Talk:Water/Archive 1

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the "ice skates liquify ice" myth

Should we mention this myth in the article ?

http://www.eskimo.com/~billb/miscon/miscon4.html#ice

http://www.princeton.edu/~lehmann/BadChemistry.html#Skating

Well, the criticism is partially wrong. True, you need more than pressure to liquify ice. I guess is has more to do with friction. But take head: ice skating is only possible because you liqify the ice under your skates. At about -40 celzius, you can't do that any longer, and skating becomes very tough. If not for that effect, Scott's mision to the south pole might have came back alive. User:mousomer

> Furthermore, pressure applied to ice will liquefy it, which makes ice skating possible.

I don't think this is actually true: it is a common instance of folk-science. Consider, ice is still very slippery even if you're not wearing skates. Also, it's possible to "skate" with ice skates, or shoes, along cement (though quite a bit more difficult because of friction). I certainly agree that ice will phase transition to a liquid under higher pressure, evidenced by the negative slope of its phase boundary curve. I think the bit about ice skating should go, perhaps even replaced by a note to dispell this myth. More data also welcome, as I'm not completely positive. mimirzero 04:26 Sep 13, 2002 (UTC)

I think the sentence is correct. The reason that ice is slippery without skates is that you press on it; the reason that it's more slippery with skates is that the pressure is higher. Cement is not liquified by the body's pressure, so you can't skate on it: normally, pressure increases the frictional force, but in the case of water it reduces it. But I'm also not completely positive. AxelBoldt 02:01 Sep 14, 2002 (UTC)

Nope, the sentence above is quite false. It's true that pressure does decrease the melting point of ice, but it would take tons of pressure to melt ice at temperatures routinely skated at, so that's not what makes skating "possible". There's actually not much good research in this area, but the best prospects so far include a phenomenon known as "surface melting" where the atoms at the surface of a solid behave in liquid-like ways, regardless of the temperature and pressure; and possibly some heating of the ice by the friction of the blade. One can skate on dry Teflon, BTW.

We would need the force per area that melts water at skating temperatures; even if the force is large, the small area of the skate could do the trick. Also, the Teflon skating seems to work completely differently, since no melting is involved. It would be more interesting to know if it is possible to skate on materials with comparable melting point to water, but which do not show the pressure-melting point relationship of water. Frozen hexane, maybe? AxelBoldt

Data from CRC, 77th ed. : water: ice I - liquid phase boundary: { pressure (MPa), melting point (°C) } : {0.1,0.00}, {1.,-0.06}, {2.,-0.14}, ... {50.,-4.02}, ... {100.,-8.80}, ... {150, -14.40}, ... {200, -20.69}

Data from www.ice-rinks.com/FAQ.htm : ice temperature { hockey, -8.8°C }, { figure skating, -3.3°C }

Data from www.angelfire.com/sd/scsa/scsa.html : speed skates : dimensions { width, 1.1-1.4mm }, { length, 330-457mm }

Assume 65kg adult. Assume -5°C ice and ambient. Assume 1.2mm x 400mm skate blades.

Use g=9.8m/s², F=m*a, P=F/A, A=l*w.

Derive: P = m*a/(l*w) = 1.33 MPa.

Extrapolate ice's MP from data for 1.33 MPa: ~-0.09°C.

Conclude: -0.09>>-5.0°C: Human mass is vastly insufficient to melt ice.

Action: removing skating reference from article

Question: maybe post myth-dispelling math somehwere (and find non (C) source for data?)

mimirzero 04:57 Sep 14, 2002 (UTC)

Conclude: mimirzero is possibly a robot.

Action: Get horribly confused. PMcM 16:32, 19 Sep 2004 (UTC)

Conclude: mimirzero is possibly an alien from a parallel universe known as a physics teacher!

