighted numerous times should be sorted out here and not in the mainspace! Polyamorph (talk) 13:26, 15 March 2009 (UTC)


 * Sure, Logger9 might have some good points, but with the help of a little discussion and co-operation it would be good to find this out. Two minor points about the introduction:
 * Why Logger9 moved the images around in such an unusual way that empty space was forming in the text?
 * How can "glass" be explaned right away in the first sentence with "amorphous solid"? A term can not be "explained" by a more complicated term, especially not for a layman. Not all readers are professors. Later on in the article it is already stated, that in the scientific sense glass sometimes encompasses all amorphous solids, but this is only the definition for some scientists (not all), and certainly not for a layman. --Afluegel (talk) 13:47, 15 March 2009 (UTC)

OK, folks. Sorry if I have stepped on any toes. You have my work. Feel free to use it....or feel free not to. It's your show, and it continues to be an immense asset for me in teaching the basic sciences.

As far as anything I have "gotten away with" once again, I apologize for the inconvenience.

Good luck with it :-)

logger9 (talk) 18:38, 15 March 2009 (UTC)


 * Dear Logger9, thank you for your feedback. It was not the meaning of this discussion, however, to either take all your edits as they are or nothing at all. Anybody can make errors now and then, including you and me or other editors of the glass article. What do you think about the comments to your edits and comments given above? In a beneficial co-operation some patience and compromises are necessary. "Our show" or "my show" are not appropriate in a co-operation. Also successful teachers and scientists still need to learn. I apologize, if you might have understood it differently, and I am looking forward to further edits from you of the glass article. All the best also with your mathematics and chemistry teaching... -- Afluegel (talk) 20:54, 15 March 2009 (UTC)

You may be looking forward to further edits, but jdrewitt clearly is not. It would appear that I have trespassed on his/her territory. Half of the comments are fairly hostile.

I have now put in a full weekend of work on this project, only to have it tossed out in its entirety. I am already falling behind in my grading -- so I need to catch up. This is extremely distracting for an upcoming work week. You are catching me in the middle of preparing a major departmental presentation on the Chemical Processing of High Performance Materials.

I will try to get back to you on the educational front. Dynamic Light Scattering (DLS) is not everone's cup of tea -- but it can give invaluable information w/r/to the higher frequency (shorter wavelength) dynamics of liquids and solids. Ultrasonics have also taught us a lot in this area (see references to the Catholic University of America).

In the meantime, I would suggest cleaning up my work to your preferred style and reposting it. I.E. I see my job as giving you the information. You can decide how it is to be presented. I seriously doubt that I will object to anything you come up with -- as long as the majority of the intellectual content stands.

Does that sound reasonable enough for now ? Again, sorry about the trouble -- and thanks immensely for getting back to me on this :-)

logger9 (talk) 22:24, 15 March 2009 (UTC)

You wrote: "The problem is that you first made substantial edits without explanation, then they were re-worked substantially by Jdrewitt and you just reverted them, without getting into discussion with him in detail."

Please correct me if I am wrong -- but none of the following work has ever even been discussed (much less re-worked "substantially").

1) Viscosity of simple fluids

2) Structural relaxation

3) Viscoelastic behavior

4) Vitrification

As the bulk of my work in glass physics, it has simply been dismissed by Wiki author jdrewitt as "far too long, entirely uncited, repeats information already given, is too technical, might even have some aspects of original research and in places is incorrect."

I don't see this sort of input as constructive in any way shape or form. There is no hint of compromise or negotiation in the tone of the script. And some of it is simply not true.

logger9 (talk) 00:33, 16 March 2009 (UTC)


 * I am sorry about all the misunderstandings and the trouble it has caused you. I think through your user subpage Physics of Glass discussed below we will soon come to a satisfactory solution for everybody.--Afluegel (talk) 07:39, 16 March 2009 (UTC)


