Talk:Water: Difference between revisions
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:: I don't know either, that is why I put it here and not in the article. Maybe when somebody extends the article this small piece of information can be entered into it.--[[User:Paul Wormer|Paul Wormer]] 11:18, 31 August 2007 (CDT) | :: I don't know either, that is why I put it here and not in the article. Maybe when somebody extends the article this small piece of information can be entered into it.--[[User:Paul Wormer|Paul Wormer]] 11:18, 31 August 2007 (CDT) | ||
:::OK, I guess I forgot to mention, I can be stubborn sometimes when I think I'm right. I would like to give this one more try here. I think Milton has actually hit upon a possible solution for the complexity issues with "Physical properties", "Properties", "Other Properties", "element subpages"...I don't care what we call it! | |||
:::I say we need a system that's powerful enough to deal with Robert's question above, consistent from one article to the next, _and_ simple enough for reasonably inexperienced wiki authors to use.--[[User:David Yamakuchi|David Yamakuchi]] 07:53, 8 February 2010 (UTC) | |||
::Robert/Paul, how about something more like this: | |||
::http://en.citizendium.org/wiki/Water/Other_Properties | |||
:::Actually, it is spelled "celsius", not "celcius". And Daniel Mietchen recently created the article [[Celsius (unit)]] to which it should be linked in this manner: <nowiki> 0 [[Celsius (unit)|°C]]</nowiki> which would display as 0 [[Celsius (unit)|°C]]. Also why do we need to add that into http://en.citizendium.org/wiki/Water/Other_Properties when I already had put it into the table on the main article page in November 2009 ... long after Paul's comment in 2007? The whole idea of my Main Article table and of the blank table in the "Other properties" subpage that I added was to get away from using a template and just use the much simpler wiki table for additional properties. [[User:Milton Beychok|Milton Beychok]] 08:35, 8 February 2010 (UTC) | |||
::::We can spell it however you want. But you are apparently not understanding what Paul is saying above. '''Freezing point''' and '''Melting point''' are '''''NOT THE SAME THING'''''. You didn't include that information in any part of the article, and when I did you deleted. Is there a Constable in the house?--[[User:David Yamakuchi|David Yamakuchi]] 10:41, 8 February 2010 (UTC) | |||
::When we need to just enter simple info fast...no problem...IUPAC Name...CAS Number...not a lot of qualifications and discussion needed. Done. | |||
::When the data is more involved, maybe it needs a set of measurement conditions or qualifications specified or perhaps even a lengthy discussion about what theoretical methods were used to arrive at a particular numeric value, and the fact is that's pretty common with scientific "constants" like Freezing point of water...now we have a way to deal with it: | |||
::http://en.citizendium.org/wiki/Water/Freezing_Point::--[[User:David Yamakuchi|David Yamakuchi]] 07:53, 8 February 2010 (UTC) | |||
:::We don't need http://en.citizendium.org/wiki/Water/Freezing_Point at all. Any properties which are not already in the Main Article table of properties are meant to be added into the table in http://en.citizendium.org/wiki/Water/Other_Properties. [[User:Milton Beychok|Milton Beychok]] 08:35, 8 February 2010 (UTC) | |||
::::Got it! Message received. You don't need my help at all. I added the property to the /Other_Properties EXACTLY as you requested...and it's still no good. I'm trying to work with you here Milt...'''and''' address Paul Wormer's and Robert W King's questions...help me help you...--[[User:David Yamakuchi|David Yamakuchi]] 10:34, 8 February 2010 (UTC) | |||
== You got me! == | == You got me! == | ||
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Robert: Pardon my interloping and changing the approach to 'water'. You should feel free to undo and/or change it any way you see fit. Consider it only a suggestion. --[[User:Anthony.Sebastian|Anthony.Sebastian]] [[User talk:Anthony.Sebastian|(Talk)]] 23:05, 22 October 2007 (CDT) | Robert: Pardon my interloping and changing the approach to 'water'. You should feel free to undo and/or change it any way you see fit. Consider it only a suggestion. --[[User:Anthony.Sebastian|Anthony.Sebastian]] [[User talk:Anthony.Sebastian|(Talk)]] 23:05, 22 October 2007 (CDT) | ||
:I don't mind the changes at all as long as nothing factually was changed, although I did change the second title to "definition" as opposed to "other perspectives", because we have only the human perspective to work with. As far as any real objections, I defer to Dr Tito. --[[User:Robert W King|Robert W King]] 23:09, 22 October 2007 (CDT) | |||
:So far what I see is interesting, not just science but other ''interests'' as well. I wonder however if the topic of drought is brought up whtat will happen. The intention was to make it "multi-media"-like aka many different approaches. This seems to work. I do like to keep things in scientific line, no nonsense but stay to facts and adher to facts. By the way the name is Rob, if you like to keep it formal it's Dr. Tito. The one thing that's lacking and I haven't found a good example yet is a caged molecule in 3D by water as solvent as well as a visualization of the carbon (tetraeder) structure of water. These are sparse unfortunately. Anyone with a good link??? [[User:Robert Tito|Robert Tito]] | <span style="background:grey"> <font color="yellow"><b>[[User talk:Robert Tito|Talk]]</b></font> </span> | |||
== Rest energy == | |||
I'm puzzled by the following sentence: | |||
:''When cooled down to 0 K (absolute zero) or as close as can be practically achieved water is the only known substance (as of this date) that has a rest vibrational energy.'' | |||
Surely we don't talk about molecular vibrations here, this statement must relate to lattice vibrations. You are saying here that excited state lattice vibrations are populated at 0 K? This can only happen if there is some selection rule forbidding the transition to the ground state. Do you have a reference? --[[User:Paul Wormer|Paul Wormer]] 02:16, 23 October 2007 (CDT) | |||
== Common versus scientific usage == | |||
The introduction makes a very weird distinction between common and scientific use of water, as I as a scientist use water mainly in what is claimed to be the common use of that term. [[User:Kim van der Linde|Kim van der Linde]] 07:03, 23 October 2007 (CDT) | |||
==Scientific vs regular view== | |||
I actually think including two different views, one "layman" view and one "scientific" view is a decent way to present information--but it doesnt' change what water actually is. Does the reword help at all or does it still seem strange? Maybe a rewrite of that section would help? --[[User:Robert W King|Robert W King]] 22:38, 30 October 2007 (CDT) | |||
: I'm no longer sure which particular rewording you have in mind. However: Certainly different views should be there, but it should not be made to appear that the lay person and the scientist may be talking about two different things. [[User:Michael Hardy|Michael Hardy]] 21:40, 9 November 2007 (CST) | |||
== The biology perspective, quality, treatment... == | |||
