How are rainbows formed/seen?
359455
A rainbow is produced when white light is split by differaction into light of different colours as it passes through raindrops. The colours that are produced are called spectrum. the colours in the spectrum are usually said to be red,orange,yellow,green,indigo and violet.
160214
They also occur as a circle, if you're in a plane (i was in a microlight) above mist/cloud it's the most spectacular sight, I looked down and there was a circular rainbow. It has to do with the fact that you're viewing it from one point, all the rainbow is relative to you.
1173045
You know how you see a rainbow when its really humid, or when it rains and there is sun? Thats what you saw, you saw a rainbow, but not a half rainbow, but rather a whole rainbow around the sun. A ring rainbow, this is due because of the high humidity that is in the air, its the same as a rainbow, just around the sun.
566742
As spijk says, the rainbow is formed by the refraction (bending) of light as it passes trhough rain drops. But the reason an observer sees the rainbow as an "arc" is that the sunlight must be refracted at a certain constant critical angle between the arrival of the light ray and the path back to the observers eye for the colors to be seen. This angle occurs over an arc in relation to the observer.  Here's why:\n\n   There are three conditions necessary for the rainbow to be visible:\n\n  First, there has to be water droplets in the air (These   droplets may or may not be falling to the ground as rain), and -\n\nSecond: -  the sun must be behind the observer while looking at the rainbow - and -\n\nThird: - the light rays that become visible as the rainbow must pass through the raindrops at the critical angle.\n\nIf you draw these conditions out in three dimensions, it is apparent that the necessary conditions only prevail to the observer as an arc.  \n\nBy the way, the rainbow is not always a semi-circle! If you're airborne, above the droplets with the sun high in the sky, you will see the rainbow as a circle!\n\nI fly my own plane and have seen this condition on several occasions, and even took a picture of it once!\n\nNow you can understand why seeing rainbows is relatively rare - the conditions for their appearance are not very common, mainly because you have to have water droplets in the air at the same time that the sun is not blocked by clouds!  That's why the most common time to see a rainbow is after a relatively small afternoon thunderstorm cell passes your position (usally passing from west to east), dropping rain beneath it as it passes and then leaving clear sky behind allowing the sun rays to strike the raindrops.\n\nGo to the website below for diagrams on how the rainbow works! A picture is worth a thousand words, especially a picture of a rainbow! :-)\n\neo.ucar.edu/rainbows \n\nBy the way, good question!  You have a keen mind, keep asking questions!  After reading and doing your homework, its the best way to learn!\n\nHope this answer  helps.\n\nCharlieQ
125458
Well I think they appear as lines; fat, multicolored, curved lines.  But they aren't really "there" where we see them.  That is, other people, say a mile away from you, will see the rainbow shifted from where you see it, and that's because the rainbow's apparent direction is relative to the sun's rays that are near you.  But is this the answer to your question?  Are you asking why they're not thin? straight?  Give us something, Bea.
222325
The rainbow is a prism that occurs when light travels through water or something that can bend the light to creat the colors that we call the rainbow.
199551
well nwhen white light goes through a prisdim, it breaks and turns into the colors of the rainbow. so when white light goes through the atmosphere, which acts like a prism, it breaks and we mostly see the blue
1102653
The sunlight spectrum is made of all colors of the rainbow, and seen as light because all the colors are present at the same time. \n\nWater magnifies the visibility of this light and we are able to see the colors of light distinct and separated into the actual colors of sunlight.
393409
They don't have dark sides, because rainbows are light by their own nature, but they do have a "hidden half"; rainbows are actually giant circles that have their bottom half obscured by the horizon.
661147
This is EARTH SCIENCE, not religion...:(\n\nA rainbow appears from refraction (not reflection) of sunlight through water in the atmosphere.  The circumstances for us seeing them usually happen around sunrise and sunset, since the refraction occurs in a circle around the source of light (the sun), only half of which is visible since the other half would be on the ground.  When the sun is higher in the sky, that same circular angle around the light source puts the whole thing on the same plane as the ground.  \nIt's simple refraction of light, simple physics -- doesn't have anything to do with god.
786396
hi, try this link .. its a nice one ..\n\nhttp://eo.ucar.edu/rainbows/
427036
Rainbows are caused by sunlight reflecting off and refracting through raindrops. There is a very specific angle that each different wavelength of light will take so all parts of the rainbow of that color are always seen at exactly that angle away from the Sun, about 42 degrees for visible light. In math, the collection of all points at a certain distance from a point is a circle, so rainbows are seen as a circle around the sun.
