Why do colors fade after prolonged exposure to the sun?
352506
Its not teh sun but a matter of both SUN and AIR because without air there is no medium for the light to travel thru, so technically the sun/air combination perform and chemical corrosion of the ink [since they are usually biodegradable] thus making your favortie 40 Licks t-shirts look like a homlees person has been wearing it for the past 25 years.
160687
Sky blue\n--------\n\nYou 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 more than 400 times so far here. \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.\n\nGrass Green\n-------------\n\nFrom the color of chlorophyll, the chemical that plants use to capture energy from sunlight. \n\nEarth Boring\n-------------\n\nIf the earth is boring, then what is not boring to you?
744212
take a dark colored cloth and a light colored cloth.expose them to heat or sunlight.u will see that dark colors get hot very quickly than light colored cloth.switch off the source and u will see that the heat is quickly lost by dark cloth than light cloth.
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
700772
Because the color of any object which does not emit light is really due to the effect of reflection, there are various ways in which color is "generated".\n\nThe color spectrum is Red, Orange, Yellow, Green, Blue, Indigo and Violet.  Because the light emitted by the Sun is most intense in the Yellow part of the spectrum, we see Yellow as the brightest "color".  Go in any direction away from Yellow and we see darker and darker colors. \n\nWe see the color of an object as the summation of the light that is reflected by that object.  When a piece of cloth or paper is wet, it absorbs water which fills in the spaces between the fibers.  Water reflects mostly in the blue spectrum, so that adds to the total light which is reflected by the object.  This added blue light makes the total light appear "darker" to us since it "drags" the spectrum of refelcted light away from Yellow.
503180
Darker colors absorb the sun's rays and heat is built up.  Lighter colors tend to reflect and they stay cooler.  That's why people tend to wear white or light colors in the summer and dark colors in the winter.
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.
764619
To start of with we must understand what light is. \n\nLight isnt just made up of 1 colour, it contains a number of different colours each of which has a different wavelength. Light is split up into the following colours with the first having the longest wavelenght and the last having the shortest. \n\nRed\nOrange\nYellow\nGreen\nBlue\nIndico\nViolet\n\nAn easy way to rememeber this is ROY G BIV (my year 12 geology teacher taught me that about 8 years ago)\n\nAs light moves through the atmosphere, most of the longer wavelengths are able to 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 in the atmosphere which is mainly nitrogen (78%) and oxygen (21%). The absorbed blue light is then scattered in all different directions. Since you see the blue light from everywhere overhead, the sky looks blue. \n\nOn Earth, the sun appears yellow. If you were out in space, or on the moon, the sun would look white. In space, there is no atmosphere to scatter the sun's light. On Earth, some of the shorter wavelength light (the blues and violets) are removed from the direct rays of the sun by scattering. The remaining colors together appear yellow. \n\nYou didnt ask about sunsets, but what the heck :)\n\nWhat happens during sunsets is that as the sun begins to go down, the light must travel farther through the atmosphere before it gets to you. More of the light is reflected and scattered. As less light reaches you directly, the sun appears less bright. The color of the sun itself appears to change, first to orange and then to red. This is because even more of the short wavelength blues and greens are now scattered. Only the longer wavelengths are left in the direct beam that reaches your eyes. \n\nThe second part of the your question is a lot easier. The sky is black simply  because of the lack of light from the sun going through the atmosphere. If there are no colours from the spectrum to get absorbed then the only thing that is left is the blackness of the sky.
87052
The orange and red tints that the Sun and Moon sometimes take on are caused by the particles in the Earth's atmosphere. \n\nWhen light (or more specifically, packets of light called photons) from an astronomical object passes through the Earth's atmosphere, it scatters off of particles in the latter. It turns out that these particles like to scatter blue light more than they do red light; so "bluer" photons (those with shorter wavelengths) tend to get scattered, and "redder" photons (those with longer wavelengths) pass through. So, astronomical objects look redder from Earth than they would from space, because the redder wavelengths from the objects penetrate the atmosphere better than the bluer ones. Incidentally, this is why the sky is blue: blue light from the Sun is scattered in all directions on its way to the Earth. \n\nBut how does this explain the occasional redness of the Moon or the Sun? Your son may have noticed that they always occur when the Sun or Moon is close to the horizon. If you think about it, sunlight or moonlight must travel through the maximum amount of atmosphere to get to your eyes when the Sun or Moon is on the horizon (remember that that atmosphere is a sphere around the Earth). So, you expect *more* blue light to be scattered from Sunlight or Moonlight when the Sun or Moon is on the horizon than when it is, say, overhead; this makes the object look redder. In other words, the Sun or Moon tends to look orange or red when it is rising or setting because that's the time when the light has to travel through the most atmosphere to get to you. The effect is exacerbated when there are thin clouds in front or behind the Sun or Moon: the clouds themselves often glow bright pink as well, because they are so good at scattering blue light
523333
Here's a good rule of thumb:  if prolonged exposure doesn't give you a sunburn, the UV light probably isn't going to damage your eyes.
1096572
I used to get this a lot when I used to regularly stay awake for 70+ hours in a stretch (I had problems and didn't sleep much).  Basically the way that the eyes work involves two main pigments (often called visual yellow and visual purple) which are photosensative (like camera film) and they constantly renew themselves, if you have not slept enough sometimes the production of these visual pigments slows down a bit leading to shapes and specks in th peripheral vision.  \nHave a great day and get more sleep!