In biology and health sciences, I'd say we can consider two basic kinds of water: hard water and soft water. Pure water (=H2O) is an abstraction: we encounter different degrees of water hardness, but, for living things, water is a vector not only of microbes, but of minerals. (DEF: the more minerals, the harder the water) | |||
The World Health Organization has been concerned by the treatment of waters, which removes everything but H2O. I quote: | |||
: ''The group concluded that there is sufficient epidemiological evidence of an inverse relationship between calcium and magnesium concentrations in drinking water and ischemic heart disease mortality, and that consumption of water containing calcium and magnesium, and therefore also the reintroduction of Mg and Ca into demineralized water in the remineralization process would likely provide health benefits in those consumer populations. There are no known harmful human health effects associated with the addition of calcium and magnesium within a large range and the nutritional benefits are...'' | |||
This should be connected (in particular, but not only) to the end of the CZ article: | |||
: ''In recent decades a market for "bottled water" has developed. This water is often advertised to have been additionally filtered, or to have come from a spring in order to enhance its "purity". The benefit of this bottled water has been disputed for a long time.'' [http://www.who.int/entity/water_sanitation_health/dwq/nutrconsensusrep.pdf Nutrient minerals in drinking-water and the potential health consequences of consumption of demineralized and remineralized and altered mineral content drinking-water: Consensus of the meeting] (or cf [http://www.who.int/water_sanitation_health/dwq/nutconsensus/en/ WHO expert group page]) | |||
This "dispute", can be characterized as a non-debate between | |||
1) The pure water market who advertises an abstract notion of purity | |||
and the | |||
2) Scientists who recognize that minerals are essential parts of what we call water. | |||
I would suggest to use the term "vector": | |||
Something like: "in biology / in living things, water is not only (H2O), but also a vector for various molecules / minerals and microorganisms." | |||
[[User:Pierre-Alain Gouanvic|Pierre-Alain Gouanvic]] 01:40, 14 January 2008 (CST) | |||
== Image == | |||
I have a request out there for a professional photo to be released under a CC license. [[User:Stephen Ewen|Stephen Ewen]] 02:11, 14 January 2008 (CST) | |||
:Got it. [[Image:Crystal ksmiletris.png|18px]] [[User:Stephen Ewen|Stephen Ewen]] 21:04, 21 January 2008 (CST) | |||
== The subsection entitled "The anomalies of water" == | |||
The subsection entitled "The anomalies of water" was added on September 14, 2008 by [[User:Pierre-Alain Gouanvic|Pierre-Alain Gouanvic]] and is a list of 65 so-called anomalies of water. That list was copied from an online publication by Professor Martin Chaplin of the London South Bank University. With all due respect to [[User:Pierre-Alain Gouanvic|Pierre-Alain Gouanvic]] and to Professor Martin Chaplin, I see no purpose served by that 65 item long list being in this article. | |||
I also question many of the so-called anomalies quoted below. For example: | |||
*"Water has unusually high melting point." Unusually high compared to what? I don't agree it is unusual. | |||
*"Water has unusually high boiling point." Unusually high compared to what? I don't agree it is unusual. | |||
*"Water has unusually high critical point." Unusually high compared to what? I don't agree it is unusual. | |||
*"Water has a low coefficient of expansion (thermal expansivity)." Low compared to what? Why is that an anomaly? | |||
*"The number of nearest neighbors increases on melting." What in the world does the "nearest neighbors" mean in this context? | |||
*"The number of nearest neighbors increases with temperature." What does in the world does the "nearest neighbors" mean in this context? | |||
*"The change in volume as liquid changes to gas is very large." That is '''not''' an anomaly. The change in volume is very large for all liquids as they change from their liquid phase to their gas phase. | |||
*"The specific heat capacity (CP and CV) is unusually high." Unusually high compared to what? I don't agree it is unusual. | |||
*Water has unusually high viscosity." Unusually high compared to what? I don't agree it is unusual. | |||
I could list others as well, but the above is sufficient to make my point that many of the so-called anomalies can be contested. Just finding statements in an article by a university professor and copying them does not necessarily mean that they are valid statements. | |||
But even without questioning the validity of the so-called anomalies, must the subject subsection list all 65 of them? Surely the subsection could just say in one sentence that Professor Chaplin, in his publication XXXX, lists 65 items that he believes are anomalies. Would anyone object if I (as a chemistry author) did that? [[User:Milton Beychok|Milton Beychok]] 07:01, 13 March 2009 (UTC) | |||
:Chris Day just answered my question by doing what I proposed be done. [[User:Milton Beychok|Milton Beychok]] 07:31, 13 March 2009 (UTC) | |||
== Added table of properties and re-arranged other images to minimize white space == | |||
I added a table of water properties into the lead-in introductory section. Then I re-sized and re-located other images so as to minimize the amount of white space in the text. | |||
Having the table of properties in the introductory section of the main article page means that the <nowiki>{{props}}</nowiki> template in the Properties subpage is redundant and should be deleted. But I don't know how to delete that template ... perhaps someone else could please do that. | |||
I suggest that the Properties subpage remain and be used only for adding supplementary properties that others may feel are needed. In that case, I suggest that the wording of the Properties subpage tab be changed to "More Properties". | |||
Including properties in the introductory section as well as having a "More Properties" subpage is essentially the same arrangement as is used in the Approved article [[Phosphorus]]. | |||
Any comments? [[User:Milton Beychok|Milton Beychok]] 03:09, 14 March 2009 (UTC) | |||
:I used a table format for the properties in the lead-in section so that changes or revisions in the property data can easily be made by anyone if needed. [[User:Milton Beychok|Milton Beychok]] 03:15, 14 March 2009 (UTC) | |||
=== About the border around the table in [[Water]] === | |||
(Originally posted to David Yamakuchi's talk page) | |||
Hi, David: Is there any way for you to center the table within the border that you created? I think it would look better if it were centered. [[User:Milton Beychok|Milton Beychok]] 15:47, 13 May 2009 (UTC) | |||
:It would seem the best way to get it centered is to view it in Firefox instead of IE :-) I spent about 1/2 hour yesterday before I saved the changes to get it to center correctly on my screen... Apparently there are still some rendering inconsistencies between the various browsers. Who knows what the right way to deal with this issue is, I'm not sure. The first couple of things I tried today didn't work. I suppose I can start by copying this over to the talk page. It seems to me that either Chris Day or Robert King (or both) had managed to solve this one before. FYI: Firefox seems to handle the right-side justification a little more smoothly also...um, just mentioning ;^)--[[User:David Yamakuchi|David Yamakuchi]] 00:38, 14 May 2009 (UTC) | |||