 * I too am sorry about the misunderstandings and the perceived hostile nature of my comments - it is more frustration than hostility - your contributions are welcome but we need to find a way that is suitable to include them here without compromising the quality of wikipedia - I don't need to make an issue of this though as I am delighted we seem to have moved on from this and are collaborating effectively below. Polyamorph (talk) 09:15, 16 March 2009 (UTC)

Physical properties table
I have thought about the physical properties table that is currently in the article and am thinking that it might be better to move this to its own page, e.g. List of physical properties of glass or something like that. Only as it is, the table takes up a lot of space in the article and is not as exhaustive as it perhaps could be. Having its own page would help to fix these issues I think. We can still have the section entitled Physical properties but then just link to this table on its new page. Comments welcome. Polyamorph (talk) 09:15, 14 March 2009 (UTC)


 * OK, I think it is a good idea. At this occasion, it might be beneficial to compare the values to the original entries just for safety reasons. I did not realize it, but it might well be possible that a value got changed by accident.--Afluegel (talk) 20:26, 14 March 2009 (UTC)


 * OK, well there is no rush, if I get chance I'll try and do this sometime, maybe more glass compositions can be added having the properties in the columns and compositions in rows. There might be a way to shrink the table to get more information in or make the table more readable? I'm also thinking a separate page would enable us to add some nice looking plots of the different properties, without going too overboard, but it has potential to be a good reference page. Polyamorph (talk) 22:32, 14 March 2009 (UTC)


 * You may find some very useful information on optical properties located at the following website:
 * http://www.harricksci.com/infoserver/Optical%20Materials.cfm
 * I hope this helps !
 * logger9 (talk) 01:22, 15 March 2009 (UTC)
 * Your harricksci link is broken, where'd it go? --Vaughan Pratt (talk) 20:02, 12 November 2009 (UTC)


 * Yes that's the sort of thing we want, but all on one page. And rather than saying "This was compiled from various sources" we have to cite the actual sources on wikipedia. Polyamorph (talk) 14:05, 15 March 2009 (UTC)


 * Finally I have had some time to do this and have moved the table to the new page List of physical properties of glass. Hopefully this way the table can be expanded to incorporate many more useful common glass compositions. Polyamorph (talk) 16:21, 9 October 2009 (UTC)
 * Fantastic, thanks. But given that one application for glass is in windows, shouldn't there be data about other than merely refractive index?  For example how transparent is glass, as a function of light wavelength from UV to far IR, glass thickness, and glass composition?  Or is transparency a sufficiently central physical property of glass that it deserves its own article?  --Vaughan Pratt (talk) 20:00, 12 November 2009 (UTC)
 * Actually, including some info about the transmittance of glasses sounds like a great idea to me, since this info is very useful in laser construction. However, information I've seen, from such places as CVI Laser Optics, indicates the transmittance is not usually constant, but often varies with wavelength, so the actual transmittance of a substrate may be difficult to explain without graphs. Zaereth (talk) 20:39, 12 November 2009 (UTC)
 * I finaly found it. This was difficult to find on their site, and not as detailed as the graphs in my hardcover cat, but basically spells out the "usable" transmission range for various glasses. So this may be better for our purposes, but may not include types like soda-lime. http://www.cvilaser.com/Common/PDFs/CVI_Optical_Materials.pdf Hope that helps. According to the line graphs, "usable transmission" typically means from 80 to ~90% for a 10mm thickness and 0 degree incidence angle, without antireflection coatings.Zaereth (talk) 18:01, 13 November 2009 (UTC)

Logger9: Physics of Glass
In order to present my material in a manner which can be openly perused and freely discussed by all interested parties, I have been advised by helpful Wiki associates to create a user subpage. Please rest assured that had I been aware of this procedure, I would have gone about this whole thing in an entirley different manner.

Furthermore, I wish to extend my most sincere apologies to any and all Wiki staff and authors whom I may have offended in any way in the course of my recent actions. I can assure you that this was certainly not my intention. Since my original article on Colloidal Crystals was posted around the New Year, I have not had any serious opposition to my contributions. But this is clearly not the case (nor should I have expected it to be !) in the continuing debate over the true nature of the glassy state of matter. This is certainly one of the great unanswered questions in the field of Condensed Matter Physics.

