Talk:Water (molecule)

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[edit] Density

Mkay I am not that good at chemistry but isnt the density of water 998 g/cm^3, then how could it be 1000 kg/m^3? Should it not be 998 kg/m^3? Or am I missing something? 87.96.132.194 17:44, 11 October 2006 (UTC)

I believe that the density of water is dependent upon its temperature, but I'm not very familiar with this subject either. Hopefully someone else will come and explain better. Jecowa 21:44, 11 October 2006 (UTC)

Density is indeed temperature-dependent, and the article even has a table listing density of (liquid) water at various temperatures. DMacks 22:47, 11 October 2006 (UTC)

[edit] History section change

I moved the part on Celsius to be below the part about Farenheit. It was kind of illogical to have Celsius first because the order was by year and Celsius part happend(according to the text) after Farenheit. 87.96.132.194 17:50, 11 October 2006 (UTC)

[edit] Compressibility coefficient

The article doesn't acknowledge the fact that compressibility might depend on temperature, or that change in volume might not be a linear function of pressure. In fact, the quantity provided requires specification of the temperature and pressure at which it's meassured. The reference given does not help either. I don't have time to fix this now, I'll try to do it later, but if anybody beats me to it, I'd apreciate it.--Tariuk 21:51, 19 August 2006 (UTC)

[edit] A formula to calculate the freezing point of water

I need a formula to calculate the freezing point of water at arbitrary heights in the Earth's atmosphere, so far all I've found is this Freezing Point Calculator, but i need the equation itself, which granted i could get from the JavaScript there but that appears to be for seawater. -- Ævar Arnfjörð Bjarmason 02:53, 2004 Dec 14 (UTC) Are you by any chance talking about the point at which atmospheric moisture freezes? if so the A.S.H.R.A.E dew-point calculator is wahat you need. the freezing of water is quite straight forward e.g. for each 1 pound of water

                           A/ temperature difference from freezing x BTU degrees F.
                           B/ plus latent heat of fusion
                       (minus # of degrees F. x 1 b.t.u.)+ latent heat of fusion 
          This gives the total amount of heat required to A/reduce to freezing temperature 
                                                          B/effect the change of state

If I remember my trade-school science the latent heat of fusion is 451 btu per pound, these calculations are for 1 atmosphere of pressure and for practical purposes disregard the H in your formula! So the H in the formula is 500 or 1000 (metres or feet)

A little googling turned up this page from Ask A Scientist, which gives this:

$\frac{\Delta{P}}{\Delta{T}} = \frac{\Delta{H}}{T\Delta{V}}$

Do you say, by any chance have on that does not assume knowledge of physics? Like an example of how to calculate this for 500 and 1000 metres? -- Ævar Arnfjörð Bjarmason 13:05, 2004 Dec 15 (UTC)

If you're worried about salinity, you might also be interested in Raoult's law. --David Iberri | Talk 05:45, Dec 14, 2004 (UTC)

I couldn't find a straight-forward formula for this, but the Naval Pacific Meteorology and Oceanography Center [1] explains how to calculate the temperature using a Skew T, Log P Diagram (DOD WPC 9-16). You can probably order the DOD WPC 9-16 online. If you know how to code, there is code (from 1978!) located here that generates the DOD WPC 9-16. SWAdair | Talk 05:52, 14 Dec 2004 (UTC)

[edit] Amphoteric nature of water

I cleaned up some things in the section "Amphoteric nature of water", but there are two things I'm not entirely sure about.

The section starts out saying that water can act as an acid or base, then later says it can acta as an acid or alkali. I think it should be "base" everywhere. (See Alkali#Confusion between base and alkali).
It says "equilibrium" but the arrow points only to the right. My guess is that it should say "reaction", but perhaps it was meant as an equilibrium and the arrow should go both ways? If so, how about the reaction with NH3 below?