::David, why do we need the border? Can you just remove the border but leave the spacing between the table and the text? Is there any way to do that? [[User:Milton Beychok|Milton Beychok]] 01:35, 14 May 2009 (UTC) | |||
== Publisher's Description of reference 1 == | |||
Reference 1 includes a glowing and lengthy "Publisher's Description" of a book published by the Island Press along with a hyperlink to their website. Does that really belong in the article? [[User:Milton Beychok|Milton Beychok]] 05:57, 25 March 2009 (UTC) | |||
:Milton, I abbreviated the annotation to a core of information about what the reader will find in the book. Annotation no longer "lengthy" or "glowing". [[User:Anthony.Sebastian|Anthony.Sebastian]] 02:55, 7 August 2009 (UTC) | |||
== For Milton... == | |||
Is this editing or dehydrating? [[User:Howard C. Berkowitz|Howard C. Berkowitz]] 07:12, 7 August 2009 (UTC) | |||
== Please lets have shorter sentences and more conventional use of commas, semi-colons and mdashes!! == | |||
*The first sentence contained 54 words, 4 commas and 2 semi-colons. I broke it into 3 sentences. | |||
*The second sentence had 57 words. I broke it into two sentences. I am sure it can be shortened even further. | |||
*The second paragraph was one terribly convoluted and lengthy sentence consisting of 4 lines, 3 mdashes and 65 words. I read it four times and I'm still not sure I understood it. I deleted the entire paragraph as being too complex and not really needed at all. All it needed to say was that "Water (H<sub>2</sub>O) is a chemical substance consisting of hydrogen and oxygen." There was no need to get into atoms, molecules, unit entities, binding, and the number of naturally chemically occurring elements. | |||
I am sure we can do better than that! Sentences need not contain 54 to 65 words and they need not be so complex. [[User:Milton Beychok|Milton Beychok]] 07:15, 7 August 2009 (UTC) | |||
:Milton, I challenge myself to build 'great' sentences, information-rich sentences that flow, coherently, avoiding as much as possible weak verbs, like is, are, was, were, and other declensions of the verb 'to be', sentences that grow cumulatively, doing justice to the richness of the concepts the sentences attempt to articulate. Often such sentences need help in achieving those goals. Respectfully, I do not find it helpful for an editor to dissect such sentences and lay out the parts in a repetitive weak-verbed sentence-style — a personal opinion, of course. The number of words in a sentence do not indict it, nor do the number and variety of punctuation marks, and neither can suffice to justify a claim of complexity, a concept inapplicable to sentences. You found something wrong with the sentences in paragraphs 1 and 2, but you did not identify it, at least not for me. Nevertheless, I appreciate the sincerity of your editorial efforts, however much I disagree with them. [[User:Anthony.Sebastian|Anthony.Sebastian]] 03:35, 9 August 2009 (UTC) | |||
::Anthony, I thought that I had explained in my earlier comments why I revised the first paragraph. My explanation was that the sentences were too long and I broke them into shorter sentences. That is what I said just above, is it not? | |||
::As for the second paragraph, it was one long sentence that was too difficult for me to understand. As I said in my earlier comments, it really wasn't needed. Please note that the composition and properties of water are thorougly covered in "The chemistry persective" which is Section 2 in the Table of Contents. I had no problem understanding Section 2. | |||
::Just exactly what is the distinction between "weak verbs" and "strong verbs"? If using "strong" verbs equates to justifying overly long sentences and sentences that turn into paragraphs, then I guess we do indeed disagree. How can you say that "complexity is a concept inapplicable to sentences"? Surely, there are sentences which are short, clear and easily understood ... and there are sentences which are lengthy, complex and difficult to understand. | |||
::By the way, believe it or not, I wasn't even aware that you were involved in writing those two paragraphs when I made my edits and commented upon them. [[User:Milton Beychok|Milton Beychok]] 04:42, 9 August 2009 (UTC) | |||
== Table of Properties == | |||
The Table of Properties in the [[Water]] article is a nice, reasonably sized table, which can be used for many kinds of [[chemical compound]]s in general, except that I would add: | |||
#molar [[enthalpy]] of formation from the elements | |||
#molar [[entropy]] of formation from the elements | |||
#triple point temperature and pressure<br /> | |||
for future compounds. Molar [[Gibbs free energy]] of formation can be calculated from the enthalpy, entropy, and reference temperature, and may be considered redundant information, similar to listing entropy being redundant for phase changes. Viscosity information may not be so readily available for all compounds and may be taken out for some compounds. I changed "Boiling point" to "Normal boiling point" in this table since the boiling point (temperature) of water and other compounds depends on the external pressure. In theory the melting point does too, but in most cases there is very little effect of pressure on melting point, so I did not bother to make that change for melting point. [[User:Henry A. Padleckas|Henry A. Padleckas]] 05:41, 2 December 2009 (UTC) | |||
:Henry, thanks for revising "boiling point" to "normal boiling point" although the table does spell out that the boiling point was at a pressure of 1 atm. As for adding additional properties, that can be done easily on the Edit page. You might want to contact Peter Schmitt who has worked up a template of the properties table for use with other articles. [[User:Milton Beychok|Milton Beychok]] 16:28, 2 December 2009 (UTC) | |||
== Other Properties == | |||
Milton, you might want to look again. Freezing point, as Paul Wormer began discussing above, is indeed not specified in the "Main Article's table of Properties" as you claim. It's not even in the main article at all. | |||
Be aware, according to Paul it seems melting point is somehow _not_ the same as Freezing point...ironic as that may seem to those of us who only had five semesters of college Chemistry. He actually cites references, which I have updated here: [http://www.iapws.org/relguide/Ice-Rev2009.pdf] | |||
I have to admit, some of the partial derivatives and uncertainty numbers they cite are a little beyond me in terms of being useful, but that's not really the issue here...is it? | |||
Please stop deleting my edits without proper discussion. Thank you.--[[User:David Yamakuchi|David Yamakuchi]] 10:19, 8 February 2010 (UTC) | |||
:The difference between the melting and freezing point of water is simple: the freezing point is not measurable, whereas the melting point is. Very pure water (and we only want to consider pure water in this context) does not freeze without help of a solid crystallization kernel; very cold (metastable) liquid water is obtained by cooling down pure water (I forgot the actual numbers but I have in mind that supercooled liquid water of −40 °C can exist). For some reason (which I don't know) "superheated" ice does not exist, so ice always melts at 0 °C, while the transition from liquid to solid water appears at some fairly random temperatures below zero.--[[User:Paul Wormer|Paul Wormer]] 14:23, 8 February 2010 (UTC) | |||
