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.
The white light from the sun is a mixture of all colours of the rainbow. This was demonstrated by Isaac Newton, who used a prism to separate the different colours and so form a spectrum. The colours of light are distinguished by their different wavelengths. The visible part of the spectrum ranges from red light with a wavelength of about 720 nm, to violet with a wavelength of about 380 nm, with orange, yellow, green, blue and indigo between. The three different types of colour receptors in the retina of the human eye respond most strongly to red, green and blue wavelengths, giving us our colour vision.
It is a bit long to put it all here, but click on the link below!
Hope I could help!
2006-10-30 06:06:47
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answer #1
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answered by Anonymous
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The atmosphere is the mixture of gas molecules and other materials surrounding the earth. It is made mostly of the gases nitrogen (78%), and oxygen (21%). Argon gas and water (in the form of vapor, droplets and ice crystals) are the next most common things. There are also small amounts of other gases, plus many small solid particles, like dust, soot and ashes, pollen, and salt from the oceans.
The composition of the atmosphere varies, depending on your location, the weather, and many other things. There may be more water in the air after a rainstorm, or near the ocean. Volcanoes can put large amounts of dust particles high into the atmosphere. Pollution can add different gases or dust and soot.
The atmosphere is densest (thickest) at the bottom, near the Earth. It gradually thins out as you go higher and higher up. There is no sharp break between the atmosphere and space.
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.
However, 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.
2006-10-30 14:11:41
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answer #2
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answered by Fariy_God_Sistah 3
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The sky is blue as the oxygen molecules in the air refract the suns light as blue, while it absorbs the other colours. This is why the sky is blue and not red, green, yellow or so on...
2006-11-02 11:27:43
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answer #3
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answered by Anonymous
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The Sky is Blue because of.... *Drum Roll* Diffuse sky radiation !!what is it? Well it is solar radiation reaching the earth's surface after having been scattered from the direct solar beam by molecules or suspensoids in the atmosphere. Also called skylight, diffuse skylight, or sky radiation. Of the total light removed from the direct solar beam by scattering in the atmosphere (approximately 25 percent of the incident radiation), about two-thirds ultimately reaches the earth as diffuse sky radiation.
Scattering is the process by which small particles suspended in a medium of a different index of refraction redirect a portion of the incident radiation in all directions. In elastic scattering, no energy transformation results, only a change in the spatial distribution of the radiation. The science of optics usually uses the term to refer to the deflection of photons that occurs when they are absorbed and re-emitted by atoms or molecules.
2006-10-30 14:07:20
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answer #4
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answered by Miss LaStrange 5
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The light which leaves the sun and enters our atmosphere is considered white light. The gaseous chemical in our atmosphere filter the almost pure white light of the sun into what we have as not so pure white light on the surface of the Earth. In the process, the appearance of the filtered light tells us the sky is blue.
P.S. - The ocean is blue when you look at it because it's surface is reflecting the sky. Water is clear.
2006-10-30 14:07:10
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answer #5
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answered by Anonymous
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Everybody has told you what blue sky is but sky blue, which was your question is just a colour, the colour of the sky actually.
2006-10-30 14:18:41
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answer #6
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answered by Anonymous
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A clear 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.
The white light from the sun is a mixture of all colours of the rainbow. This was demonstrated by Isaac Newton, who used a prism to separate the different colours and so form a spectrum. The colours of light are distinguished by their different wavelengths. The visible part of the spectrum ranges from red light with a wavelength of about 720 nm, to violet with a wavelength of about 380 nm, with orange, yellow, green, blue and indigo between. The three different types of colour receptors in the retina of the human eye respond most strongly to red, green and blue wavelengths, giving us our colour vision.
Tyndall Effect
The first steps towards correctly explaining the colour of the sky were taken by John Tyndall in 1859. He discovered that when light passes through a clear fluid holding small particles in suspension, the shorter blue wavelengths are scattered more strongly than the red. This can be demonstrated by shining a beam of white light through a tank of water with a little milk or soap mixed in. From the side, the beam can be seen by the blue light it scatters; but the light seen directly from the end is reddened after it has passed through the tank. The scattered light can also be shown to be polarised using a filter of polarised light, just as the sky appears a deeper blue through polaroid sun glasses.
This is most correctly called the Tyndall effect, but it is more commonly known to physicists as Rayleigh scattering--after Lord Rayleigh, who studied it in more detail a few years later. He showed that the amount of light scattered is inversely proportional to the fourth power of wavelength for sufficiently small particles. It follows that blue light is scattered more than red light by a factor of (700/400)4 ~= 10.
Tyndall and Rayleigh thought that the blue colour of the sky must be due to small particles of dust and droplets of water vapour in the atmosphere. Even today, people sometimes incorrectly say that this is the case. Later scientists realised that if this were true, there would be more variation of sky colour with humidity or haze conditions than was actually observed, so they supposed correctly that the molecules of oxygen and nitrogen in the air are sufficient to account for the scattering. The case was finally settled by Einstein in 1911, who calculated the detailed formula for the scattering of light from molecules; and this was found to be in agreement with experiment. He was even able to use the calculation as a further verification of Avogadro's number when compared with observation. The molecules are able to scatter light because the electromagnetic field of the light waves induces electric dipole moments in the molecules.
2006-10-30 14:24:05
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answer #7
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answered by It's Me! 5
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Because blue light passes through Earth's atmosphere more easily than other colors...
2006-11-02 19:36:35
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answer #8
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answered by Anonymous
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Light bends through the moisture in the air and yields that color, just like in a prism. When the sunlight refract differently, such as sunset or through clouds, reds, orange and other colors develop.
2006-10-30 14:06:17
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answer #9
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answered by Anonymous
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because blue has the longest wave-lengths of light... and the sky is far away- thus it is blue
2006-10-30 14:02:50
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answer #10
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answered by rachel o 3
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