When I was much younger, I used to feel a sense of urgency over unanswered questions which I felt I might contribute to if sufficiently driven and motivated. This passion and desire for scientific truth and knowledge was amplified considerabaly by a relentless Turkish advisor (current Director/Princeton Materials Institute) while I was under full fellowship from the State of California.

In my post-graduate years, I spent several months working for a major think tank (IBM TJ Watson Research Center, Ceramic Sciences Division) where I was focused on the synthesis and application of crystalline and glassy thin films and coatings. I used the money I earned that summer to spend another year or so in the university environment of UW (Seattle) where I could pursue my own interests academically. This work is essentially the distillation of much of my efforts in those years.

Please feel free to let me know what you think of my work -- and more importantly what you perceive to be its potential role in the Wikipedia archives of published literature. *Note the absence of any section(s) on physical properties -- yet.

logger9 (talk) 04:34, 16 March 2009 (UTC)


 * Thank you very much for your discussion and the creation of your subpage Physics of Glass. If you do not mind, I inserted the link to it right in the headline of this discussion, so it is easier accessible for everybody right away. Personally, I would need a few days to digest its content and to form an opinion. At first sight, the introduction looks technically all right and very interesting, except, that a few links to other articles at Wikipedia could be inserted, and "on geologic timescales" could be removed because "the natural tendency to move towards their equilibrium crystalline structure" always exists for thermodynamic reasons. Please correct me, if I am wrong. Further comments will follow later.--Afluegel (talk) 05:40, 16 March 2009 (UTC)


 * Thanks much for the linkage !


 * Your thermodynamic argument is impeccably correct. And I agree that we could remove the reference to geologic timescales. But I do not see the reason for doing so. It is there intentionally to make clear to the reader that glasses do not behave as classical liquids. They move more glacially. -- logger9 (talk) 06:10, 16 March 2009 (UTC)


 * OK, this is fine with me. Please give me some time to read also the rest of your article. I am happy about your intention to contribute to the glass subject.--Afluegel (talk) 07:31, 16 March 2009 (UTC)


 * That sounds great. In the meantime, I will try to go through it to bracket more internal (Wiki) links. And if for some reason they get clipped later, that's OK, too. -- logger9 (talk) 08:35, 16 March 2009 (UTC)


 * Thank you very much for doing this Logger9 - hopefully this will be a much more productive way of doing things for all involved. I too need some time before I make comments on the work but thanks for giving us the opportubity to move on. Polyamorph (talk) 09:09, 16 March 2009 (UTC)


 * Ok, I am not critisising you or your work but it still reads and looks like an essay or a section from a text book. My comment above still stands, that the primary concern is not at present the academic points. You obviously have knowledge on the subject and no one is refuting that (even if there is some disagreement). However, the fact remains that this work is simply too long and too inaccessible to the general audience - which is what wikipedia is aimed at. Please see WP:SUMMARY and WP:Article size for guidelines on this. Now it might be that the sections belong in seperate articles and we link to that page so if the reader wants to read more they can. There is no doubt that the work is an extensive review of the literature and current views on the subject. But somehow we need to make this more accessible to the general reader. At the present time the best thing to do would be to try and summarise this work considerable so we have something more managable to work with. Polyamorph (talk) 17:53, 16 March 2009 (UTC)


 * Thank you very much for your response, especially the first post. In your second (most recent) post, I appreciate your concern, and yet I do not agree with the bulk of your statement.

Length is not the important issue. The main issue is content. If the content effectively conveys the message, then there is no reason, (other than simply space saving) to eliminate valuable information. The basic ideas presented here relate to fundamental particle motion, particle interaction and particle vibration -- especially as these concepts pertain to frequency dependent phenomenon and physical properties on a wide spectrum of temporal and spatial scales.