280331
What makes the bow?\nA question like this calls for a proper physical answer. We will discuss the formation of a rainbow by raindrops. It is a problem in optics that was first clearly discussed by Rene Descartes in 1637. An interesting historical account of this is to be found in Carl Boyer's book, The Rainbow From Myth to Mathematics. Descartes simplified the study of the rainbow by reducing it to a study of one water droplet and how it interacts with light falling upon it. \nHe writes:"Considering that this bow appears not only in the sky, but also in the air near us, whenever there are drops of water illuminated by the sun, as we can see in certain fountains, I readily decided that it arose only from the way in which the rays of light act on these drops and pass from them to our eyes. Further, knowing that the drops are round, as has been formerly proved, and seeing that whether they are larger or smaller, the appearance of the bow is not changed in any way, I had the idea of making a very large one, so that I could examine it better. \n\nDescarte describes how he held up a large sphere in the sunlight and looked at the sunlight reflected in it. He wrote "I found that if the sunlight came, for example, from the part of the sky which is marked AFZ  \n\nand my eye was at the point E, when I put the globe in position BCD, its part D appeared all red, and much more brilliant than the rest of it; and that whether I approached it or receded from it, or put it on my right or my left, or even turned it round about my head, provided that the line DE always made an angle of about forty-two degrees with the line EM, which we are to think of as drawn from the center of the sun to the eye, the part D appeared always similarly red; but that as soon as I made this angle DEM even a little larger, the red color disappeared; and if I made the angle a little smaller, the color did not disappear all at once, but divided itself first as if into two parts, less brilliant, and in which I could see yellow, blue, and other colors ... When I examined more particularly, in the globe BCD, what it was which made the part D appear red, I found that it was the rays of the sun which, coming from A to B, bend on entering the water at the point B, and to pass to C, where they are reflected to D, and bending there again as they pass out of the water, proceed to the point ". \n\nThis quotation illustrates how the shape of the rainbow is explained. To simplify the analysis, consider the path of a ray of monochromatic light through a single spherical raindrop. Imagine how light is refracted as it enters the raindrop, then how it is reflected by the internal, curved, mirror-like surface of the raindrop, and finally how it is refracted as it emerges from the drop. If we then apply the results for a single raindrop to a whole collection of raindrops in the sky, we can visualize the shape of the bow. \n\nThe traditional diagram to illustrate this is shown here as adapted from Humphreys, Physics of the Air.  It represents the path of one light ray incident on a water droplet from the direction SA. As the light beam enters the surface of the drop at A, it is bent (refracted) a little and strikes the inside wall of the drop at B, where it is reflected back to C. As it emerges from the drop it is refracted (bent) again into the direction CE. The angle D represents a measure of the deviation of the emergent ray from its original direction. Descartes calculated this deviation for a ray of red light to be about 180 - 42 or 138 degrees. \n\nThe ray drawn here is significant because it represents the ray that has the smallest angle of deviation of all the rays incident upon the raindrop. It is called the Descarte or rainbow ray and much of the sunlight as it is refracted and reflected through the raindrop is focused along this ray. Thus the reflected light is diffuse and weaker except near the direction of this rainbow ray. It is this concentration of ray
77085
Because it is refracting light that is coming from all around. When you see a rainbow produced by a prism it looks straight but if you were able to enlarge it enough it would be round.
655891
It doesn't matter if the rainbow appears around the sun or on the ground after a rainshower. The two rainbows are called primary and secondary bows. There are two because the sunlight is relected off the inside of a water droplet twice instead of once; once would result in only one rainbow. This all depends on the angle in which the sunlight enters the water droplet.\nThe secondary bow is fainter and  the colors are reversed.
436348
A rainbow is seen when the Sun is behind you and water is in the air in front of you. You can make one with a water hose or maybe see one in the air with rain in the area. Natural rainbows appear very large and several miles away. The top is all you can see because the ground in front of you blocks the lower portion of the rainbow. However, when seen from an airplane, rainbows are complete circles.
55008
Thats a simple science question.\nRainbows almost always appear during or right after a rainstorm. The water vapor in the air forms to act as a prism. With the right angles of sunlight in relation to the water vapor, the "prism" breaks the "white" or "ultraviolet" light up into it's true colors which are red, orange, yellow, blue violet and green. I always use to remember the primary colors by using the accronym, "roybug" changing the "u" to a "v" for the violet.