What chemical reactions cause the sky to appear blue?
363326
not chemical reations\n\nonly reflection...
367501
"The red hues of the sky at sunset and sunrise are caused by the Rayleigh scattering, of blue light, by statistical fluctuations in the density of Earth's atmosphere."\nhttp://en.wikipedia.org/wiki/Sunset\n\n... which is...\n\n"Rayleigh scattering (named after Lord Rayleigh) is the scattering of light, or other electromagnetic radiation, by particles much smaller than the wavelength of the light."\nhttp://en.wikipedia.org/wiki/Rayleigh_scattering\n\nCheers!
86349
Blue is the color that is reflected from the atmosphere--alll over colors are absorbed...Light is divided into the colors of the spectrum and each color has it's own specific wavelength.....so the wavelength for "blue light" is reflected and not absorbed and that is why you see a blue sky.
38249
Actually there is no chemistry. Its all about physics - scattering of light.\n\nLight as you know is made up of lots of colors (seven colors visible in the rainbow actually consists of millions of colors). The color depends on the wavelenth of light. Light from the sun is white meaning it has all colors (wavelengths) equally.  \nThere is a principle in physics called Raleigh scattering. Short wavelenths(blue/violet) are absorbed and scattered by the atmosphere and with longer wavelenghts (red) are not absorbed/scattered. As blue light is scattered by the atmosphere it looks blue. \n\nAt twilight, the sky looks red/pink. This is because, the sun's light dosn't get chance of scattering. As red light is least absorbed, that is the light that comes directly to us.
80014
The nitrogen and the oxygen molecules in the air have the right dimensions to scatter blue light, but other colors pass through with little problem. So this causes the sky to look blue. \n\n(whitish sunlight)-(blue light scattered)= (yellowish sunlight)\n\nAs the sun sets (or rises), the sunlight passes through more air, and more blue light gets scatted, so the sunlight looks closer to orange or red\n\n(whitish sunlight)-(even more blue light scattered)=(red or orange sunlight)
378185
Particles in the air refract the white light of the sun into the spectrum.  The sky is blue because blue gets through the easiest.
860942
When sunlight hits the ocean it is scattered by the water molecules that make up the ocean. Sunlight is made up of all of the colors of the rainbow (red through violet). Water molecules scatter blue light the most. This makes the ocean look blue.\n\nThe reflection of the sky is a common misconception.  Algae and plankton also add color to the ocean as well.
24151
Everyone else is wrong. This has nothing to do with water. The sky is blue because as the light waves pass trhough the air they collide with molecules, effectively scattering the blue wavelenghts of light. This is demonstated by the fact that the sky at lower angles appears more blue, because there is more air that the light must travel through.
494735
"The sky is blue partly because air scatters short-wavelength light in preference to longer wavelengths. Where the sunlight is nearly tangent to the Earth's surface, the light's path through the atmosphere is so long that much of the blue and even yellow light is scattered out, leaving the sun rays and the clouds it illuminates red, at sunrise and sunset."
227364
You must realize that this has been asked over 500 times here. Surely when you asked this question you were notified. Why didn't you look at some of those previous questions and answers? I probably have answered this 50 times myself. I have some very careful detailed answers here to that question, if you just look. \n\nIt is called Rayleigh-Tyndall scattering, caused by the small size of the nitrogen and oxygen molecules in the air that scatter the blue out of the sunlight, leaving it more yellowish than it would be otherwise. At sunset, the reddish color is absorbed by the ozone overhead, creating a deep blue. \n\nIf you want more details, look it up.
66724
Rayleight Scattering.\n\nThe blue color of the sky is caused by the scattering of sunlight off the molecules of the atmosphere. This scattering, called Rayleigh scattering, is more effective at short wavelengths (the blue end of the visible spectrum). Therefore the light scattered down to the earth at a large angle with respect to the direction of the sun's light is predominantly in the blue end of the spectrum.
1006435
Scattering of Light \nBy small particles and molecules in the atmosphere \n\nDifferent from reflection, where radiation is deflected in one direction, some particles and molecules found in the atmosphere have the ability to scatter solar radiation in all directions. The particles/molecules which scatter light are called scatterers and can also include particulates made by human industry. \n\nSelective scattering (or Rayleigh scattering) occurs when certain particles are more effective at scattering a particular wavelength of light. Air molecules, like oxygen and nitrogen for example, are small in size and thus more effective at scattering shorter wavelengths of light (blue and violet). The selective scattering by air molecules is responsible for producing our blue skies on a clear sunny day. \n\nAnother type of scattering (called Mie Scattering) is responsible for the white appearance of clouds. Cloud droplets with a diameter of 20 micrometers or so are large enough to scatter all visible wavelengths more or less equally. This means that almost all of the light which enters clouds will be scattered. Because all wavelengths are scattered, clouds appear to be white. \n\nWhen clouds become very deep, less and less of the incoming solar radiation makes it through to the bottom of the cloud, which gives these clouds a darker appearance.
4645
because of water vapor (in the air...gives it a blueish hue.  not much to due with physics... maybe chemistry.
117362
One meaning to this is that you did not check the archive of previously asked questions before you posted your question about the sky's color. This has been asked and answered almost 400 times so far here (see link below). \n\nHowever, the reason the sky appears blue (at least most of the daylight hours) is that the atmosphere is mostly oxygen and nitrogen, which are just the right size molecules to scatter the blue light, but let the other colors pass unimpeded. \n\nSo when you take the blue away from the mostly white sunlight, you get sorta yellow sunlight. \n\nAs the sun sets, the sunlight passes through more air, and more blue is scattered away, leaving the sunlight even less blue, that is, more orange. \n\nAs the sun sets even farther, even more blue is scattered away, and the sunlight appears red.
1120862
There is a very, very detailed answer to this at the source below, but in a nutshell (and I quote): "The sky is blue because it is scattering blue light from the sun."\n\nAnd NO: The sky is not blue because of reflections from the oceans. As the source below says, if that were true, then the sky would be more blue out in the middle of the ocean and less blue when you are far inland. But it's equally blue at both locations.
387674
You can't see the stars during the day due to a process call Rayliegh scattering.\nBasically the sun radiates many visible colours of visible light even though it looks yellow. The blue light that the sun radiates is scattered by the atmosphere in all direction whilst other colours are unaffected. This gives the sky a blue appearance during the day. The blue sky is much brighter than the stars and thus we cannot see them.\nStrange fact: It is because the atmosphere is mostly nitrogen that the sky is blue, if the atmosphere was mostly oxygen it would be green.
12251
The scientific answer is very long which involves dipole scattering, charged particles vector potential and much more.  There is a simple answer though.  Think of how prism works.  When a light hits the prism, what happens?  The answer is the prism breaks the white light into visible color, red, orange, yellow, green, blue, and violet (these are the rainbow color).  Our atmosphere is filled with dust particles.  So when sun ray hits the particles in the atmosphere, it breaks the white light like the prism.  The color blue has the strongest wavelength out the rainbow colors.  Therefore, it effects more than the red and green wavelength, causing the surrounding air to appear blue.  But during the sunset, the sun light passes farther through the atmosphere causing them to deflect and decrease the blue color. So sunset appear to be red.