Talk:Color of water

message: From talking to many people I find that very few know that water is a blue-colored chemical.  Even science teachers don't know this, and science textbooks never mention it.  Billions of people look right at blue oceans all their lives, but without knowing...  that water is a blue substance?!  Bizarre!  How did this situation come about? --Wjbeaty 08:08, 4 September 2007 (UTC)
replies: text: The general public thinks?! --Quiddity 17:41, 4 September 2007 (UTC)

text: The term 'transparent' is a very relative term, transparency is frequency (color) dependent. All substances absorb light in some region of the spectrum. Water is no exception, but its absorption is very slight in the red end, so slight that thick layers of water are required to observe it with the naked eye. There really is no contradiction of stating that water is transparent and that it has blue color. Transparency really only means that absorption is so slight that one can still see through the material. I hope the article makes this clearer now with the new section on intrinsic color. Kbrose (talk) 03:22, 28 March 2009 (UTC)
thread_title:  Misconceptions everywhere! 

message: The article contains the following statement:
:A few tens of meters of water will absorb all light, so without scattering, all bodies of water would appear black.
But this clearly cannot be true because the Super-Kamiokande neutrino detector uses an active volume of (ordinary, not heavy) water that is "33.8 m in diameter and 36.2 m in height" and light can be seen from the center of that cylinder so at least ~16 metres away (and I think the detection scheme expects lightto make it all the way across the volume of the active cylinder).
Does anybody know the actual attenuation of visible light by ultra-pure water?
Atlant 17:28, 8 November 2007 (UTC)
thread_title:  Old Black Water 

message: Blue ice (glacial) seems an obvious candidate to become a section of this article,
which as it stands does not talk about solid water at all.
--207.176.159.90 (talk) 23:26, 25 March 2008 (UTC)
replies: text: With KR o this one -- keep it simple and findable, the blue ice I mean.  Julia Rossi (talk) 01:27, 8 August 2008 (UTC)
thread_title:  Merge proposal 

message: I was thinking of the images at http://www.eeb.ucla.edu/test/faculty/nezlin/OceanColor.htm when I added the diagram-request template. Specifically these 2 images (see page for caption/explanations)  and . However, I am not an expert in this topic, so remove the template, or point to a better suggestion if you know of one. Thanks :) -- Quiddity (talk) 17:37, 27 July 2008 (UTC)
thread_title:  Diagram request 

message: I don't see the colours "aqua" or "turquoise" in the article but they commonly used in English to describe the greeny-blue thing. Should they be included?  Julia Rossi (talk) 01:29, 8 August 2008 (UTC)
replies: text: In an article this short, it's often best to just be bold. (However, TTT userbox noticed and appreciated. Made me think of Piet Hein's Things Take Time grook (fifth one down, with his illustration even!). :) -- Quiddity 02:16, 8 August 2008 (UTC)
thread_title:  Other descriptive terms 

message: I always thought the 'grey' ocean was just a description of how it looked on a gloomy cloudy day, not anything specific to the Greek perception of color.  —Preceding unsigned comment added by 128.194.103.37 (talk) 02:34, 28 March 2009 (UTC)
replies: text: I agree. Could be added. This article doesn't have to be limited to physics. David Spector (talk) 16:42, 18 April 2010 (UTC)
thread_title:  'Grey' ocean... 

message: The science in the general discussion is wrong. The colour of a body of water that we see is due to light emitted by that body. Ignoring reflection, this has two possible origins
* Rayleigh scattering This is caused by scattering from molecules. Intensity is proportional to the fourth power of the incident light frequency, so blue is scattered more strongly than red. For example, see Blue Grotto (Capri)
*Tyndall scattering This is caused by scattering from particles. Intensity depends on particle size. Rough sea water is green due to the presense of a suspension of fine sand particles. In some alpine lakes the green colour is due to suspeded algae or bacteria.
In addition some of the scattered light may be absorbed by the fourth overtone of the O-H stretching vibration which will contribute to the blue colour.  The clearer and deeper the water the more intense the blue colour for this reason. Petergans (talk) 11:14, 15 December 2009 (UTC)
thread_title:  Colours in general 