All of these microspcopic concepts combined yield some macroscopic event which is, in this particular case, plastic deformation and viscous flow. This mode of thinking may be quite novel to the vast majority of the readers. (It certainly was an awakening for me !) Thus, I believe firmly that they need a fully detailed description in order to grasp the most essential ideas. I.E. What I am attemting to do here is teach the masses some real Solid State Physics while learning about the glass transition. For those not well-versed in this field (which is about 99.9% of the human population) this simply cannot be done in several paragraphs.

I privately tutor Advanced Placement high school kids who I believe could have graduated from college with a Bachelor's Degree in the 8th or 9th grade. I believe that most educated people in the modern world have the capacity to understand much of what has been denied them in the past. But please do not attempt to sell them short for the simple purpose of saving cyber space in your Glass article. Then they don't have a fighting chance. -- logger9 (talk) 18:23, 16 March 2009 (UTC)


 * I am simply going by what is written in the wikipedia guidelines I have already cited WP:Article size. i.e. long articles or sections of prose are not easy to read and it should therefore be considered whether or not to summarise (WP:SUMMARY) or split the article and wikilink appropriately.Polyamorph (talk) 18:34, 16 March 2009 (UTC)
 * Another good link is WP:NOTPAPER. Polyamorph (talk) 18:49, 16 March 2009 (UTC)


 * I am certain that it should always be considered. But in this case (for reasons including those stated above) I do not think that it should be done. -- logger9 (talk) 18:59, 16 March 2009 (UTC)


 * I really really hate quoting policy, but another good point is made here WP:NOTTEXTBOOK - I'm not making this stuff up - it is not simply my opinion - unfortunately we are not here as teachers - we just present facts. I still think there is something that can be done to help incorporate your contributions but it must be done in a way that is suitable for wikipedia as an encyclopedia and you need to appreciate this. Polyamorph (talk) 19:02, 16 March 2009 (UTC)


 * By the way, there are places where teaching material is appropriate, at wikiversity for example or wikibooks - so maybe you could summarise here and include the full content in those places? Polyamorph (talk) 19:06, 16 March 2009 (UTC)


 * I have to agree with Jdrewitt here. The text included previously is much too long and technical for the average reader. Wikipedia should be readable by adults and children, professors and laymen alike. I think the work contains useful information, but could use a lot of trimming up, and some work on style and readability. Since Wikipedia is not a text book or an instruction manual, we try to provide information in an extremely condensed and easily read format. The great thing about Wikipedia is that in line references are provided for most all claims, most of which interested people like myself can click on and read the more technical text directly. This makes it more convincing for those who are very interested, and more captivating for those who are merely browsing, or want a simple question answered. Zaereth (talk) 19:34, 16 March 2009 (UTC)


 * If there was an in line reference that I could refer to in this case, I would be more than happy to consider using it. But unfortunately, there is not. The subject matter is simply too specialized. -- logger9 (talk) 20:07, 16 March 2009 (UTC)

I found your suggestion about the wikiversity to be an intriguing one, so I checked it out as follows. I chose a random chemistry subject which I have taught in the classroom regularly, and compared the articles on both sites. It was readily apparent to me that the Wikipedia article was far more thorough, and clearly oriented towards a more intelligent audience (or one that had already recieved some minimal level of education). I have listed them both here so that you can compare for yourself.

http://en.wikipedia.org/wiki/Reaction_rates

http://en.wikiversity.org/wiki/Rates_of_Reaction_-_Kinetics

There are no articles whatsoever on the subject of "Glass" at the Wikiversity. Furthermore, if an encyclopedia is not for teaching (which is basically providing established facts and information) then I'm not really sure what it is for. -- logger9 (talk) 21:02, 16 March 2009 (UTC)


 * It isn't as established as wikipedia no but will become more so the more people who contribute to it. There is a difference between teaching and simply providing someone with the means to aquire knowledge. It is clear in the policy guidelines what is and what is not acceptable in this particular Encyclopedia and this has all been agreed by consensus. I have already said your work can potentially be included in wikipedia but only if it can be made to abide by wikipedia policy. Afluegel's points below make sense to me and are essentially WP:SUMMARY.Polyamorph (talk) 21:43, 16 March 2009 (UTC)