Conclude: PMcM is a typical physics student : constant state of confusion :-)

I thought it was a good presentation, but I'm a chemistry teacher. I think a discussion of this would be good in a skating or ice article rather than in water. See this also for a good discussion of the phenomenon.--Vsmith 19:46, 19 Sep 2004 (UTC)

You are assuming constant pressure across the area of the blade. If the skater's weight is not evenly distributed, perhaps it's conceivable that you could routinely get 50 times the pressure you calculated. Also, hockey skates are concave, so only the two outer edges are ever in contact, which makes the area much, much smaller, and the pressure correspondingly higher. --P3d0 19:53, Sep 19, 2004 (UTC)

I think a more important assumption missed is that ice skates are razor sharp, which allows for a much smaller contact area, resulting in a much higher pressure. Martin Rudat(T|@|C) 14:42, 27 September 2005 (UTC)

desert survival

> Desert survival

Why is this whole section here? Seems like it should be under "Desert Survival" or "Construction of a Still" not "Water". And I don't think Wikipedia should be a repository for how-to-build-it's either, but that's just me. I'm voting to remove this section. mimirzero 05:25 Sep 13, 2002 (UTC)

Procedural information has its place in Wikipedia, but I agree that it's out of place in this article. AxelBoldt 02:01 Sep 14, 2002 (UTC)

I'd have to vote to move this section to a more appropriate area. WaterGuy

> Warning

Ok, maybe I'm just in fanatical-cut mode, but I also don't think Wikipedia should be in the buisiness of prescribing certain behaviors and admonishing others. I think the warnings should be reworked to simply present the facts preferably in the main body of the article. And the alcohol warning should really go under "Alcohol" not "Water" IMHO. I propose that the warnings should instead be dropped: consider if we started putting in things like "Do not use water on a metal fire" "Do not try to breathe water" All these are true, but Wikipedia is not an MSDS database.

Or the discussion of "desert survival" should be shifted to an article on the topic. Robert Merkel 05:35 Sep 13, 2002 (UTC)

Drinking water on this page links to the same article as Water (resource). Ellywa 09:20 20 May 2003 (UTC)

What's the bond angle of water? Would it be appropriate to put a 3D model of H20 on this page? I'm just playing around with POV-ray modeler and I was trying to make a molecule using the "blob" feature. But then I needed to know the bond angle of H20. That brought me here, and then I had the idea to put a 3D picture of H20 on this webpage. If I can think of a consistent way to translate empirical bond length/bond angle stuff into a 3D picture then that would be cool. Although there are speciliazed programs which can do this already, like RASMOL, but POV-ray code seems so damn simple. dave

potable

along the lines of what was mentioned earlier... but clicking on "Potable" in the article (something like "water that is fit for human consumption is called potable") links to this article... that seems kind-of not helpful, but I really don't know what else should go in the potable article... thoughts?

In the dutch wikipedia the article on potable water contains info on dutch regulations on drinking water, in addition, the history of the devolpment of drinking water might be added in future. Ellywa 21:07, 14 Aug 2003 (UTC)

So... somebody should probably translate the Dutch article (and probably put some regs from other countries in as well), yes? -- SS 19:05, 14 Sep 2004 (UTC)

Thermal properties of Water

I forget the terms as it was a long time ago, but should there not be details on the thermal properties of water here - heat needed to raise 1 kg by 1 degree C (or whatever), and also that needed to change phase (solid-liquid, liquid-gas) ? A note on the definition of the calorie/Calorie may also be appropriate.

Any "qualified" volunteer ?

Amused?

The water dipoles hydrogen bond to the dipolar regions of the sugar molecule and allow it to be carried away into solution. "HELL YEAH"

I must be the only that finds this anon's enthusiasm about aqueous solutions amusing, right? -- SS 18:57, 14 Sep 2004 (UTC)

Pressure-temperature state chart

A pressure-temperature chart showing the regions where water is in each state would be awesome, and make the triple point discussion more obvious. The colour could even add some extra info, such as density. Does anyone have relevent formulas that could be used to produce such a graph, if not such a graph itself? Derrick Coetzee 00:26, 19 Sep 2004 (UTC)

Freezing salt water???

