What does the sky appear blue, and what is it's real color?
87869
The sky is technically clear - this can be seen on any clear night. The blue color of the sky is due to Rayleigh scattering. As light moves through the atmosphere, most of the longer wavelengths pass straight through. Little of the red, orange and yellow light is affected by the air.\n\nHowever, much of the shorter wavelength light is absorbed by the gas molecules. The absorbed blue light is then radiated in different directions. It gets scattered all around the sky. Whichever direction you look, some of this scattered blue light reaches you. Since you see the blue light from everywhere overhead, the sky looks blue.
271347
The blue color of the sky is due to Rayleigh scattering. As light moves through the atmosphere, most of the longer wavelengths pass straight through. Little of the red, orange and yellow light is affected by the air. \n\nHowever, much of the shorter wavelength light is absorbed by the gas molecules. The absorbed blue light is then radiated in different directions. It gets scattered all around the sky. Whichever direction you look, some of this scattered blue light reaches you. Since you see the blue light from everywhere overhead, the sky looks blue. \nAs you look closer to the horizon, the sky appears much paler in color. To reach you, the scattered blue light must pass through more air. Some of it gets scattered away again in other directions. Less blue light reaches your eyes. The color of the sky near the horizon appears paler or white.
476620
The sky is blue because it would be ugly red....JK. The sky is blue because of all the mixes of gases in the atmosphere.  ;)
213854
1. Why the sky is blue.\nWhen light passes through a medium with molecules much smaller than the wavelength, it is scattered. You can understand it so: the light begins by going as a beam "forward". It gets absorbed for a moment by a molecule and then emitted again in whatever direction. This effect is more effective when the wavelength is shorter. Blue light has a wavelength ~2 times shorter than red light and gets scattered 16 times as effectively. So the beam coming directly from the sun is deprived of blue =>thus it is yellow (or red if it is sunset and it has passed a thick layer of atmosphere (geometry)). From all other directions we see the light that was going towards other points on the Earth. The yellows and reds went on and the blue was sent in other directions, including towards us.\n\n2. Why the grass is green.\nGreen plants use light to make food. The light is absorbed by chlorophyll (two types of it, too and a bit different, but no matter). Chlorophyll absorbs violet, blue, orange and red light. What we see is what was not absorbed, but reflected. If you take the aforementioned colours out of the white light spectrum, you get a mixtureof green and yellow. And green is the colour our eyes see best. Thus - green grass.\n\nI hope I've been clear
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)
838471
It is easy to see that the sky is blue. Have you ever wondered why? A lot of other smart people have, too. And it took a long time to figure it out!\n\nThe light from the Sun looks white. But it is really made up of all the colors of the rainbow. \nA prism is a specially shaped crystal. When white light shines through a prism, the light is separated into all its colors. \n\nIf you visited The Land of the Magic Windows, you learned that the light you see is just one tiny bit of all the kinds of light energy beaming around the Universe--and around you! \n\nLike energy passing through the ocean, light energy travels in waves, too. Some light travels in short, "choppy" waves. Other light travels in long, lazy waves. Blue light waves are shorter than red light waves. \nAll light travels in a straight line unless something gets in the way to--\n\n\nreflect it (like a mirror) \n\nbend it (like a prism) \n\nor scatter it (like molecules of the gases in the atmosphere) \n\nSunlight reaches Earth's atmosphere and is scattered in all directions by all the gases and particles in the air. Blue light is scattered in all directions by the tiny molecules of air in Earth's atmosphere. Blue is scattered more than other colors because it travels as shorter, smaller waves. This is why we see a blue sky most of the time.\nCloser to the horizon, the sky fades to a lighter blue or white. The sunlight reaching us from low in the sky has passed through even more air than the sunlight reaching us from overhead. As the sunlight has passed through all this air, the air molecules have scattered and rescattered the blue light many times in many directions. Also, the surface of Earth has reflected and scattered the light. All this scattering mixes the colors together again so we see more white and less blue.\n\nWhat Makes a Red Sunset?\n\nAs the Sun gets lower in the sky, its light is passing through more of the atmosphere to reach you. Even more of the blue light is scattered, allowing the reds and yellows to pass straight through to your eyes\nSometimes the whole western sky seems to glow. The sky appears red because larger particles of dust, pollution, and water vapor in the atmosphere reflect and scatter more of the reds and yellows\n\nWhy Does Scattering Matter?\n\nHow much of the Sun's light gets bounced around in Earth's atmosphere and how much gets reflected back into space? How much light gets soaked up by land and water, asphalt freeways and sunburned surfers? How much light do water and clouds reflect back into space? And why do we care? \nSunlight carries the energy that heats Earth and powers all life on Earth. Our climate is affected by how sunlight is scattered by forests, deserts, snow- and ice-covered surfaces, different types of clouds, smoke from forest fires, and other pollutants in the air. \n\nMISR (for Multi-angle Imaging SpectroRadiometer) is one of five instruments onboard the Terra satellite. MISR has nine separate cameras that take pictures of Earth's atmosphere and surface from different angles as the Terra satellite passes over a region during its orbit
213070
Ocean's colour seems to be blue because it gets the sky's reflection over it.\nAnd the colour of the sky is blue bcuz of the various gases present in the atmosphere\nMainly nitogen and oxygen.