message: Do we really need a [citation needed on] "If the oceans owed their color to the sky, they would be a lighter shade of blue, and would not appear blue on overcast days." Shouldn't it be common knowledge that every reasonable person has that the sky is not dark blue in daylight and appears white or gray when overcast? 75.66.80.108 (talk) 18:31, 29 May 2010 (UTC)
thread_title:  Completely unnecessary citation needed 

message: Is this correct? I believe the reason why water is blue in a swimming pool is due to chlorine. The volume of a water in a swimming pool should not be enough to turn water blue. Any thoughts? Valoem talk 18:28, 15 March 2011 (UTC)
replies: text: it could also be due to the color of the pool. Some pools are panted blue on the bottom.  — Preceding unsigned comment added by Tideflat (talk • contribs) 00:42, 18 March 2011 (UTC)

text: The pool in the photo is a diving pool, about 4 meters deep. I can attest that when the pool is drained, the sides are white.  water is blue because water is blue Incredio (talk) 18:57, 20 March 2011 (UTC)
replies: text: Actually, water in a pool is not enough to turn blue it is due to chlorine. You can see the evidence right from the photo. Water in the dish is clearly NOT enough to water blue, in fact a bath tub water remains clear (you can test it yourself). On wikipedia you need a reliable source before you can post uncertain information. Valoem talk 17:23, 28 March 2011 (UTC)
replies: text: In context, I think our article made it reasonably clear that the colour of pool water might be affected by chlorine or other impurities. Perhaps the caption could also mention this explicitly, although its main focus should remain on the general concept that degree of colour seen depends on the amount of water. Pure water is not common in large quantities, so if pool water, sea water, etc differ in colour, this is still a reasonable thing to cover here. I agree the article is light on sources in this section; do you know of any? --Avenue (talk) 03:58, 3 April 2011 (UTC)

text: One would imagine that the water in the bucket was scooped up from the pool. If so, the difference in colour cannot be explained by chlorine or anything else in the water. The depth of water in the pool could obviously explain the difference, but if colour depends on depth then why is the water not colourless at the edge of the pool, where one is looking through only an inch or two? A very brief experiment suggests that this may be a counter-intuitive property of coloured liquids in general. This topic needs further research. 86.176.212.216 (talk) 03:37, 26 December 2012 (UTC)
thread_title:  Possible incorrect usage of picture 

message: Kbrose removed an image that I had added, saying "rv, short lede is poor and water image does not show colorless water, too much color in background". So I am asking what should be in the background? I don't see anyway for there not to have color in the background. Even if it is white it will still be a color. Tideflat (talk) 20:32, 19 March 2011 (UTC)
replies: text: Do to the lack of response, may I add the image back? Tideflat (talk) 16:28, 2 April 2011 (UTC)
replies: text: I don't agree that "white is still a colour" in the sense meant here. A white background is neutrally coloured and would show any colour change well. So I think the image could be improved. Having said that, the image you added does show there is little colour change, so I think it would make sense to retain it until a better picture can be found. --Avenue (talk) 23:30, 2 April 2011 (UTC)
replies: text: Then how is this one instead? It has a white background. Tideflat (talk) 01:04, 3 April 2011 (UTC)
replies: text: It's okay, seems a bit over-manipulated to me though. --Avenue (talk) 02:08, 3 April 2011 (UTC)
replies: text: Here is a different one, The only problem I can see with it is that the Strawberry might distract.   — Preceding unsigned comment added by Tideflat (talk • contribs) 16:39, 3 April 2011 (UTC)
replies: text: Or perhaps it piques the reader's interest. I like it, others may not. --Avenue (talk) 22:37, 5 April 2011 (UTC)
replies: text: Then I will use it. Tideflat (talk) 23:22, 5 April 2011 (UTC)
thread_title:  Kbrose removed an image that I had added... 