Fpahl 22:42, 21 Sep 2004 (UTC)

The symbols ↔ and → don't show up in Opera 7.23. Why not <==> instead? Vsmith 15:32, 24 Sep 2004 (UTC)

Hmm... they do on my XP at home, also using Opera 7.23. Using Win98 on school computer where I noted the problem. ??? Vsmith 00:45, 25 Sep 2004 (UTC)

Anyway - replaced alkali w/ base in this section and changed ammonia reaction to reversible also. Vsmith 00:45, 25 Sep 2004 (UTC)

I looked for something in the style manual on chemical formulas, but there doesn't seem to be anything. I looked at other pages with chemistry, and they almost invariably use these arrows. Chemical equilibrium has a nice TeXed formula, but it's not that much nicer, and it would be a lot of effort to change everything to that and keep it that way, apart from the fact that things then look different from the formulas within the text. I have no idea how many Opera users with Windows 98 there are -- do you think it's acceptable to leave it as it is? Win98 will soon be dying out anyway, I guess... "<-->" (not "<==>") would be OK, I guess, but I'd be reluctant to change to something "less advanced" because of a relatively limited problem that will go away over time. Fpahl 10:26, 25 Sep 2004 (UTC)

[edit] Anthropic principle? Eh? Come again.

<< Begin copy from Talk:Water since the Water (molecule) page split from the Water page >>

There have been several conflicting edits on fine-tuning and anthropic principle. I believe that all edits have a bit of truth, and that keeping only one explanation to the unusual property of life is NPOV. Shouldn't we have one short paragraph briefly explaining the various answers as explained in fine-tuned universe, with a link to fine-tuned universe for more details ? And move any further discussion to this article ?

It's not gonna be easy :) -- I personally see no reason for inclusion of anthropic principle or fine tuning for life as both imply a designer and are nonscientific and unfalsifiable. Evolution is about the fine tuning of life forms to their environment.--Vsmith 22:14, 23 Sep 2004 (UTC)

Wikipedia is an encyclopedy, not a scientific compendium. It contains many philosophical or religious articles. I do not see why such issues would have to be removed from a "water" article. Pcarbonn 06:47, 24 Sep 2004 (UTC)

<<End copy from the Talk:Water page >>

From the current Water (molecule) page:

<<This is one of the principal examples of finely-tuned physical properties that support life on Earth that is used as an argument for the anthropic principle.>>

This sentence about "finely-tuned" and "anthropic principle" does not make logical sense. Even if God in all her great generosity made the bottom of freshwater lakes 4 degrees warmer than the bottom of the Arctic Ocean, this would not be an example of an anthropic principle but rather a difference between fresh water and salt water. Furthermore, this difference between the bottom of salt water and the bottom of fresh water does not clearly benefit man because man as God made him does not live on the bottom of either fresh water or salt water. So I suggest this sentence should be either 1) deleted or 2) those interested in keeping this sentence in the water page should provide a reference that explains the connection between 1) the temperature at the bottom of a body of water and 2) the anthropic principle. ---Rednblu 10:58, 24 Sep 2004 (UTC)

Life started in the water, and it's at least plausible that it might be impossible for it to get off the ground on land, if you'll excuse the pun. So there would appear to be a case for a connection between the anomalous properties of water and the existence of life. IMO the only potential problem is POVness with respect to the philosopical status of the "fine-tuning" and the anthropic principle. It seems to me that the sentence does a good NPOV job by saying that this is "used as an argument", which is certainly a fact, but one might still object that "finely-tuned" is used without such a qualification, and it might be taken to imply a process of "tuning" or even a "tuner". IMO this is a sufficiently neutral word, though. Fpahl 11:38, 24 Sep 2004 (UTC)

---

I don't disagree with your "possibility" arguments. Many things are "possible."

But I doubt that any peer-reviewed article uses the properties of freshwater at 4 degrees as the basis to argue that there has been an anthropic principle at work. The totality of human evolution could have occurred in that region of the earth where water never freezes.
If you are referring to applications of Barrow & Tipler's book, then I suggest that you move the argument to a section of its own called maybe "Mainstream science versus the anthropic principle" wherein you would present both sides of the argument. Mainstream science makes the argument inverse of the anthropic principle; mainstream science argues that natural selection tunes every creature to take advantage of whatever the properties of water are in whatever environment the creature finds itself; furthermore, where natural selection does not tune the creature "fine-enough" to take advantage of the properties of water in the creature's environment, the creature dies; no anthropic principle is necessary to explain the facts; hence, Occam's razor slices every anthropic principle or any other variation of God and her handiwork from every valid hypothesis, given current facts.
Furthermore, if you are extending what Barrow & Tipler wrote, I do believe that you missed Barrow & Tipler's definition of anthropic principle.
It would greatly assist this enterprise if you would cite to a peer-reviewed article that uses the properties of freshwater at 4 degrees to argue for the operation of an anthropic principle. ---Rednblu 17:02, 24 Sep 2004 (UTC)