I'm uncertain about the following:
"Note that this effect only applies to fresh water: sea water contains sufficient salt that the density minimum occurs at the freezing point (approximately -1.9 oC)."
This short note by itself would seem to imply that the Arctic Ocean should be frozen solid top to bottom! We need to include a bit here about salts "freezing out" as salt water freezes. The resulting ice is less salty and less dense than the salt water it freezes from. I'm not familiar enough with the details to feel qualified to edit it until I have time to delve deeper into it. --Vsmith 01:48, 19 Sep 2004 (UTC)

(William M. Connolley 08:49, 19 Sep 2004 (UTC)) OK, will do. (William M. Connolley 08:52, 19 Sep 2004 (UTC)) Oh no I won't... its been done. Should have checked.

Was this major split & rewrite needed? Maybe discuss first.

I think this split & rewrite just made things more confusing. Many parts of the orig version need to be included in both of the new splinters - and quite a bit is in the wrong place. My first impulse was a quick revert, but maybe we need to discuss it - as would have been appreciated before this split.--Vsmith 21:17, 19 Sep 2004 (UTC)

I disagree with the rewrite altogether. The chemical properties of water are very closely tied to our daily experiences with it, and the text went out of its way to discuss these ties. Just because you're not a chemist doesn't mean you don't care why the lakes don't freeze solid, why salty water boils hotter, or whether water conducts electricity.

More controversially, I think a featured article candidate should see only relatively small changes until after it's featured.

While I'm not suggesting an outright revert, I do suggest that we revert and that anything the new editor added be merged into the reverted article. I'd like to hear the editor's voice on this though. Derrick Coetzee 22:40, 19 Sep 2004 (UTC)

Actually, this major rewrite was discussed in the feature article candidate page, where the candidacy was mostly opposed. The consensus was that the page was confusing as it was, and no satisfactory structure had been found. It seemed that the only way out was to clearly distinguish "water for life" and "water (molecule)". I believe that these are 2 very different concepts: drinking water, and pure water. (sorry for the lack of advanced warning in this talk page. I'll learn to be more careful in the future) . Please consider that this is work in progress: feel free to move things from one page to the other, or rework as you wish. Pcarbonn 06:30, 20 Sep 2004 (UTC)

I withdraw my objections. This seems like it was a pretty good move, as long as there's a prominent link for people with more chemistry background. Derrick Coetzee 00:32, 2 Oct 2004 (UTC)

One has to remember, that ultimately its chemical properties allow for the rest of its benefits, so I think we should do as always the standard format: one main water article, then branch off into subarticles. -- Natalinasmpf 13:37, 19 October 2005 (UTC)

Here is the discussion from the Feature Article Candidate page:

(self-nomination) This article covers a lot of ground (or should I say "water" ?), and anybody can learn something from it. Pcarbonn 15:10, 18 Sep 2004 (UTC)

Oppose: none of my suggestions were even commented on in peer review. Specifically, I'm confused with the diagram. What does it mean? Could you add more information onto the actual image itself? Could we also fix up the 1 sentence paragraphs? Some of the paragraphs could be fleshed out, say for instance "The Mpemba effect is the surprising phenomenon whereby hot water can, under certain conditions, freeze faster than cold, even though it must pass the lower temperature on the way to freezing." - give a bit more info (not the entire article it references, just some more info to make it more complete). Also, the history seems tacked on as an afterthought. I mean, there's water->History->Mythology and water->Water in practice->Water in religion... get my drift? Otherwise, this is a really well researched, well-written article! I would be happy to support it if you can sort out these things (especially a structural organisation). - Ta bu shi da yu 16:26, 18 Sep 2004 (UTC)
- Woops ! Somehow I lost your feedback in peer review. Sorry for that. I think that some of your objections have been fixed. Still working on the others... About "expanding 1-sentence paragraph": I'm afraid that the article would be much too long if we did that. It's already quite long as it is. What do you think ?Pcarbonn 16:53, 18 Sep 2004 (UTC)
  - Hmmm... better, but I still object to one sentence paragraphs - doesn't look that professional. But not too bad. Seems there are a few more objections we could work on though. Now that I'm not concentrating on my exploding whale story so much, I can look into this story. - Ta bu shi da yu 13:57, 20 Sep 2004 (UTC)