1015359
using simple physics\n\nThe blue color of the sky is due to Rayleigh scattering. As light moves through the atmosphere, most of the longer wavelengths pass straight through. Little of the red, orange and yellow light is affected by the air.\n\nthe grass is green because the other colors are absorbed and only green is reflected. Grass and most other plants are green because they contain a pigment known as chlorophyll.\n\nSun isn't really yellow. The color yellow is a purely human interpretation of a collection of radiation that hits the retinae of our eyes and gets processed by our visual cortex.
661379
The blue sky is caused by the light from the sun travelling through the upper atmosphere and passing through particles, which scatter the blue part of the spectrum quite well. The other parts of the spectrum are still scattered, but less efficiently. So you see a 'blue' sky because that's the part of the light spectrum being directed towards you.\nYou could look up the Rayleigh Effect for more indepth info.
517525
The sky is blue because light reflects off oxygen molecules in the atmosphere, which makes it blue.\n\nGrass is green because of the chlorophyll in the grass.\n\nWater is wet because our nervous system detects it as such.
249388
One of the most common questions on YA!\n\nA clear cloudless day-time sky is blue because molecules in the air scatter blue light from the sun more than they scatter red light.  When we look towards the sun at sunset, we see red and orange colours because the blue light has been scattered out and away from the line of sight.\n\nSee the link below for full details.
71027
first of all, to Paranoid Princess:\n\nwhoa, whoa WHOA.  just a minute.  the sky is not blue because there's liquid oxygen in the upper atmosphere.  that's just retarded and you shouldn't go presenting bizzare mis-truths as fact when they *aren't* fact.\n\nhere is a profile of temperatures at various altitudes:\nhttp://www.windows.ucar.edu/tour/link=/earth/images/profile_jpg_image.html\nas you can clearly see the lowest temperature is about -100C.  oxygen liquefies at -182C at normal pressures (reference: http://www.ucc.ie/ucc/depts/chem/dolchem/html/elem/elem008.html ), and even lower temperatures at the low pressures in the upper atmosphere.  PLEASE don't present some bizarre fiction as truth to someone who isn't well-informed enough to know that you're simply fabricating nonsense from thin air.  if you have simply been misled by someone else, at least try to do a marginal amount of research before answering a question on something you don't know much about.\n\nthat said, to the original asker:\n\nthe sky is blue because of a phenomenon called "rayleigh scattering", which occurs because the molecules of air (mostly N2 and O2) happen to be the right size to scatter blue light in all directions.  some of this blue light reaches your eye after being re-scattered again by a second molecule, sometimes all the way across the sky.  \n\nthis is also why the sky turns red at sunset - at low angles, the sunlight has to travel a longer distance through the atmosphere, and by the time it reaches your eye, a lot of the blue light has already been scattered away, leaving yellow orange and red.  (i have yet to hear any explanation of why the sky doesn't turn green between daytime and sunset, though.  still tryin' to figure that one out.)\n\nanyway here are some home/school experiments designed to illustrate rayleigh scattering:\nhttp://www.physics.brown.edu/physics/demopages/Demo/optics/demo/6f4010.htm\nhttp://www.chaosscience.org.uk/dem/public_html/article.php?story=20050222224622239\nhttp://teachers.web.cern.ch/teachers/archiv/HST2002/smallexp/krug/Rayleigh.htm\nhttp://bulldog2.redlands.edu/facultyfolder/deweerd/research/scattering-AJP.pdf\nhttp://www.ktca.org/newtons/9/sky.html\n\nalso, a nice page illustrating rayleigh scattering:\nhttp://hyperphysics.phy-astr.gsu.edu/hbase/atmos/blusky.html\nand a slightly more advanced version:\nhttp://world.std.com/~mmcirvin/bluesky.html
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The sky appears blue due to the scattering of sunlight by dust particles in the air.\n\nSunlight is comprised of light in different wavelengths and can easily be split with a prism.  The dust particles in the air are of the right size that they scatter blue light preferentially.  As a result, we see the sky blue.\n\nThe sky is black at night simply because there isn't any blue light to be scattered.\n\nIncidentally, moonlight is yellow because that is the generally reflected colour off the moon's surface.  It is reflected light strongly in the yellow waveband. The yellow light is not affected by atmospheric scattering.
617565
The water particles,mixed in the air ( sky ), are responsible for this.The sunlight is refracted by those water molecules and thus we see the colour of the sky as blue.As you may remember,in the rainbow colours,Blue comes just after Violet and Indigo which are not that prominent as Blue. \nThus we see the sky blue.
916826
"The blue color of the sky is due to Rayleigh scattering. As light moves through the atmosphere, most of the longer wavelengths pass straight through. Little of the red, orange and yellow light is affected by the air.\n\nHowever, much of the shorter wavelength light is absorbed by the gas molecules. The absorbed blue light is then radiated in different directions. It gets scattered all around the sky. Whichever direction you look, some of this scattered blue light reaches you. Since you see the blue light from everywhere overhead, the sky looks blue. "
159646
The blueness of the sky is caused by sunlight scattering off particles in the atmosphere.  The intesity of the scattering is a strong function of the wavelength of light, so the blue light (one end of the spectrum) is observed more than red (the other end).
124021
A clear cloudless day-time sky is blue because molecules in the air scatter blue light from the sun more than they scatter red light.  When we look towards the sun at sunset, we see red and orange colours because the blue light has been scattered out and away from the line of sight.