---

Moved fine tuning & anthropo references to new Philosophy and Religion section after History. Vsmith 15:55, 24 Sep 2004 (UTC)

---

Good idea; in the right direction; good clarification of the "argument." However, in my opinion, merely moving the unsupported, undocumented, and uncited nonsense sentence to "Philosophy and Religion" does not get rid of the deception in the sentence. That is, in my opinion, the anthropic principle does not manifest either legitimate philosophy or legitimate religion, but rather pseudoscience. Accordingly, I would suggest that the title of this section should be something like "Scientific method versus pseudoscience"; with that title the reader is properly alerted to the texture of the "argument." ---Rednblu 17:48, 24 Sep 2004 (UTC)

---

Could some one explain why "bottom of fresh water at 4 °C" is a pre-requisite for life as we know it ? The mainstream thinking on the origin of life is that it started at the bottom of the seas, where the argument does not hold. So life could have started without this special property of water. The expansion of life from the sea to the ground does not seem to critically depend on that property of water either (although it sure helps) Pcarbonn 20:46, 24 Sep 2004 (UTC)

Hear, hear! ---Rednblu 21:13, 24 Sep 2004 (UTC)

On the other hand, the fact that fatty substances create cells in water is critical for life and the process of evolution as we know it. However, any other solvent than water probably has the same property: insoluble substances will tend to create cells in them too, am I right ? So, life could theoretically evolve in any other solvent, I would think (although it has never been observed of course). Pcarbonn 20:46, 24 Sep 2004 (UTC)

Sounds right--as a possibility! ---Rednblu 21:13, 24 Sep 2004 (UTC)

We have three separate questions here.

Is the expansion of fresh water below 4 °C a pre-requisite for life as we know it? The article itself states that this applies only to fresh water, not to salt water. In that case, even if the oceans were significantly less salty when life got started, this would not be an argument for an anthropic principle, since life could otherwise have waited until the oceans were salty enough (unless they can become salty only through life processes, which I doubt). Thus, the specific argument about the expansion would be simply false, regardless of any philosophical subtleties. However, this otherwise seemingly credible page says that oceans also freeze from the top. Who's right?
Are there any "fine-tuned" properties of water? I don't know, but since the same page lists 41 anomalies of water, there might well be. Do the proponents of the fine-tuning argument mention any other than the anomalous thermal expansion?
Is the whole idea of the anthropic principle "pseudoscientific", as Rednblu claims, arguing that it's natural selection that does the fine-tuning? As far as I'm aware, "mainstream science" is a long way from being able to decide which laws of physics might allow for the possibility of life and which might not. It could be that for most other, even nearby values of the constants of nature, no life could exist. There would be nothing for natural selection to fine-tune. This is obviously an extremely difficult question to decide, but it could in principle be decided, so I disagree with the claim that Occam's razor would in principle do away with any anthropic principle. Fpahl 16:54, 8 Oct 2004 (UTC)

Re. #1 above. I've added a bit on freezing seawater to (hopefully) clarify this point. So ocean bottom water is maybe -2 deg C (depends on pressure - should look up data on deep ocean temps). However, water temperature around black smokers is a lot hotter and at least one abiogenesis theory says that's where the action was :-) -Vsmith 04:48, 9 Oct 2004 (UTC)

[edit] Water as a liquid crystal

Can someone write about Penta, a patented bottled water brand which uses ultrasound to reorganise the water molecules into pentacomplices, whose form is claimed to be more readily absorbed in the body than regular water? lysdexia 08:08, 17 Oct 2004 (UTC)

Never heard of it (but, there is much I haven't heard of:) - sounds like an advertising/marketing ploy to me. Removed attention banner - not what it is for. -Vsmith 15:25, 17 Oct 2004 (UTC)

OK - did some googling, got 99% marketing hype. Here's a link that gives some perspective from Randi the Debunker -Vsmith 15:58, 17 Oct 2004 (UTC)

I just put together a provisional Penta Water page. Let me know what you think. Let's see what their lawyers think! Christianjb 05:30, 15 Mar 2005 (UTC)

Sorry, but this is pure pseudoscience. Ed Sanville 01:28, 30 August 2005 (UTC)