Support: Very good article. I just re-arranged a bit, joke section & religion - hopefully an improvement. Always work to be done, red links ... etc. --Vsmith 16:38, 18 Sep 2004 (UTC)

Object--until the following fixes are made. 1) The Mpemba effect does not belong in the "Water properties" section--because it is not clear what water property causes the Mremba effect. Perhaps you should move the Mpemba effect to a section "Oddities about water." 2) What do you mean by "Water in practice"? This heading sounds like "Communism in practice" as compared with "Communism in theory." Come up with a better heading, please--Maybe something like "Water in everyday affairs." 3) The anthropic principle has no place on the Water page. Take it off. The special properties of water apply to all lifeforms--not to just to anthropoi men. 4) The content of "Systematic Nomenclature and Humor" has nothing to do with the Physics and Chemistry of Water. So you might move it to "Oddities about water." 5) Fire, air, earth, and water is not mythology. That theory by Empedocles was "the theory" used by Aristotle to explain the difference between water and wine. Empedocles's theory was an early form of the idea that matter was formed from unseen elementals that were not created and will never be destroyed. [1] Perhaps you should retitle this section as "Water in early philosophy." 5) The order of the First section (which I will call "Water in everyday affairs") does not make sense; the sections are disarranged, with no logical order. Perhaps you could reorder this section to fix it by sequencing the sections from personal data toward Universal data to give the following order: Forms of water, Water properties, Water in life, Drinking water and politics, Domestic and industrial use of water, Water on earth, Water in the universe. I like the potential of this article, and I think you have done a marvelous job of making this a very interesting page. Congratulations! ---Rednblu 20:28, 18 Sep 2004 (UTC)

Object: The article's organization seems very focused on chemistry. I think that someone with no chemistry background would get through the introductory paragraphs of the article, and then founder on "Forms of Water". The chemical information is definitely important, but I think that there's a lot more that can be said -- I think information about the ecology, biology, etc. might want to go first. I think that you should split the "Properties of Water" section -- some of the basic information would be appropriate at the beginning of the article, but things like electrolysis, the Mpemba effect, and other chemistry-specific information would be better later. Also, I think that having one of the photographs at the beginning of the article, and pushing the box of chemical information farther down the page, would make the article easier to read. Basically, remember that many of the people reading the article aren't going to be physicists or chemists; technical information that most readers won't be interested in should be sectioned off, or even put into its own article (Chemical Properties of Water, perhaps) -- Creidieki 01:28, 19 Sep 2004 (UTC)

Shouldn't "Water in religion" and "Water in mythology" be merged? -- Emsworth 02:10, 19 Sep 2004 (UTC)

Definitely. - Ta bu shi da yu 14:00, 20 Sep 2004 (UTC)

Object - This subject should be a feature article, but at the moment it shows strong signs of committee editing. Too much of the information is in short single fact sentences. To be considered best writing, many of these factoids should be grouped together and discussed in a more flowing style. I agree with many of User:Rednblu and User:Creidieki's comments, but:

The anthropic principle should be mentioned in relation to the properties of water around 4°C. The problem is that too much of the rest of the article focuses on extraterrestial water. In particular, way too much in the lead section.
The Mpemba effect: in or out - I could go either way. Perhaps in a 'see also'.
A picture of an ocean, or waves crashing on a craggy shoreline would be good.
The pictures are moving around, but I would have thought a pic or a reservoir would be better than the shower.
Talking of showers, there is almost no mention of the use of water for washing and cleaning, except in the religion section. That's a little off.
Talking of reservoirs, why no mention of them or aquifers or anywhere else we get our water from. Or bottled water.
History section is rather poor. Could be good to merge the religion and early philosophy subsections, along with various views on water as a life force. Similarly should discuss spiritual associations attributed to rivers and springs. E.g. Nile, Gangees and Sulis.
No mention of the recreational use of water.