389534
it is because of tyndall effect as the blue clour as a longer wave length in the spectrum of colours it gets scaterd more in the sky \n \n     \nmxwltan\n6 minutes ago\n\n\n \n The Earth's sky is blue because the air molecules (largely nitrogen\nand oxygen) are much smaller than the wavelength of light. When light\nencounters particles much smaller than its wavelength, the scattered\nintensity is inversely proportional to the 4'th power of the\nwavelength. This is called "Rayleigh scattering," and it means that\nhalf the wavelength is scattered with 2**4 = 16 times more intensity.\nThat's why the sky appears blue: the blue light is scattered some 16\ntimes more strongly than the red light. Rayleigh scattering is also\nthe reason why the setting Sun appears red: the blue light has been\nscattered away from the direct sunlight.\n\nThus, if the atmosphere of another planet is composed of a transparent\ngas or gases whose molecules are much smaller than the wavelength of\nlight, we would, in general, also expect the sky on that planet to\nhave a blue color.\n\nIf you want another color of the sky, you need bigger particles in the\nair. You need something bigger than molecules in the air---dust.\n\nDust particles can be many times larger than air molecules but still\nsmall enough to not fall out to the ground. If the dust particles are\nmuch larger than the wavelength of light, the scattered light will be\nneutral in color (i.e., white or gray)---this also happens in clouds\nhere on Earth, which consist of water droplets. If the dust particles\nare of approximately the same size as the wavelength of light, the\nsituation gets complex, and all sorts of interesting scattering\nphenomena may happen. This happens here on Earth from time to time,\nparticularly in desert areas, where the sky may appear white, brown,\nor some other color. Dust is also responsible for the pinkish sky on\nMars, as seen in the photographs returned from the Viking landers.\n\nIf the atmosphere contains lots of dust, the direct light from the Sun\nor Moon may occasionally get some quite unusual color. Sometimes,\ngreen and blue moons have been reported. These phenomena are quite\nrare though---they happen only "once in a blue moon...." :) The dust\nresponsible for these unusual color phenomena is most often volcanic\nin origin. When El Chicon erupted in 1982, this caused unusually\nstrongly colored sunsets in equatorial areas for more than one year.\nThe much bigger volcanic explosion at Krakatoa, some 110 years ago,\ncaused green and blue moons worldwide for a few years.\n\nOne possible exception to the above discussion is if the clouds on the\nplanet are composed of a strongly colored chemical. This might occur\non Jupiter, where the clouds are thought to contain sulfur, phosphorus,\nand/or various organic chemicals.\n\nIt's also worth pointing out that the light of the planet's primary is\nquite insignificant. Our eyes are highly adaptable to the dominating\nillumination and perceive it as "white," within a quite wide range of\npossible colors. During daytime, we perceive the light from the Sun\n(6000 K) as white, and at night we perceive the light from our\nincandescent lamps (2800 K, like a late, cool M star) as white. Only\nif we put these two lights side-by-side, at comparable intensities,\nwill we perceive a clear color difference.\n\nIf the Sun was a hot star (say of spectral type B), it's likely we\nstill would perceive its light as "white" and the sky's color as blue
67486
Colors in the sky occur when dust particles and debris are struck by sunlight rays and that alters their path.\n\nhttp://www.mountainnature.com/Climate/SkyColours.htm
782431
Why SUN appears red in dawn? (and dusk)\n\nThis is the time when the sun's light travels through most atmosphere to reach us. The small particles of dust scatter some of the light and most of the light scattered is blue light. As the blue light gets scattered out of the original white light the light that reaches us has a bredominance of red light and so the sun appears red.\n\nThis also explains why the sky appears blue during the day as we see much of this scattered light coming at us from all directions. It also explains why when we see the sun through smoke it appears very red as well and why we see great sunsets after days with a great deal of haze or after some event such as a huge volcanic eruption somewhere on the earth gives us a long sequence of beautiful sunsets (and sunrises) as the eruption of Mt Pinatubo in the Philipines did in the 1980s
648346
its something in the genes.\nwhen the skin is bombarded with UV rays it has a reaction in the cells that cause it to create the pigment that makes you tan and prevents burning, this is all as a protection. but with some people the cells aren't as sensitive as they should be, which causes people with fair skin that burn very easily or people who don't seem to tan at all.\nIn the case of albinos, they have no pigments whatsoever and can burn quite easily if exposed to the sun for too long, they do stand a higher chance of getting cancer if they have repeated exposure to the sun. this is why albino's choose to live in a temperate climates, like England, where it's not always sunny every day and some go out only at night in the summer, the invention of the 24 hour supermarket was a blessing for them. Albino's though are quite rare.
233432
The color depends mainly on three factors:\n\n1: The material. Different materials burn with different color\n\n2: Temperature. A material subjected to different temperatures will glow with different colors. (The speed through the atmosphere will give different temperatures)\n\n3: Distance to object. Colors are spread because of the air in the atmosphere, just look at the Sun, red when the light travels far through the air and yellow/white when the distance is shorter.
870607
it's an area of high magnetic activity that keeps heat convection from occuring. Basically the magnetic forces cools the spot, making it darker in comparison to the rest of the surface of the sun. Sun spots also occurs in cycles of around 30 years, but nobody knows what causes is this...