::The [[supercooling point]] of pure water is around -42 °C under standard conditions, but liquid water can exist even below that temperature, especially at surfaces and in non-pure solutions. --[[User:Daniel Mietchen|Daniel Mietchen]] 15:59, 8 February 2010 (UTC) | |||
:::David, I thought that my above comments were indeed discussion of my reasons for removing redundant info from the "Other Properties" subpage. Paul and Daniel's comments here have made clear why I included the melting point of water (rather than freezing point) in the article. If I was a bit abrupt in my comments, then please excuse me and accept my apology for upsetting you. | |||
:::I would point out that you have again added the CAS number, the common name and the IUPAC name to the table in the "Other Properties" subpage ... which is redundant since they are all in the table in the Main Article. Please explain why you did that. If you meant that as an example, that's fine ... but they should not be permanently left there because they are redundant, and that is why I removed them. | |||
:::Please don't be in such a rush to call for a Constable. This article is in the Physics, Chemistry and Biology Workgroups and we have 3 Editors involved now ... Paul is a Chemistry and Physics Editor, Daniel is a Biology Editor and I am a Chemistry Editor. I think we can settle this amicably without a Constable, don't you? [[User:Milton Beychok|Milton Beychok]] 17:37, 8 February 2010 (UTC) | |||
::::Milton, we seem to have no shortage of editors here, I'll give you that. The fact is I didn't add the CAS, etc. in the first place...you did. Here: http://en.citizendium.org/wiki?title=Water/Other_Properties&oldid=100468037 | |||
::::Explain why I added it back in...I simply undid your last edit (deletion). Here: http://en.citizendium.org/wiki?title=Water/Other_Properties&oldid=100634395 I added the info, and you removed it because you didn't like it. This is not the first time either, you did the same in the [[Lead]] article too. That's why I called for a Constable.--[[User:David Yamakuchi|David Yamakuchi]] 20:17, 8 February 2010 (UTC) | |||
All: If Daniel and Paul's info on supercooling water is subsequently included in the article I have no problem with you removing the "subpage" that offends. That's how we can get out of this particular instance of subpages dilemma. I don't care if it goes in a table, text, picture, template, hell: write it in a song and sing it if you like. What I don't think we should do is remove it from the article without replacing it at all. You're going to strangle creativity here at CZ like that, and it's especially frustrating for us authors when an editor does it. | |||
I sought the appropriate feedback at the time I was helping to develop this particular technique here: http://en.citizendium.org/wiki/User_talk:David_Yamakuchi#Summary_of_what_you.27re_doing and here: http://en.citizendium.org/wiki/User_talk:Larry_Sanger/Archive_11#Summary_of_what_I.27m_doing | |||
The technique _does_ seem to work. What possible reasons would we have to want to delete something that's working without replacing it with something better?--[[User:David Yamakuchi|David Yamakuchi]] 20:17, 8 February 2010 (UTC) | |||
:David, just to clear the air a bit (I hope), I am not offended by the subpage and I do not wish to remove it. It is not a dilemma to me. It serves the function of a place to add additional property data. So, in the Properties table of the main article, I will add "Freezing point" and "Not measurable", which are the exact words used by Paul. Then I will remove "Freezing point" and "0 [[Ceslsius (unit)|C]]* " from the "Other Properties" subpage. [[User:Milton Beychok|Milton Beychok]] 21:15, 8 February 2010 (UTC) | |||
::To further clear the air, I don't understand your comment of "...you did the same in the [[Lead]] article too". I never made any edits to the properties info box in the [[Lead]] article. What I did there was to recommend on the Talk page that the section on Tetra-ethyl lead be removed and converted to a stand-alone article. Then '''after''' my recommendation was approved by Chris Day, Joe Quick and Ro Thorpe, I removed that section and subsequently created the stand-alone article with a properties table devoted to Tetra-ethyl lead. Why does that offend you? [[User:Milton Beychok|Milton Beychok]] 04:20, 9 February 2010 (UTC) | |||
==I thought we wanted the Freezing point value to read "Non measurable" or "Not measurable"== | |||
David, why does the freezing point value in the main article table of properties now read " 0 °C* "? I thought we wanted it to read "Non measurable" or "Not measurable" in response to the above comments by Paul Wormer and Daniel Mietchen? Somehow, the transclusion from your subpage has changed the freezing point of water to " 0 °C* " ... what gives? [[User:Milton Beychok|Milton Beychok]] 05:42, 11 February 2010 (UTC) | |||
::Chris Day has now reverted it back to "Not measurable". So all is now well (if it just stays that way). [[User:Milton Beychok|Milton Beychok]] 06:16, 11 February 2010 (UTC) | |||
::: Something strange happened here. I only corrected some typos (Celcius). The page looked ok and normal to me. Now there is [http://en.citizendium.org/wiki?title=Water/Freezing_point&oldid=100634965 this] revision (with talk page entries) before mine. --[[User:Peter Schmitt|Peter Schmitt]] 12:45, 11 February 2010 (UTC) | |||
::::Strictly speaking, the freezing point for any given sample of water or aqueous solution can be measured using a variety of methods (e.g. [[infrared thermography]] or [[NMR spectroscopy]]) but the point is that the process is [[stochastic]], such that the measured value varies from measurement to measurement, even within the same system. So I would suggest replacing "not measurable" by "variable" or "stochastic", perhaps with a qualifier of the sort "between 0°C and -42°C". | |||
::::I have quite a bit of literature (and actually some data) on the topic. For example, p. 17 of [http://dbm.neuro.uni-jena.de/pdf-daniel/Mietchen_2006_single-cell_MRI_fossils_cryo_PhD.pdf my thesis] states | |||
::::<blockquote>Water, like many liquids, can be supercooled below its melting point, and ice crystals only form around so-called nuclei whose molecular structure is closed to that of ice. In the absence of such nuclei, water remains liquid until the reduced thermal energy upon cooling restricts the motion of water molecules that much that they aggregate even closer and eventually form clusters that act as a nucleus and initiate crystallisation. The number of molecules required for such a nucleus composed entirely of water molecules decreases strongly with temperature and is about 4.5·10^4 at -5°C and about 70 at -40°C. At around -42°C (under atmospheric pressure), only two molecules are sufficient to initiate nucleation, and the liquid phase can not persist any further.</blockquote> | |||
::::Page 100:<blockquote>Freezing speed of distilled water has previously been reported to vary by as much as 5 orders of magnitude (Tabazadeh et al., 2002) under identical conditions. Thermoimaging experiments with identical solutions under identical conditions also point into the same direction (cf. Fig. 5.5B), and so it has to be kept in mind that all the MR experiments – at least those without living tissue which might somehow control nucleation – were affected by mechanisms causing similar scatter.</blockquote> | |||