Of course, if you put in all these ideas, someone would say the article is too long and it has already had various sections split out. -- Solipsist 07:56, 19 Sep 2004 (UTC)

Thanks for the feedback. I'll split the article in 2 : water in (everyday) life, and water (molecule). I'll resubmit to FAC when done. Pcarbonn 16:15, 19 Sep 2004 (UTC)

Cool! I sometimes miss these things, message me on the talk page when you do. Please :-) - Ta bu shi da yu 14:00, 20 Sep 2004 (UTC)

Important properties for life

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)

OK, then put it in human culture or a Philosophy & Religion section. But, not in the main descriptive sections.Vsmith 16:52, 24 Sep 2004 (UTC)

Neither the anthropic principle nor a fine-tuned universe imply intelligent design; they can only support it, and either may be irrelevant to the idea. They can be expressed scientifically, and frequently are, and they're "unfalsifiable" because they are true. You're certainly free to try living in a universe with different physics or composition, or on a random starless planetoid. In this universe, however, the peculiar coincidences of its existence make it very conducive to matter; the coincidence of Earth being where it is gives it conditions suitable for biological processes; and the aberrant behavior of water makes it especially conducive to life.

The argument, boiled down, is:

The conditions in the universe favor our existence.
Small variations in the conditions would make our existence impossible.
In fact, almost any conditions would prevent us from existing.
This universe is freaking weird.
Our universe is weird because we're part of it.

Therefore the anthropic principle is your own fault, so don't complain. --[[User:Eequor|η

υωρ]] 06:41, 6 Nov 2004 (UTC)

... and they're "unfalsifiable" because they are true. Wow! That sounds like a religeous statment to me. It's true: all you gotta do is believe. To be scientific an hypothesis must be testable or falsifiable. No way to test or falsify = not scientific. -Vsmith 17:00, 8 Nov 2004 (UTC)

Yes, well, observed facts are inherently true. Science is only concerned by why particular observations occur, not by whether the observations themselves have occurred. It cannot change the facts, only interpret them.

Hmm... observed facts are not inherently true. Observed facts are our current interpretations of our sensory perceptions or our instrumental measurements of those facts. Thus these facts are subject to sensory and instrumental error and are not inherently true. Facts, except perhaps the most trivial kind, are subject to re-interpretation and re-measurement by more sophisticated instruments. The facts can and do change with new interpretations based on new theories and explanations undreamed of in previous times. -Vsmith 00:56, 9 Nov 2004 (UTC)

What I mean is, an observation has a definite existence, regardless of our interpretations. Someone who observes the sky to be blue will always have that observation in their history. It is true that they observed a blue sky. --[[User:Eequor|η

υωρ]] 17:13, 11 Nov 2004 (UTC)

The anthropic principle is simply a truism. Because we observe only the universe, the universe must be in a state that allows us to observe it. Such a statement is self-verifying and cannot be false.

A truism ... had to look that up as I don’t normaly use the term.

Found: A trite expression or idea: banality, bromide, cliché, commonplace, platitude...

and ... Often the word is used to disguise the fact that a proposition is really just a half-truth or an opinion, especially in rhetoric. from the Wiki article.

So, why would we even use the phrase - as it is indeed either a trite expression or just a half truth. I say be gone with it, not worthy of an article nor any kind of argument. -Vsmith 00:56, 9 Nov 2004 (UTC)

Fine-tuned universe is a corollary to the anthropic principle. There is exactly one set containing every observation we have made or will make, in sequential subjective order. Essentially, one's observed universe is "fine-tuned" for one state -- exactly that state which is observed -- to the exclusion of all other possible tunings. It is unnecessary to refer to any specific properties of the universe; all other formulations of this idea concern the same set of observations. Again, this statement is a truism.