message: In section 'Color of lakes and oceans' -
"It is a common misconception that in large bodies, such as the oceans, the water's color is blue due to the reflections from the sky on its surface. Reflection of light off the surface of water only contributes significantly when the water surface is extremely still etc."
So here it clearly says that the color of oceans are not determined by the color of the sky, since it is next to impossible for the ocean to be 'extremely still'. But at the end of the section:
"The surfaces of seas and lakes often reflect blue skylight, making them appear bluer."
Amazing. One of these statements obviously need to be removed.
:The first quote could perhaps be rephrased a little, but they don't contract one another. The first says that reflection contributes when the water surface is still, and the second says that reflected light often makes water appear bluer. Player 03 (talk) 02:37, 29 November 2011 (UTC)
thread_title:  This article contradicts itself!!! 

message: Okay, regarding this material, I'll be more specific.
*"the water in a swimming pool also appears blue even when the optical path length through the water to the white sides is mere millimeters"
The optical path length hasn't been measured in this setup.
*"evidently reflection at the air-water interface shifts the source of illumination to light that has traversed a large distance through water"
That's not evident; in fact, it doesn't make sense geometrically.
*"as demonstrated with a floating white bucket with water in it"
This is a synthesis of multiple observations made to argue a point.
*"Popular belief is that the blue color must be intensified by the presence of chlorine"
There is no evidence that this is a popular belief. 
*"The lack of blue color of the water in the bucket could be hypothesized to be due to the catalytic destruction of the popularly-believed chlorine coloring agent by the plastic of the bucket"
This is speculation for the sake of argument.
*"more conventionally the explanation relies on the greater optical path length for the deep swimming pool as compared with the shallower bucket"
This isn't a novel interpretation, but it does conflict with the "reflection" argument above. Melchoir (talk) 06:20, 5 October 2011 (UTC)
replies: text: The above changes are reasonable. Incredio (talk) 02:19, 6 October 2011 (UTC)
thread_title:  OR in swimming pool 

message: Sorry if this is a silly question, but I feel it needs explanation. In the section "Intrinsic color", the "harmonic" v1 + 3v3 = 14,318 cm−1 is the one that is said to be responsible for the behaviour of water molecules in the visible spectrum when v1 = 3650 cm−1 and v3 = 3755 cm−1. However, simple calculation shows that the sum is 14915 cm-1, which corresponds to a wavelength of around 670 nm. The difference appears to be significant on the spectral scale. I checked the reference cited, but the authors of the paper have not explained the anomaly. Nowhere have I been able to locate any justification for such a glaring approximation. Now, although 670 nm still is within the range of red spectrum, it certainly isn't "at the edge" of it, as claimed in the paper. Am I missing something? Why would there be such an error? Does it make a difference? Should other sources be cited? Knaveknight (talk) 08:22, 7 November 2015 (UTC)
thread_title:  Unexplained calculations 

message: I don't dispute that many lakes, rivers, etc. look green from Biological bodies but that particular color green is entirely different from the Emeral/Jade green viewed at many alpine lakes, rivers. Of which, where I grew up, was always attributed to the dissolved Gneiss in the water. And there isn't much Biological to make the water green at altitude. Moreover, they should appear reddish brown from the tannins if anything. For example, zooming-in to many of the Cascades alpine watersheds closely and they do indeed appear green, rather than the blue initially. 80.5.219.60 (talk) 17:58, 26 January 2016 (UTC)
thread_title:  No mention of Alpine Lakes and Creeks water looking Green. 

message: In other words, is this American English Wiki or English wiki? RoclorD (talk) 20:19, 7 December 2017 (UTC)
replies: text: Either. Per WP:TITLEVAR, we don't currently change the title once the article is created if it doesn't matter. Erik Humphrey (talk) 07:40, 26 January 2021 (UTC)
thread_title:  Color or colour?