::::I also have several GB of video data from such freezing processes as in Fig. 5.5B (p. 93) and should be able (time permitting) to turn one such sequence into an animation to be embedded into [[freezing point]] if any of you are up to start such an article. | |||
::::--[[User:Daniel Mietchen|Daniel Mietchen]] 13:04, 11 February 2010 (UTC) | |||
:::::For an overview on the matter: [[CZ:Ref:Koop 2009 Parameterizations for ice nucleation in biological and atmospheric systems]]. | |||
:::::--[[User:Daniel Mietchen|Daniel Mietchen]] 13:15, 11 February 2010 (UTC) | |||
[unindent] | |||
It is interesting that it so happens that Daniel is an expert on the freezing of water. I'm glad that the things I wrote off the top of my head (I'm away from home) are not too far off the mark.--[[User:Paul Wormer|Paul Wormer]] 14:31, 11 February 2010 (UTC) | |||
== Why last edit by Eduzendium student Jayvin Arora was removed. == | |||
This is the edit in question: <font color=green> One of the key properties that water exhibits is the hydrophilic effect. This is where a polar molecule that is able to for Hydrogen bonds forms them water, allowing the molecule to dissolve in water.</font> It was deleted because: | |||
*The second sentence does not make sense. Some of the words are either missing or mis-spelled or something. | |||
*The first sentence is grammatically okay but there is nothing unique about being hydrophilic ... many chemical compounds are hydrophilic. | |||
*The edit is followed by reference 5 but that reference (when searched) does not mention anything about being hydrophilic. The reference 5 evidently applies only to the sentence preceding this edit. | |||
[[User:Milton Beychok|Milton Beychok]] 21:52, 28 July 2010 (UTC) |
Latest revision as of 16:57, 7 March 2024
Wip
--Robert W King 12:23, 22 August 2007 (CDT)
Possible References:
- http://earthobservatory.nasa.gov/Study/WeighingWater/
- http://www.lsbu.ac.uk/water/molecule.html
- http://ga.water.usgs.gov/edu/characteristics.html
Elements
There are four "elements" of the earth--water, fire, wind, and earth itself; I have tried to alleviate any potential confusion by adding "non-chemical" element, and I hope it suits. --Robert W King 12:36, 23 August 2007 (CDT)
- "Non-chemical" does not make sense. See my edit summary. Michael Hardy 17:16, 24 August 2007 (CDT)
Definition of water
On the question of the definition of water: interestingly, in the philosophy of language, it is often discussed as an example what the meaning of "water" is (particularly, whether H20 is the "definition" of water--Putnam asked, if you came across something on "Twin Earth" that had the same observable properties as water, but was not H20, would that be water?). This is perhaps irrelevant, except in this general point: to speak of the definition of words for what philosophers call "natural kinds" (like water) is highly problematic. This does not mean that the words cannot be given definitions (obviously, they can), but rather that the criteria one might use to decide what is an "objective definition," so to speak, are not at all clear. And then of course most philosophers, following Wittgenstein and Quine, would in fact deny that words for natural kinds could be given definitions at all.
I suspect that asserting that water "by definition" is or is not liquid belies any understanding of these issues. Many people do mean something liquid when they speak of water, but maybe that's just because that's how water usually is when we encounter it. Anyway, if water were a liquid "by definition," then it would be contradictory to speak of frozen water, or water in a gaseous state. Clearly, that is not (always) contradictory, because we do use those phrases with good sense. --Larry Sanger 20:18, 24 August 2007 (CDT)
Also...stylistically, this article badly needs work. The style is wordy and pretentious-sounding. We can do much better. --Larry Sanger 20:20, 24 August 2007 (CDT)
Freezing point
The freezing point of water is not well-defined. However the melting point of hexagonal Ih ice (the naturally abundant ice) is well defined, it is 273.152519 K = 0.002519 celcius at 101.325 kPa see [1]--Paul Wormer 08:02, 31 August 2007 (CDT)
- Paul--in what context should this information be added? I'm slightly mystified. --Robert W King 10:12, 31 August 2007 (CDT)
- I don't know either, that is why I put it here and not in the article. Maybe when somebody extends the article this small piece of information can be entered into it.--Paul Wormer 11:18, 31 August 2007 (CDT)
- OK, I guess I forgot to mention, I can be stubborn sometimes when I think I'm right. I would like to give this one more try here. I think Milton has actually hit upon a possible solution for the complexity issues with "Physical properties", "Properties", "Other Properties", "element subpages"...I don't care what we call it!
- I say we need a system that's powerful enough to deal with Robert's question above, consistent from one article to the next, _and_ simple enough for reasonably inexperienced wiki authors to use.--David Yamakuchi 07:53, 8 February 2010 (UTC)
- Robert/Paul, how about something more like this:
- Actually, it is spelled "celsius", not "celcius". And Daniel Mietchen recently created the article Celsius (unit) to which it should be linked in this manner: 0 [[Celsius (unit)|°C]] which would display as 0 °C. Also why do we need to add that into http://en.citizendium.org/wiki/Water/Other_Properties when I already had put it into the table on the main article page in November 2009 ... long after Paul's comment in 2007? The whole idea of my Main Article table and of the blank table in the "Other properties" subpage that I added was to get away from using a template and just use the much simpler wiki table for additional properties. Milton Beychok 08:35, 8 February 2010 (UTC)
- We can spell it however you want. But you are apparently not understanding what Paul is saying above. Freezing point and Melting point are NOT THE SAME THING. You didn't include that information in any part of the article, and when I did you deleted. Is there a Constable in the house?--David Yamakuchi 10:41, 8 February 2010 (UTC)
- When we need to just enter simple info fast...no problem...IUPAC Name...CAS Number...not a lot of qualifications and discussion needed. Done.
- When the data is more involved, maybe it needs a set of measurement conditions or qualifications specified or perhaps even a lengthy discussion about what theoretical methods were used to arrive at a particular numeric value, and the fact is that's pretty common with scientific "constants" like Freezing point of water...now we have a way to deal with it:
- http://en.citizendium.org/wiki/Water/Freezing_Point::--David Yamakuchi 07:53, 8 February 2010 (UTC)
- We don't need http://en.citizendium.org/wiki/Water/Freezing_Point at all. Any properties which are not already in the Main Article table of properties are meant to be added into the table in http://en.citizendium.org/wiki/Water/Other_Properties. Milton Beychok 08:35, 8 February 2010 (UTC)
- Got it! Message received. You don't need my help at all. I added the property to the /Other_Properties EXACTLY as you requested...and it's still no good. I'm trying to work with you here Milt...and address Paul Wormer's and Robert W King's questions...help me help you...--David Yamakuchi 10:34, 8 February 2010 (UTC)
You got me!