[edit] Restructure

I restructured the article to avoid duplication of headings and combine material - hopefully for a better read. Much of the old Properties of water was duplicated in part under Physics and chemistry. Also deleted a bit that is covered better in the water article. Could probably do some more rewriting of combined topic materials, but there's always more. -Vsmith 04:34, 9 Nov 2004 (UTC)

That should make it much easier to follow than it was previously. Good work. WaterGuy

[edit] Electrical properties/Ultrapure

I fully appreciate the edits to correct my atroicous spelling :) and formatting to a recent edit I made but I do think one part should remain the same. The section in question was changed to:

"It is known that the theoretical maximum electrical resistivity for water is approximately 182 kilohm-meters at 25 degrees Celsius. This figure agrees well with what is typically seen on reverse osmosis, ultrafiltered and deionized ultrapure water systems used for instance, in semiconductor manufacturing plants. A salt or acid contaminant level exceeding that of even 100 parts per trillion (ppt) in ultrapure water will begin to noticably raise its conductivity level by up to several hundred kilosiemens per meter."

Now, I know wikipedia must conform to standards, a policy which I am an ardent advocate of, and the meter is the SI unit of length as is the kilohm. However, ultrapure water is never, ever referred to using these units. It is always referred to as being 18.2 megohm-cm and has in fact been so often used with these terms that it has bcome synonymous with them and is often simply called "megohm water" in the literature. So I'd like to change this back in the article......--Deglr6328 17:10, 16 Feb 2005 (UTC)

Added 18.2 megohm-cm after the kohm amount for clarity. Vsmith 17:46, 16 Feb 2005 (UTC)

I did a fairly detailed reply to Deglr6328's last comment in editing, and must have previewed and closed browser without saving it. The gist of it was that you are now on the right track, but more fine-tuning needs to be done. Don't have time to reconstruct it all right now, but will try to get back here later. Gene Nygaard 04:22, 18 Feb 2005 (UTC)

Shouldn't the conductance change be several hundred nanosiemens per meter, if the resistivity is lowered by several kiloohm-meters from 182 kiloohm-meter? R6144 14:07, 21 August 2005 (UTC)

Another Fox 15:31, 11 August 2006 (UTC) Can we have a consistancy between Mohm-cm and nanosiemens because at the moment its not particularly clear what the value is. ie with 100 ppt salt (de-ionised) the value becomes 1 Mohm-cm rather than some nanosiemens. Does anybody know the conducivity of tap water in Mohm-cm.

[edit] thermodynamic data

Why does this page(or any other chemical page) have no thermodynamic data in the information bar on the right hand side? There should be heats of formation, heats of combustion, specific heats, heat of fusion, and heat of vaporization listed at STP. I don't understand why this information would not be included but the viscosity is. Viscosity is not a common use in calculations unless you are a chemical engineer but various thermodynamic properties are very usefull.

Click on the "thermodynamic data" link and you will see what you need. This is true for all of the infoboxes- assuming these data have been uploaded. I have answered the question in a more detailed way here.Walkerma 17:29, 22 July 2005 (UTC)

[edit] Correct pKa and pKb for water

The correct pKa and pKb for water at room conditions (1 atm and 25^oC) are 15.74, NOT 7.00! Here's why:

It is commonly known that Kw is 1.0 * 10^-14. Now, remember that the expression for Kw is [H₃O⁺][OH^-]. In pure water, there are roughly 10^1.74 moles of water per liter, so [H₂O] = 10^1.74. The expression for Ka of an acid is [H₃O⁺][A^-]/[HA]. When the "acid" is water, HA is H₂O and A^- is OH^-. So the Ka for water is [H₃O⁺][OH^-]/[H₂O], which simplifies to Kw/[H₂O], or Kw/10^1.74. Thus, Ka = Kw/10^1.74, and pKa = 14.00 + 1.74 = 15.74.

A similar explanation applies for the pKb, and it turns out that in pure water, it must be exactly equal to pKa, or 15.74.

But isn't the concentrations in an equilibrium expression actually their activities, and for a pure liquid such as H₂O_(l), the activity is 1? 211.75.40.58 06:04, 22 December 2005 (UTC)Gaga

According to the 86th edition of the CRC Handbook of Chemistry and Physics, the pKa of water is 13.995 at 25C. The K value of the autoionization of water is 1.01 x 10^-14. The concentration of water is irrelevant because pure solids and liquids are excluded from the equilibrium constant expressions for heterogeneous reactions. Therefore, K = [H₃O⁺][OH^-] = 1.01 x 10^-14, which makes the pKa equal to 13.995.