The Universe we observe simply is and is not fine-tuned for anything. That would imply a tuner out there somewhere - an unknowable. The Universe is as it is. Life in the Universe has developed and evolved in and with the conditions of the Universe and has therefore tuned itself by evolution to the specific characteristics of the Universe that simply are. You state that fine-tuned universe is a truism. Again, be gone with the trite expression. -Vsmith 00:56, 9 Nov 2004 (UTC)

It is, however, worth noting that water is necessary to our existence. Thus, we can also make stronger statements about the fine-tuned universe. Since water is necessary for our existence, the set containing our history must contain water. --[[User:Eequor|η

υωρ]] 17:25, 11 Nov 2004 (UTC)

In other words, anthropic principle and fine-tuned universe are invariant truths for all observers. It makes no more difference whether one believes in them, than whether one believes in one's own existence. Each observer can verify the statements' truth by carefully conducting thought experiments about what, exactly, consciousness and self mean.

Thought experiments, good mental excercise. Didn't think we were discussing consciousness and self. Different horse, different ride :-) -Vsmith 00:56, 9 Nov 2004 (UTC)

But of course we are! ^_^

Must not all observations be observed by a self and interpreted by a consciousness? --[[User:Eequor|η

υωρ]] 17:19, 11 Nov 2004 (UTC)

The idea that falsifiability is somehow necessary to the scientific method is an unfortunate but widespread error. Science survived quite well before the 20th century. The possibility that an observer's interpretation of their observations is based on incorrect assumptions is irrelevant to their existence. If a reasonable observer does, in fact, observe their interpretation is flawed, they will discard assumptions which have been demonstrated to be incorrect. An unreasonable observer will discard the observation as spurious. Neither has any inherent interest in knowing in advance whether they will make a contradictory observation.

In particular, thermodynamics and relativity both refute the idea that "falsifiability" means anything at all. --[[User:Eequor|η

υωρ]] 19:59, 8 Nov 2004 (UTC)

The idea that falsifiability is somehow necessary to the scientific method is an unfortunate but widespread error.

Nonsense. A scientific theory or hypothesis is worthless if it cannot be tested. It must make predictions that can be tested, in other words - falsifiable - there must be a way to check its validity, to see if it is error. Other scientists must be able to either reproduce the results or falsify the theory if they cannot. Einstein’s relativity theory has been tested repeatedly on various points. It is a scientific theory because it makes predictions that can be and have been tested. But, then I gather from your responses that you really do not know what falsifiability means. -Vsmith 00:56, 9 Nov 2004 (UTC)

Falsifiability isn't the same as verifiability. One can verify the truth of a hypothesis without needing to know whether it could be proven false with other knowledge. One can also act on the discovery that a hypothesis is false without prior awareness that it could have been false (and, at that point, "falsifiable" becomes a truism anyway). There is no particular reason one might need to know whether something can be proven true or proven false; one must only be able to state conditions which are sufficient (truth) or necessary (falsehood).

In the case of the anthropic principle, a sufficient condition for its truth is the fact that we observe the universe. One might say that fine-tuned universe is concerned with stating the necessary conditions for us to exist. --[[User:Eequor|η

υωρ]] 17:01, 11 Nov 2004 (UTC)

Fats in evolution

Also, could some one explain to me why the following sentence was "not making sense", and therefore removed ? "Fatty substances can also create membranes, separating an "inside" from an "outside". This allows the creation of individual cells, their competition for resources, and the process of evolution through natural selection". Life without cells wouldn't be life, right ? Thanks. Pcarbonn 18:24, 23 Sep 2004 (UTC)

I put back in -- makes sense to me. However, it may need a tie in sentence for clarification.--Vsmith 22:14, 23 Sep 2004 (UTC)

It's vague and makes unfounded claims:

Fatty substances can also create membranes, separating an "inside" from an "outside".

"Inside" of what?
How is this relevant to properties of water?
Why must cell membranes be composed of hydrophobic substances?

