Molecules: You'd better learn to live with them.
I love stuff like this. A lot of people don't believe that water is blue until they see some really clean water. It really is, though, and the reason is simple yet fascinating. It is because water is blue - very faintly, it's a unique phenomenon because you don't see 10,000 gallon pools of methanol (etc.).
D2O, for example, is not blue.
To see some really brilliantly blue water, take a look at these incredible frozen wave glacier pictures.
Thanks for all the corrections; here is some moving water that does freeze.
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Comments
snopes.com did an investigation on that last link. The photos are from Antarctica, not Lake Huron.
Posted by: andy | May 27, 2008 10:18 AM
The Physics and Chemistry of Color, Kurt Nassau, p. 73. Graph of optical absorption coefficient of water vs. energy. Water has signficant optical absorption from the near-IR through 2.2 eV.
http://www.medphys.ucl.ac.uk/research/borl/homepages/veronica/thesis/chapter5.pdf
http://omlc.ogi.edu/spectra/water/data/hale73.dat
http://omlc.ogi.edu/spectra/water/data/buiteveld94.dat
http://omlc.ogi.edu/spectra/water/data/warren95.dat
better
Pure water is pale blue.
Posted by: Uncle Al | May 27, 2008 11:27 AM
The pictures are beautiful, and I have no doubt that water is blue, but the pictures are not of frozen waves in Michigan. They are glaciers in Antarctica.
http://www.snopes.com/photos/natural/antarcticwave.asp
Posted by: Miss Cellania | May 27, 2008 12:38 PM
You may want to look into the "frozen wave" story a bit more closely. This site has a different view on the story.
http://urbanlegends.about.com/library/bl_frozen_wave.htm
Posted by: DT | May 27, 2008 1:23 PM
Along the same lines isn't sky blue, because air is blue
Posted by: thethyme | May 27, 2008 1:52 PM
Those are not frozen waves, they're melting glaciers!
http://www.snopes.com/photos/natural/antarcticwave.asp
Posted by: Tanath | May 27, 2008 5:53 PM
Those aren't frozen waves, just regular icebergs.
http://www.snopes.com/photos/natural/antarcticwave.asp
Posted by: Nathan | May 27, 2008 5:56 PM
Here's some more nice pictures of frozen (mostly) blue water: striped icebergs!
http://www.dailymail.co.uk/sciencetech/article-536928/Revealed-The-Antarctic-iceberg-looks-like-giant-humbug.html
Posted by: Miss Cellania | May 27, 2008 10:13 PM
@ thethyme - Water is blue because it absorbs in the red part of the spectrum. The sky is blue during the daytime because of Rayleigh scattering, which is also what causes the sky to be red at the horizon at sunset.
http://en.wikipedia.org/wiki/Rayleigh_scattering
Posted by: fullerenedream | May 28, 2008 12:47 AM
agreed about the red spectrum, The outline of science has an excellent section on this, http://www.theoutlineofscience.net/
Posted by: Daniel Sroda | May 28, 2008 7:05 AM
Actually, the sky is blue because of a combination of Rayleigh scattering and the weakness of human vision in the blue/violet end of the spectrum. Otherwise, spectrally it should be purple.
Posted by: saurabh | May 28, 2008 11:07 AM
my bad I pulled that from an old SGU episode and the only thing I found to back that up is this site
http://www.amasci.com/miscon/miscon4.html#blu
I am not sure if this is accurate or not but I have doubts not finding any additional information to support this position
Posted by: thethyme | May 28, 2008 3:10 PM
My emeritus colleague Chuck Braun has a good answer:
"To our knowledge the intrinsic blueness of water is the only example from nature in which color originates from vibrational transitions." (link)
Posted by: barney | May 28, 2008 3:47 PM
I don't understand how people could not believe water is blue. Have they never seen a picture of the earth from space? Did they then think it was blue because it reflected the sky?
Posted by: Steve P. | May 28, 2008 5:26 PM
Steve P.: I think people believe that the earth from space is so far outside their experience that radically different things must happen there--for example, if you hold a book at chest height in space and release it, it stays there, which is not known to happen under normal conditions on Earth. Also, most people outside seaside areas will only see large volumes of water in the context of swimming pools, the insides of which are usually painted a light greenish-blue in order to make the water look more inviting. These pool users see the color of the pool walls and mentally "subtract" it from the water's color, and decide it's as clear as the Sprite they're drinking after they swim.
Posted by: Adam | June 5, 2008 2:43 AM
Dear,
According to me the water appear blue is because of the scattering of light.The water that we have seen in photos are mostly in the open space and hence the scattering is prominant. Please see the pure water in dark or take its absorption maxima on Spectroscopy
Posted by: pushkar | June 6, 2008 10:51 AM
The sky is blue because the sun is blue. All that scattering stuff is the how not the why -- no blue light to scatter, no blue sky. Though the weakness of human vision in the purple definitely counts as why, too, thanks for that.
Posted by: Ed | June 16, 2008 2:47 AM