You got me, Eddie! I'm slack on filling out the subpages pages. --Robert W King 21:45, 22 October 2007 (CDT)
- That's what colleagues are for, eh? :-) --Eddie Ortiz Nieves 21:48, 22 October 2007 (CDT)
Interloper
Robert: Pardon my interloping and changing the approach to 'water'. You should feel free to undo and/or change it any way you see fit. Consider it only a suggestion. --Anthony.Sebastian (Talk) 23:05, 22 October 2007 (CDT)
- I don't mind the changes at all as long as nothing factually was changed, although I did change the second title to "definition" as opposed to "other perspectives", because we have only the human perspective to work with. As far as any real objections, I defer to Dr Tito. --Robert W King 23:09, 22 October 2007 (CDT)
- So far what I see is interesting, not just science but other interests as well. I wonder however if the topic of drought is brought up whtat will happen. The intention was to make it "multi-media"-like aka many different approaches. This seems to work. I do like to keep things in scientific line, no nonsense but stay to facts and adher to facts. By the way the name is Rob, if you like to keep it formal it's Dr. Tito. The one thing that's lacking and I haven't found a good example yet is a caged molecule in 3D by water as solvent as well as a visualization of the carbon (tetraeder) structure of water. These are sparse unfortunately. Anyone with a good link??? Robert Tito | Talk
Rest energy
I'm puzzled by the following sentence:
- When cooled down to 0 K (absolute zero) or as close as can be practically achieved water is the only known substance (as of this date) that has a rest vibrational energy.
Surely we don't talk about molecular vibrations here, this statement must relate to lattice vibrations. You are saying here that excited state lattice vibrations are populated at 0 K? This can only happen if there is some selection rule forbidding the transition to the ground state. Do you have a reference? --Paul Wormer 02:16, 23 October 2007 (CDT)
Common versus scientific usage
The introduction makes a very weird distinction between common and scientific use of water, as I as a scientist use water mainly in what is claimed to be the common use of that term. Kim van der Linde 07:03, 23 October 2007 (CDT)
Scientific vs regular view
I actually think including two different views, one "layman" view and one "scientific" view is a decent way to present information--but it doesnt' change what water actually is. Does the reword help at all or does it still seem strange? Maybe a rewrite of that section would help? --Robert W King 22:38, 30 October 2007 (CDT)
- I'm no longer sure which particular rewording you have in mind. However: Certainly different views should be there, but it should not be made to appear that the lay person and the scientist may be talking about two different things. Michael Hardy 21:40, 9 November 2007 (CST)
The biology perspective, quality, treatment...
In biology and health sciences, I'd say we can consider two basic kinds of water: hard water and soft water. Pure water (=H2O) is an abstraction: we encounter different degrees of water hardness, but, for living things, water is a vector not only of microbes, but of minerals. (DEF: the more minerals, the harder the water)
The World Health Organization has been concerned by the treatment of waters, which removes everything but H2O. I quote:
- The group concluded that there is sufficient epidemiological evidence of an inverse relationship between calcium and magnesium concentrations in drinking water and ischemic heart disease mortality, and that consumption of water containing calcium and magnesium, and therefore also the reintroduction of Mg and Ca into demineralized water in the remineralization process would likely provide health benefits in those consumer populations. There are no known harmful human health effects associated with the addition of calcium and magnesium within a large range and the nutritional benefits are...
This should be connected (in particular, but not only) to the end of the CZ article:
- In recent decades a market for "bottled water" has developed. This water is often advertised to have been additionally filtered, or to have come from a spring in order to enhance its "purity". The benefit of this bottled water has been disputed for a long time. Nutrient minerals in drinking-water and the potential health consequences of consumption of demineralized and remineralized and altered mineral content drinking-water: Consensus of the meeting (or cf WHO expert group page)
This "dispute", can be characterized as a non-debate between
1) The pure water market who advertises an abstract notion of purity
and the
2) Scientists who recognize that minerals are essential parts of what we call water.
I would suggest to use the term "vector": Something like: "in biology / in living things, water is not only (H2O), but also a vector for various molecules / minerals and microorganisms."
Pierre-Alain Gouanvic 01:40, 14 January 2008 (CST)
Image
I have a request out there for a professional photo to be released under a CC license. Stephen Ewen 02:11, 14 January 2008 (CST)
- Got it. Stephen Ewen 21:04, 21 January 2008 (CST)
The subsection entitled "The anomalies of water"
The subsection entitled "The anomalies of water" was added on September 14, 2008 by Pierre-Alain Gouanvic and is a list of 65 so-called anomalies of water. That list was copied from an online publication by Professor Martin Chaplin of the London South Bank University. With all due respect to Pierre-Alain Gouanvic and to Professor Martin Chaplin, I see no purpose served by that 65 item long list being in this article.
I also question many of the so-called anomalies quoted below. For example:
- "Water has unusually high melting point." Unusually high compared to what? I don't agree it is unusual.
- "Water has unusually high boiling point." Unusually high compared to what? I don't agree it is unusual.
- "Water has unusually high critical point." Unusually high compared to what? I don't agree it is unusual.
- "Water has a low coefficient of expansion (thermal expansivity)." Low compared to what? Why is that an anomaly?
- "The number of nearest neighbors increases on melting." What in the world does the "nearest neighbors" mean in this context?
- "The number of nearest neighbors increases with temperature." What does in the world does the "nearest neighbors" mean in this context?
- "The change in volume as liquid changes to gas is very large." That is not an anomaly. The change in volume is very large for all liquids as they change from their liquid phase to their gas phase.
- "The specific heat capacity (CP and CV) is unusually high." Unusually high compared to what? I don't agree it is unusual.
- Water has unusually high viscosity." Unusually high compared to what? I don't agree it is unusual.
I could list others as well, but the above is sufficient to make my point that many of the so-called anomalies can be contested. Just finding statements in an article by a university professor and copying them does not necessarily mean that they are valid statements.
But even without questioning the validity of the so-called anomalies, must the subject subsection list all 65 of them? Surely the subsection could just say in one sentence that Professor Chaplin, in his publication XXXX, lists 65 items that he believes are anomalies. Would anyone object if I (as a chemistry author) did that? Milton Beychok 07:01, 13 March 2009 (UTC)
- Chris Day just answered my question by doing what I proposed be done. Milton Beychok 07:31, 13 March 2009 (UTC)
Added table of properties and re-arranged other images to minimize white space
I added a table of water properties into the lead-in introductory section. Then I re-sized and re-located other images so as to minimize the amount of white space in the text.
Having the table of properties in the introductory section of the main article page means that the {{props}} template in the Properties subpage is redundant and should be deleted. But I don't know how to delete that template ... perhaps someone else could please do that.
I suggest that the Properties subpage remain and be used only for adding supplementary properties that others may feel are needed. In that case, I suggest that the wording of the Properties subpage tab be changed to "More Properties".
Including properties in the introductory section as well as having a "More Properties" subpage is essentially the same arrangement as is used in the Approved article Phosphorus.