This allows the creation of individual cells, their competition for resources, and the process of evolution through natural selection

This suggests that cell membranes are composed only of lipids.
It jumps to the conclusion that cells compete for resources, and that competition at the cellular level is the basis for natural selection.
It claims natural selection is required for evolution.
The argument that evolution is required for life belongs in a different article; why imply that here?
How is this relevant to water?
If water is a significant part of natural selection, the connection probably deserves more than a single sentence.

Life on earth has evolved with and fine tuned itself to the important features of water.

Water does not evolve.
This is the conclusion of the section; in what ways has life fine-tuned itself to water? The preceding paragraphs do not discuss that.
This appears to be a misunderstanding of the idea of a fine-tuned universe, and if that was the intent, it is backwards. The properties of water appear fine-tuned for the development of life; life is not necessarily fine-tuned for water (see extremophile).

--[[User:Eequor|η

υωρ]] 05:46, 6 Nov 2004 (UTC)

No - water doesn't evolve (I didn't say that) - living things do. And they did evolve to utilize the many neat properties of water. This is an exact understanding of fine-tuning in the universe. Living organisms evolved with and fine-tuned themselves to utilize all the neat physical properties of their environment. Yes, extremophiles fine tuned themselves through evolution to adapt to and utilize some pretty bizzare environments where they had little competition. They still utilize water. -Vsmith 17:14, 8 Nov 2004 (UTC)

Unusual properties

Please note that water's part in the greenhouse effect is not unusual, nor due to its polar nature, nor even necessary (despite its prevalence). One might easily imagine dust clouds which reflect, rather than trap, heat. --[[User:Eequor|η υωρ]] 05:52, 6 Nov 2004 (UTC)

This is incorrect. Water accounts for nearly all of the atmospheric greenhouse effect despite the fact that it is a trace element in the atmosphere. The reason is that it is largely transparent to visible light, but readily absorbs outgoing infared radiation. I cite /Global Physical Climatology/ by Dennis L. Hartmann --dikaiopolis

Opacity to infrared light isn't particularly notable, is it? Lots of compounds block that. Is water unusually opaque to infrared for its transparency to visible light? --[[User:Eequor|η

υωρ]] 06:51, 6 Nov 2004 (UTC)

Incidentally, you've used the word extreme very many times, as well as a doubly emphatic extremely crucial. --[[User:Eequor|η

υωρ]] 07:03, 6 Nov 2004 (UTC)

Well feel free to edit my emphasis. But no, opacity to infared light is *the* mechanism of the greenhouse effect. And no, not very many compounds in the atmosphere *absorb* (not "block" -- energy is absorbed) infared, precisely because they have no dipole moment. If you look at common atmospheric compounds -- N2, O2, CO, N20... none of these have dipole moments, and have very low absorptivity in infared bands. If you want to learn about this, look up my reference which should be available in your local library. Page 48 shows a nice graph of absobtivity of atmospheric compounds as a function of wavelength.

The criterion for whether a molecule abosrbs infrared is not whether it has a dipole moment, but whether that dipole moment changes as it vibrates. For example, carbon dioxide does not have a dipole at rest, but some of its vibrational modes give it a dipole that fluctuates about zero. Shimmin 12:02, Mar 28, 2005 (UTC)

Also, you could take a look at the first hit on google: http://www.everythingweather.com/atmospheric-radiation/absorption.shtml -- "Absorption is mainly caused by three different atmospheric gases. Contrary to popular belief, water vapor causes the most absorption, followed by carbon dioxide and then ozone." I also know that carbon dioxide is orders of magnitude less absorptive because it only has a dipole moment when one of its degrees of freedom is excited, where as water has a dipole moment always.