 * In the meantime I got a little time to read the first part of the discussed article with the title Viscosity of simple liquids. As far as I can tell, the content is certainly not easy to read, but there are other articles that are also not so easy, such as the related article Viscosity, or that are very specialized such as Glass batch. Now, because the content is so specialized, it can not be included in its entirety in the article Glass, but I do not see any reason why it should not be an article by itself for the interested reader (at least as far as I got until now, which is the viscosity section). The content makes sense, and it does not seem to be original research. In summary, it is simply explained how the viscosity can be understood based on the movement of the atoms and molecules, also termed kinetic theory. Please correct me, in case that should not be right. Because of the difficulty of the subject, the article should contain appropriate internal wikilinks where the desired explanations are given in other articles. Naturally, not all content at Wikipedia can be understandable for everybody. At least for the viscosity section, I do not see how it could be made shorter, but I think it is possible to work on the language in such a way that it is easier to read. - So far for now. I am not done yet reading the entire article, and I will give more comments later.--Afluegel (talk) 21:07, 16 March 2009 (UTC)


 * You have hit the proverbial nail square on the head!


 * Has anyone ever wondered why there is no "Maxwell's Kinetic Theory of Liquids" (or Solids -- or Glasses)? Or why there is only an effective "equation of state" for gases? It is called the Ideal gas law: PV = nRT. Have you ever thought about creating such an equation of state for liquids or solids? I won't even start that here. Even Einstein busted out on that front -- but he was far more obsessed with relativity.


 * To effectively describe the heat capacity, try creating a complete spectrum of vibrational frequencies for a perfect elemental crystalline solid (see Mott & Jones, Chapter 1). And that only holds for nearest neighbor particle-particle interactions. It is a mathematical nightmare...and you will not find it anywhere in the literature. No one has yet done it (please correct me if I'm wrong). It remains as the greatest enigma and blank space in the most comprehensive texts in the fields of physical chemistry, solid state physics, and thus Condensed Matter Physics.


 * All I am trying to do is to summarize and archive the most fundamental and insightful work that has been done in this direction. My grad school advisor would have loved to (I've seen his proposed equation of state for solids) but he simply did not have the time or the proper background. For awhile he worked with a famous statistician (Rioichi Kikuchi) who tried to help him with the math. But (in my humble opinion) it was simply unmanageable.


 * The bottom line is that the Kinetic Theory of Gases only holds for individual particles that have no interactions with other particles. It is a virtual fantasy. Even most gases exist as diatoms (e.g. H2, N2, Cl2, etc.) or even larger clusters (e.g. S2, S4, S5, S6, S8). But it is the best approximation we have. And more importantly, it makes a lot of sense when you break it down in terms of microscopic kinetic theory and the corresponding macroscopic thermodynamic variables of P, V and T.


 * So does the glass transition make sense on the same level -- as well as the general phenomenon of solidification and the order-disorder transition. Even more interesting is the subject of structural transformations in solids -- especially "military" diffusionless or martensitic transformations [] which rely on the cooperative behavior of large groups of atoms or molecules all moving simultaneously in the same direction at the same time.


 * This is what people need to understand. As materials scientists, we have no equations of state yet for condensed matter. But we do have some basic particle physics. And we also have a reasonable understanding of the normal vibrational modes in crystalline solids (Einstien, Debye, Kittel, Blackman, etc.) and the mechanisms of thermal phonon propagation as represented by the superposition of both longitudinal (or acoustic) and transverse (or optical) waves of atomic displacement (Brillouin, Kittel, etc.). In addition, with the dawn of monochromatic laser light scattering, our experimental apparatus is getting better by the day.