Any comments? Milton Beychok 03:09, 14 March 2009 (UTC)
- I used a table format for the properties in the lead-in section so that changes or revisions in the property data can easily be made by anyone if needed. Milton Beychok 03:15, 14 March 2009 (UTC)
About the border around the table in Water
(Originally posted to David Yamakuchi's talk page)
Hi, David: Is there any way for you to center the table within the border that you created? I think it would look better if it were centered. Milton Beychok 15:47, 13 May 2009 (UTC)
- It would seem the best way to get it centered is to view it in Firefox instead of IE :-) I spent about 1/2 hour yesterday before I saved the changes to get it to center correctly on my screen... Apparently there are still some rendering inconsistencies between the various browsers. Who knows what the right way to deal with this issue is, I'm not sure. The first couple of things I tried today didn't work. I suppose I can start by copying this over to the talk page. It seems to me that either Chris Day or Robert King (or both) had managed to solve this one before. FYI: Firefox seems to handle the right-side justification a little more smoothly also...um, just mentioning ;^)--David Yamakuchi 00:38, 14 May 2009 (UTC)
- David, why do we need the border? Can you just remove the border but leave the spacing between the table and the text? Is there any way to do that? Milton Beychok 01:35, 14 May 2009 (UTC)
Publisher's Description of reference 1
Reference 1 includes a glowing and lengthy "Publisher's Description" of a book published by the Island Press along with a hyperlink to their website. Does that really belong in the article? Milton Beychok 05:57, 25 March 2009 (UTC)
- Milton, I abbreviated the annotation to a core of information about what the reader will find in the book. Annotation no longer "lengthy" or "glowing". Anthony.Sebastian 02:55, 7 August 2009 (UTC)
For Milton...
Is this editing or dehydrating? Howard C. Berkowitz 07:12, 7 August 2009 (UTC)
Please lets have shorter sentences and more conventional use of commas, semi-colons and mdashes!!
- The first sentence contained 54 words, 4 commas and 2 semi-colons. I broke it into 3 sentences.
- The second sentence had 57 words. I broke it into two sentences. I am sure it can be shortened even further.
- The second paragraph was one terribly convoluted and lengthy sentence consisting of 4 lines, 3 mdashes and 65 words. I read it four times and I'm still not sure I understood it. I deleted the entire paragraph as being too complex and not really needed at all. All it needed to say was that "Water (H2O) is a chemical substance consisting of hydrogen and oxygen." There was no need to get into atoms, molecules, unit entities, binding, and the number of naturally chemically occurring elements.
I am sure we can do better than that! Sentences need not contain 54 to 65 words and they need not be so complex. Milton Beychok 07:15, 7 August 2009 (UTC)
- Milton, I challenge myself to build 'great' sentences, information-rich sentences that flow, coherently, avoiding as much as possible weak verbs, like is, are, was, were, and other declensions of the verb 'to be', sentences that grow cumulatively, doing justice to the richness of the concepts the sentences attempt to articulate. Often such sentences need help in achieving those goals. Respectfully, I do not find it helpful for an editor to dissect such sentences and lay out the parts in a repetitive weak-verbed sentence-style — a personal opinion, of course. The number of words in a sentence do not indict it, nor do the number and variety of punctuation marks, and neither can suffice to justify a claim of complexity, a concept inapplicable to sentences. You found something wrong with the sentences in paragraphs 1 and 2, but you did not identify it, at least not for me. Nevertheless, I appreciate the sincerity of your editorial efforts, however much I disagree with them. Anthony.Sebastian 03:35, 9 August 2009 (UTC)
- Anthony, I thought that I had explained in my earlier comments why I revised the first paragraph. My explanation was that the sentences were too long and I broke them into shorter sentences. That is what I said just above, is it not?
- As for the second paragraph, it was one long sentence that was too difficult for me to understand. As I said in my earlier comments, it really wasn't needed. Please note that the composition and properties of water are thorougly covered in "The chemistry persective" which is Section 2 in the Table of Contents. I had no problem understanding Section 2.
- Just exactly what is the distinction between "weak verbs" and "strong verbs"? If using "strong" verbs equates to justifying overly long sentences and sentences that turn into paragraphs, then I guess we do indeed disagree. How can you say that "complexity is a concept inapplicable to sentences"? Surely, there are sentences which are short, clear and easily understood ... and there are sentences which are lengthy, complex and difficult to understand.
- By the way, believe it or not, I wasn't even aware that you were involved in writing those two paragraphs when I made my edits and commented upon them. Milton Beychok 04:42, 9 August 2009 (UTC)
Table of Properties
The Table of Properties in the Water article is a nice, reasonably sized table, which can be used for many kinds of chemical compounds in general, except that I would add:
- molar enthalpy of formation from the elements
- molar entropy of formation from the elements
- triple point temperature and pressure
for future compounds. Molar Gibbs free energy of formation can be calculated from the enthalpy, entropy, and reference temperature, and may be considered redundant information, similar to listing entropy being redundant for phase changes. Viscosity information may not be so readily available for all compounds and may be taken out for some compounds. I changed "Boiling point" to "Normal boiling point" in this table since the boiling point (temperature) of water and other compounds depends on the external pressure. In theory the melting point does too, but in most cases there is very little effect of pressure on melting point, so I did not bother to make that change for melting point. Henry A. Padleckas 05:41, 2 December 2009 (UTC)
- Henry, thanks for revising "boiling point" to "normal boiling point" although the table does spell out that the boiling point was at a pressure of 1 atm. As for adding additional properties, that can be done easily on the Edit page. You might want to contact Peter Schmitt who has worked up a template of the properties table for use with other articles. Milton Beychok 16:28, 2 December 2009 (UTC)
Other Properties
Milton, you might want to look again. Freezing point, as Paul Wormer began discussing above, is indeed not specified in the "Main Article's table of Properties" as you claim. It's not even in the main article at all.
Be aware, according to Paul it seems melting point is somehow _not_ the same as Freezing point...ironic as that may seem to those of us who only had five semesters of college Chemistry. He actually cites references, which I have updated here: [2]
I have to admit, some of the partial derivatives and uncertainty numbers they cite are a little beyond me in terms of being useful, but that's not really the issue here...is it?
Please stop deleting my edits without proper discussion. Thank you.--David Yamakuchi 10:19, 8 February 2010 (UTC)
- The difference between the melting and freezing point of water is simple: the freezing point is not measurable, whereas the melting point is. Very pure water (and we only want to consider pure water in this context) does not freeze without help of a solid crystallization kernel; very cold (metastable) liquid water is obtained by cooling down pure water (I forgot the actual numbers but I have in mind that supercooled liquid water of −40 °C can exist). For some reason (which I don't know) "superheated" ice does not exist, so ice always melts at 0 °C, while the transition from liquid to solid water appears at some fairly random temperatures below zero.--Paul Wormer 14:23, 8 February 2010 (UTC)
- The supercooling point of pure water is around -42 °C under standard conditions, but liquid water can exist even below that temperature, especially at surfaces and in non-pure solutions. --Daniel Mietchen 15:59, 8 February 2010 (UTC)
- David, I thought that my above comments were indeed discussion of my reasons for removing redundant info from the "Other Properties" subpage. Paul and Daniel's comments here have made clear why I included the melting point of water (rather than freezing point) in the article. If I was a bit abrupt in my comments, then please excuse me and accept my apology for upsetting you.