Oh, I see. That's very interesting! Is water's absorption expressed by its dielectric constant, or is that slightly different? How is its permeability related? --[[User:Eequor|η

υωρ]] 13:15, 6 Nov 2004 (UTC)

They not really related. I'd be happy to explain to you the general message on IRC or E-mail. The short answer is that it has to do with electric dipole moment. Electric dipole moment may be related to dielectric constant in some tricky ways, but it is not really relevant here (that I can see offhand). Also, I took a look at the greenhouse effect page, and it has some info on the relative absoptive effects of the various greenhouse gasses. It's not a very complete explaination -- it turns out that it matters specifically *what* type of radiation water absorbs -- but the gross picture is there. -- dikaiopolis

Table

Howdy y'all,

i havent edited this page before, so before i rush in and do something ill run it pass you all, in case there is some consensus about it that i dont know of. What do people think of the table on the spanish article for water (obviously translated into english) for this page? The bellman 00:37, 2004 Nov 30 (UTC)

Hi - check out water (molecule) the technical page that was split off this a month or so ago. It has that table - which used to be here. Seems someone thought it was too long so it was split. -Vsmith 02:23, 30 Nov 2004 (UTC)

Deltas

When describing a delta, it uses delta as a plural word. Is this correct?

Etymology

Are you sure the word is borrowed from Low German, isn't Old English wæter a more plausible origin?

Spelling Style

There have been recent edits switching back and forth between American and British spellings, esp. color/colour and odor/odour. Comments:

Failing to decide on whether we use American or British style can result in a lot of back and forth edits to no real purpose. Guidance: Wikipedia:Manual_of_Style#National_varieties_of_English
If we settle on British style, it should be consistent - hence vapour instead of vapor.

--WCFrancis 14:54, 3 Jun 2005 (UTC)

Policy dictates that the first major contributor's spelling should be the preferred style of English. I would consider this to be the first major contribution, which would favor American English, but a case could also be made for this as being the first major contribution, which would favor Commonwealth English.

It seems now that we need to decide which version constitutes the first major contribution. Failing that, we could always try to reword some passages so that they need not favor any dialect of English.

Darrien 21:00, 2005 Jun 3 (UTC)

What is it called?

When you place water in a beaker, the water around the inside edge rises up to a higher level, due to presumably being attracted to the beaker. This can be seen in the article on beakers. Does this effect have a name?

       Nevermind, I found it, it is the cappilary effect

Gaia Hypothesis

What does this mean? "It has been proposed that life itself may maintain the conditions that have allowed its continued existence. The surface temperature of Earth has been relatively constant through geologic time despite varying solar flux, indicating that a dynamic process governs Earth's temperature via a combination of greenhouse gases and surface or atmospheric albedo. See Gaia hypothesis." I'm tempted to delete it, but I'm worried someone's attached to this idea. In particular, I'm confused by the sentence "It has been proposed that life itself..." what is "life"? Last time I checked it was a condition that things are in, not an entitiy in and of itself. James 23:01, July 16, 2005 (UTC)

Taste

Many bottled water companies exploit another common misconception, advertising both purity and taste, even though pure water is tasteless.

Well it is partly true, I have noticed that some brands taste less matalic then others. --68.6.29.194 06:47, 17 August 2005 (UTC)

Origins of Water

I would be interested in seeing this article expand to incorporate a discussion of the origin of water. I recently came across a statement by Masaru_Emoto about a finding by NASA and the University of Hawaii in 1997 that ALL water originally came from comets. Greenman 22:20, 23 September 2005 (UTC)

Crisis?

Removed the following:

----

The Crisis

Let us now look at some of the diffrent dimensions of this crisis.

About 120 crores of people (20%of the global population) spread across 40 countries do not have access to safe water;240 crores of people lack adequate senitation srvice

Don't have a clue what a crores of people means. If a source exists, then cite it, clean-up the wording and re-insert in the proper location in the article. Vsmith 00:02, 27 September 2005 (UTC)

External Links

[2] - Dihydrogen Monoxide Research Division, anyone? It's at least somewhat apropos. Martin Rudat(T|@|C) 15:02, 27 September 2005 (UTC)

"Exploit[ation]"