Scott 18:50, 29 March 2006 (UTC)

No. Pure solids and liquids are only excluded from the standard K_w expression, not from the [HA] in the K_a expression. This means, when a pure substance occurs in a general expression, it is treated as having an activity of 1 even though this is simply not so. But when the expression for K_a is applied to water, the activity/molar concentration of the pure liquid does not appear on the denominator of the general expression, only the specific (when water is substituted for the acid.) This is yet another case of bad conventions causing undisentanglable confusion!!

-User: Nightvid

[edit] Magnetic property

I reverted an unexplained, unsourced, deletion of this section by an anon editor - precisely because no reason was given. I have no opinion on the accuracy or otherwise of the deleted data. How can I tell the accuracy of your source when you do not state this? Ian Cairns 22:24, 18 October 2005 (UTC)

Probably better to remove unsourced material as it makes it difficult to verify if it is correct or not. WaterGuy 17:05, 25 April 2006 (UTC)

[edit] IUPAC name

IUPAC has a proposed recommendation to name water as Oxidane. It's just a recommendation. The quoted website has jumped the gun and pronounced this as a fact. Wikipedia should not fall into this trap. Wait for the formal naming, if it is confirmed. Ian Cairns 00:15, 19 October 2005 (UTC)

[edit] density portrayal

My textbook has a marvelous concise picture illustrating why the density of ice is lower than the density of liquid water - the current articles seem to get very technical concerning this and whatnot, but doesn't seem to be obvious for the lay reader. Where would be a good place to put a picture illustrating the difference? I mean, the entire thing is after all, that the molecules of a water crystal lattice happen to because (thanks to the polar nature of water) that large volumes of empty space form between water molecules, but the articles concerning the density of water doesn't seem to refer to this obvious fact concerning the lower density. What's the best comparison to explain it verbally - I was thinking the analogy of "bonds" in the sense of strength, that if we compared water molecules to synchronised swimmers, that if they wanted to "stick together" to form bonds so they could move as one they would hold each other's limbs - and in the process of it, ending up having greater volume because well - arms and legs must be taut in order to maintain an organised bond in that situation. This is compared to a school of fish, where if they want to form bonds for safety they end up shrinking in volume. But maybe that is too colourful a description, and maybe becomes a tad inaccurate to the real bond formation, but it gives the concept to the reader that more bonds between molecules doesn't always mean a smaller volume because they are more attracted to each other and hence there is less empty space, although that's the most common effect. There somehow has to be an eloquent explanation telling the reader that molecules such as water that become have stronger attractions in colder temperatures can increase in volume because of their structure. -- Natalinasmpf 03:42, 3 December 2005 (UTC)

It sounds like a good idea, and a picture would be nice if put in the density section. However, this is the article on the molecular aspects of water, and so i don't think that creating an overly elaborate metaphor is all that useful. A picture of a hydrogen bonding scheme in water, versus a hydrogen bonding scheme in ice; or pictures labelled with bond lengths and crystal structures would be very nice, and would accurately contribute to the article. If you can think of a one sentence metaphor, give it a try. But it's a bit tricky, because these are hydrogen bonds, and so schooling fish is a bit misleading. Here's some pictures that I think might add to the article [2]. Also, these are nice articles [3], [[4]], [5]. So, for example, the liquid phase of water is amorphous and thought of as a continuum that permits many different bonding schemes, while ice generally forms into (at least locally) crystal groups with impurities; even when they are amorphous and vitreous (Amorphous ice). So, a good question is, is the density of all ice forms less than liquid water? Well, the answer is no; high density ice is more dense than liquid water. So, if you want to make a statement about the density of water, you need to set the context that you are refering to first. I will try to reword some things to make them clearer. Cypa 20:23, 3 December 2005 (UTC)

[edit] ratios

what volume of water is housing within all living organisms? and what percentage is it? also, what is the volume of a single drop, and is it proportional to surface tension? mastodon 20:11, 7 December 2005 (UTC)