- I would point out that you have again added the CAS number, the common name and the IUPAC name to the table in the "Other Properties" subpage ... which is redundant since they are all in the table in the Main Article. Please explain why you did that. If you meant that as an example, that's fine ... but they should not be permanently left there because they are redundant, and that is why I removed them.
- Please don't be in such a rush to call for a Constable. This article is in the Physics, Chemistry and Biology Workgroups and we have 3 Editors involved now ... Paul is a Chemistry and Physics Editor, Daniel is a Biology Editor and I am a Chemistry Editor. I think we can settle this amicably without a Constable, don't you? Milton Beychok 17:37, 8 February 2010 (UTC)
- Milton, we seem to have no shortage of editors here, I'll give you that. The fact is I didn't add the CAS, etc. in the first place...you did. Here: http://en.citizendium.org/wiki?title=Water/Other_Properties&oldid=100468037
- Explain why I added it back in...I simply undid your last edit (deletion). Here: http://en.citizendium.org/wiki?title=Water/Other_Properties&oldid=100634395 I added the info, and you removed it because you didn't like it. This is not the first time either, you did the same in the Lead article too. That's why I called for a Constable.--David Yamakuchi 20:17, 8 February 2010 (UTC)
All: If Daniel and Paul's info on supercooling water is subsequently included in the article I have no problem with you removing the "subpage" that offends. That's how we can get out of this particular instance of subpages dilemma. I don't care if it goes in a table, text, picture, template, hell: write it in a song and sing it if you like. What I don't think we should do is remove it from the article without replacing it at all. You're going to strangle creativity here at CZ like that, and it's especially frustrating for us authors when an editor does it.
I sought the appropriate feedback at the time I was helping to develop this particular technique here: http://en.citizendium.org/wiki/User_talk:David_Yamakuchi#Summary_of_what_you.27re_doing and here: http://en.citizendium.org/wiki/User_talk:Larry_Sanger/Archive_11#Summary_of_what_I.27m_doing
The technique _does_ seem to work. What possible reasons would we have to want to delete something that's working without replacing it with something better?--David Yamakuchi 20:17, 8 February 2010 (UTC)
- David, just to clear the air a bit (I hope), I am not offended by the subpage and I do not wish to remove it. It is not a dilemma to me. It serves the function of a place to add additional property data. So, in the Properties table of the main article, I will add "Freezing point" and "Not measurable", which are the exact words used by Paul. Then I will remove "Freezing point" and "0 C* " from the "Other Properties" subpage. Milton Beychok 21:15, 8 February 2010 (UTC)
- To further clear the air, I don't understand your comment of "...you did the same in the Lead article too". I never made any edits to the properties info box in the Lead article. What I did there was to recommend on the Talk page that the section on Tetra-ethyl lead be removed and converted to a stand-alone article. Then after my recommendation was approved by Chris Day, Joe Quick and Ro Thorpe, I removed that section and subsequently created the stand-alone article with a properties table devoted to Tetra-ethyl lead. Why does that offend you? Milton Beychok 04:20, 9 February 2010 (UTC)
I thought we wanted the Freezing point value to read "Non measurable" or "Not measurable"
David, why does the freezing point value in the main article table of properties now read " 0 °C* "? I thought we wanted it to read "Non measurable" or "Not measurable" in response to the above comments by Paul Wormer and Daniel Mietchen? Somehow, the transclusion from your subpage has changed the freezing point of water to " 0 °C* " ... what gives? Milton Beychok 05:42, 11 February 2010 (UTC)
- Chris Day has now reverted it back to "Not measurable". So all is now well (if it just stays that way). Milton Beychok 06:16, 11 February 2010 (UTC)
- Something strange happened here. I only corrected some typos (Celcius). The page looked ok and normal to me. Now there is this revision (with talk page entries) before mine. --Peter Schmitt 12:45, 11 February 2010 (UTC)
- Strictly speaking, the freezing point for any given sample of water or aqueous solution can be measured using a variety of methods (e.g. infrared thermography or NMR spectroscopy) but the point is that the process is stochastic, such that the measured value varies from measurement to measurement, even within the same system. So I would suggest replacing "not measurable" by "variable" or "stochastic", perhaps with a qualifier of the sort "between 0°C and -42°C".
- I have quite a bit of literature (and actually some data) on the topic. For example, p. 17 of my thesis states
Water, like many liquids, can be supercooled below its melting point, and ice crystals only form around so-called nuclei whose molecular structure is closed to that of ice. In the absence of such nuclei, water remains liquid until the reduced thermal energy upon cooling restricts the motion of water molecules that much that they aggregate even closer and eventually form clusters that act as a nucleus and initiate crystallisation. The number of molecules required for such a nucleus composed entirely of water molecules decreases strongly with temperature and is about 4.5·10^4 at -5°C and about 70 at -40°C. At around -42°C (under atmospheric pressure), only two molecules are sufficient to initiate nucleation, and the liquid phase can not persist any further.
- Page 100:
Freezing speed of distilled water has previously been reported to vary by as much as 5 orders of magnitude (Tabazadeh et al., 2002) under identical conditions. Thermoimaging experiments with identical solutions under identical conditions also point into the same direction (cf. Fig. 5.5B), and so it has to be kept in mind that all the MR experiments – at least those without living tissue which might somehow control nucleation – were affected by mechanisms causing similar scatter.
- I also have several GB of video data from such freezing processes as in Fig. 5.5B (p. 93) and should be able (time permitting) to turn one such sequence into an animation to be embedded into freezing point if any of you are up to start such an article.
- --Daniel Mietchen 13:04, 11 February 2010 (UTC)
- For an overview on the matter: CZ:Ref:Koop 2009 Parameterizations for ice nucleation in biological and atmospheric systems.
- --Daniel Mietchen 13:15, 11 February 2010 (UTC)
[unindent]
It is interesting that it so happens that Daniel is an expert on the freezing of water. I'm glad that the things I wrote off the top of my head (I'm away from home) are not too far off the mark.--Paul Wormer 14:31, 11 February 2010 (UTC)
Why last edit by Eduzendium student Jayvin Arora was removed.
This is the edit in question: One of the key properties that water exhibits is the hydrophilic effect. This is where a polar molecule that is able to for Hydrogen bonds forms them water, allowing the molecule to dissolve in water. It was deleted because:
- The second sentence does not make sense. Some of the words are either missing or mis-spelled or something.
- The first sentence is grammatically okay but there is nothing unique about being hydrophilic ... many chemical compounds are hydrophilic.
- The edit is followed by reference 5 but that reference (when searched) does not mention anything about being hydrophilic. The reference 5 evidently applies only to the sentence preceding this edit.
Milton Beychok 21:52, 28 July 2010 (UTC)
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