 * In summary, our explanation of the physics of glass is only beginning. I think it would be great to have an independent page named "Physics of glass" linked to the main page on "Glass". I would see it as privilege and an honor to be the primary author of that page. -- logger9 (talk) 22:19, 16 March 2009 (UTC)


 * I would be happy for a new page "Physics of glass" be created PROVIDED that the issues that have been raised are properly addressed at your draft page first. Polyamorph (talk) 22:46, 16 March 2009 (UTC)


 * That is the general idea :-) -- logger9 (talk) 16:55, 17 March 2009 (UTC)


 * Now I read the proposed article, and I think it is highly relevant for the topic glass. As you will recognize in the physics section of the glass article, there is the image of a question mark with the notion that the topic is still an unresolved problem. Since Logger9 wants to address the topic, I only can encourage him. Concerning the scientific content of the proposed article I do not see anything wrong or original research. However, since I am not a physicist, I placed a comment about the proposed article on the discussion page of the WikiProject Physics for getting an expert review. Hopefully this will work, but even if not, I still would suggest creating the article or at least its summary with the template underconstruction on top. This template usually prevents other editors deleting the article right away, even if it might have many shortcomings. Now about formalities: The proposed article does not have yet a summary, i.e., a few paragraphs that shortly introduce the whole content. If possible, the fist sentence could be a definition of the content, for example: "Physics of glass is the science of..." or "The nature of the vitreous state is investigated through..." or "The vitreous state is defined as..." or something similar. The title of the article should be marked fat in the first sentence. Then it is a policy at Wikipedia, that in good articles every paragraph should end with at least one reference. This also makes it very clear that the content is not the theory or the research result of the editor (original research), but it is already published somewhere. Finally, as the content is not easy to digest, it would be good to use a simple, but still scietifically correct language. For example: Mechanisms of atomic displacement or particle displacement in solids are closely related, in a structural sense, to mechanisms of viscous flow and solidification in the liquid state. could also read, I think: The mechanisms of movement of atoms (or molecules/ions) in solid materials are closely related to the mechanisms of viscous flow and solidification in liquid materials. I hope, my proposal is still correct, but for sure, it reads a little easier in my opinion. It may be advisable to contact also User:RHaworth because he initially had problems with Logger9 (I do not understad why RHaworth had the problems), that luckily appear to be resolved now. - In case the proposed article works out well, it would be a good opportunity to finally find a home for the task force Glass within the WikiProject Physics, as the Physicists would recognize quite a lot of connections, I hope. - I am looking forward to your comments.--Afluegel (talk) 17:54, 17 March 2009 (UTC)

Excellent !!!!!!

The mechanisms of atomic/molecular motion (or particle displacement) in solid materials are closely related to the mechanisms of viscous flow and solidification in liquid materials.


 * ....would allow us to retain the internal Wiki reference to particle displacement.


 * I like the idea of referencing each paragraph. I assume you relaize that this will mean multiple referencing (since some articles continue for several paragraphs). I will take care of it.


 * I think that it would be a good idea to place an internal Wiki reference to Physics of glass within the image with a question mark on the Glass page. Would that be OK ?


 * I am at work now on a new introduction, as per your well-thought suggestions above. -- logger9 (talk) 19:50, 17 March 2009 (UTC) :-)


 * OK, I left for RHaworth a comment on his discussion page, just in case their is another problem. Yes, the multiple referencing is common. I will think about the image with the question mark.--Afluegel (talk) 21:03, 17 March 2009 (UTC)


 * Yes, I think this type of language change very much improves the readability, and adding muliple references is a major plus, (even if they're all from the same source). I'll read through it all myself when I can find the time and try to help where I can. I find this topic to be very interesting, since it first sparked my involvement with Wikipedia. CLewisZaereth (talk) 22:20, 17 March 2009 (UTC)


 * There is still one thing you need to think in (copied from WP:NOTTEXTBOOK): "Wikipedia is an encyclopedic reference, not a textbook. The purpose of Wikipedia is to present facts, not to teach subject matter. It is not appropriate to create or edit articles that read as textbooks, with leading questions and systematic problem solutions as examples. These belong on our sister projects Wikibooks and Wikisource. Other kinds of examples, specifically those intended to inform rather than to instruct, may be appropriate for inclusion in a Wikipedia article." - If you do not consider this, an editor might place the textbook template on the top of the article. Good luck... --Afluegel (talk) 22:25, 17 March 2009 (UTC)