Answer to all: Highly variable! -User: Nightvid

[edit] IUPAC name for water

Hi Ian, I usually hold your edits in high regard but I stumbled across this revert recently, and I was a little puzzled by it. I realise that the person posting has had his/her disagreements with the chemistry people (including myself) but this IUPAC name does seem genuine. I think this is noteworthy, and a legitimate reference was given (the ACS labs website is the standard reference site for IUPAC naming rules), so the name oxidane should be in this section. Before I put it back in, though, I wanted to check on your reasons for reverting. Thanks, Walkerma 04:53, 8 December 2005 (UTC)

Hello Walkerma, Thanks for your kind words. This reversion was a little while back. I did a Google seach on 'oxidane' and 'iupac.org' and only found recommendations / intentions. I've seen several Wikipedia articles / topics, in other areas, where intentions and proposals were reverted (one of which after formal consideration) until such time as they happen. I applied this experience to the oxidane situation. Rechecking Google just now gives only 2 hits - neither of which appears to refer to the formal adoption of oxidane as a term. Has oxidane been formally adopted? If so, do you have a citation for this? Thanks, Ian Cairns 07:19, 8 December 2005 (UTC)

http://www.iupac.org/reports/provisional/abstract04/RB-prs310804/Table6.1-3.04.pdf

http://www.iupac.org/reports/provisional/abstract04/BB-prs310305/Chapter2-Sec20-24.pdf

The name oxidane was also in the previous version of the Red Book. It is, of course, never used. Physchim62 (talk) 01:55, 3 February 2006 (UTC)

Should wikipedia redirect hydrogen dioxide to water? hydrogen dioxide would be more along the lines of hydrogen peroxide, right?

Right, I've changed the redirect for hydrogen dioxide to point to hydrogen peroxide. Itub 17:41, 22 June 2006 (UTC)

[edit] Heat Capacity

Can someone check the units for the heat capacity in the data table? Anthony Chivetta 07:30, 21 February 2006 (UTC)

[edit] Dihydrogen monoxide as a name for water

Someone added dihydrogen monoxide as "another name" for water. I don't think we should include it, because that name is never used in a scientific context. The only place it's been used is for the Dihydrogen monoxide hoax. The systematic name, if we really want one, is just hydrogen oxide. Itub 18:00, 13 March 2006 (UTC)

[edit] Hazards

I realize this is incredibly rare, but when you have trly pure water, it will dissolve things. Like you and me and metal. Isn't that a hazard?Cameron Nedland 03:38, 14 March 2006 (UTC)

I'm not sure where you got this idea from, but distilled water is completely safe. It's the Dihydrogen monoxide contaminants you have to watch out for :) GeeJo _{(t) (c)} • 05:02, 20 March 2006 (UTC)

I heard (at school) that if you drink 100% pure water, you will get very sick because it will react with different things in the stomac. Is that true ??? 07:09, 25 May 2006 [GMT +10]

I learned in science class from Coach Patterson that distilled water is only bad when it is exposed to the air because it will absorb carbon dioxide which causes it to become acidic. But when that happens it is no longer pure water, even though it has been distilled. Jecowa 20:36, 26 May 2006 (UTC)

Tap water absorbs CO₂ too. The acidity due to carbonic acid from absorbed CO₂ is less than that found in many foods. DMacks 01:58, 30 May 2006 (UTC)

[edit] Systematic naming/NPOV

The line "it is the best; some other names commonly found, such as "hydrogen hydroxide", are needlessly complicated." does not seem to represent NPOV.

- PK9 02:35, 15 March 2006 (UTC)

That line is essentially correct, although the phrasing could be improved. A general principle of systematic nomenclature systems such as IUPAC's is that the simplest possible name should be used. For example, you say propanone and not 2-propanone because the "2" is redundant. Similarly, you say sodium oxide and not disodium monoxide, or hydrogen oxide and not dihydrogen monoxide. A name such as hydrogen hydroxide (which, by the way, I'd not say is "commonly" found, although it is certainly used ocassionally for educational purposes to emphasize that water can be obtained as a neutralization product) is needlessly complicated, because it's splitting a simple binary compound in an arbitrary asymmetric way. Itub 15:54, 15 March 2006 (UTC)

[edit] Light diffraction properties

Where is there information about water's index of diffraction, etc?

Try googling index of refraction, the correct name for what I think you mean -User: Nightvid —The preceding unsigned comment was added by 130.184.111.168 (talk) 02:56, 6 December 2006 (UTC).

[edit] water as an ion

I added a part to the beggining describing water as an H+ OH- ion, as it is commonly reffered to when dealign with acids and bases

[edit] Why water is blue - a better quantum explanation ?

My teacher in physical chemistry told me that the blue color of water is because of vibrational transitions from level 1 to 7, that filter out the red light. Is that true?

Keep in mind that im answering this question as if you are talking about quantum vibrational states, etc. since you say you're in a physical chemistry class. I was taught in Pchem that vibrational transitions are quite rare, thus a transition from 1 to 7 would be exceedingly rare to witness, muchless in something as common as water. If memory serves correctly, most molecules at room temperature are in the vibrational ground state. He may have been referring to electron transitions, however, I could not say if that would filter out red light.

Uhm... well, maybe this is just my stupidity, but... isn't water just blue because of the reflection from the sky? After all, if you look at water in a glass or anywhere but outdoors, you can see that it's clear. Maianess 21:59, 19 November 2006 (UTC)

[edit] Reservoir volumes

The volumes for the different reservoirs of the water cycle differ from those at water cycle. Could do with some checking. Daniel Collins 01:30, 1 April 2006 (UTC)

[edit] Many People Don't like the taste of H2o

I am one of those people.I'd drink water if it has sugar.One of my family members said it was okay to add sugar.Do you like water?

Gemini531 20:49, 24 May 2006 (UTC)Gemini531

I like water, but tap water in some cities is gross. Some bottled water doesn't taste good either. I like the bottled water from Ozarka, Aquafina, and Dasani. Jecowa 21:14, 24 May 2006 (UTC)

[edit] Water is NOT the universal solvent

Water is NOT the universal solvent. There is no such thing. Please review your solubility rules. AStudent 06:30, 16 July 2006 (UTC)

If there was...what would you store it in? - Jack (talk) 00:00, 19 July 2006 (UTC)

A frozen block of the same substance? DMacks 02:14, 19 July 2006 (UTC)

Nope, that wouldn't work, the liquid and solid form would be in thermodynamic equalibrium with each other. The solid form would melt (disolving the thing it was on/in) or the liquid form would freeze, becoming one with its container (thus rendering it useless as a solvent).

You made me panic for a second! almost thought you'd answered one of my favourite rhetoric questions, like "what colour is paint?" - Jack (talk) 02:50, 19 July 2006 (UTC)

Yeah, was meant mostly as a mu answer. But "thermodynamic equilibrium" wasn't part of the question, nor does something have to be at a uniform temperature to have reached a steady state...what if we keep slightly cooling the bottom and maybe sides of the solid and put a small heat source just above it? DMacks 05:07, 19 July 2006 (UTC)

Could work... But as with any liquid, you couldn't stop evapouration and the vapour would condense on the cooler, corroding it a bit, then a lot, untill it eventually ceased to work. The heater would melt the block, and from then all is lost. This universal solvent; was it supposed to dissolve anything, or any amount of anything? Sounds a bit like the grey goo hypothosis to me - Jack (talk) 16:06, 19 July 2006 (UTC)

Water is called the universal solvent because it will dissolve most substances put into it, given time, if these substances are in a manageable form. Water dissolves sugar, salt, HCl... No one is suggesting that water will eat away at each and every substance on the face of the earth. All that's being said here is that most substances will dissolve in water. Maianess 22:03, 19 November 2006 (UTC)

[edit] Self Ionization

Shouldn't there be a section on self-ionization of water, or at least a proper link to that page somewhere? I'd think it is a rather important property of the water molecule and is mentioned in passing in the Electrical Properties section. Harperska 22:00, 8 September 2006 (UTC)

[edit] Specific heat error

Looks like the specific heats of water as vapor and water as liquid are reversed. Maybe just a labeling problem.

Fixed... I hope --Steven 04:18, 10 December 2006 (UTC)

[edit] Fahrenheit

I removed much of this because it stated "100 degrees was set at body temperature (now accepted as 98.6 degrees) and 0 degrees at the temperature at which equal parts of salt and water melt." This is incorrect (and somewhat irrelevant, body temperature being discussed in a water article like this?). It was initially based on the boiling point of water at 60 degrees, then he did a bunch of multiplication and wound up with 212. Zero degrees was colder than it got in Denmark (Fahrenheit hated negative numbers). See citation (at straightdope.com) for more information.Squad51 02:19, 19 November 2006 (UTC)

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