A rainbow is sunlight spread out into an arc of colours and seen by your eyes when the sun shines through water droplets.
White light is actually a combination of all the colors normally
displayed in a rainbow. When this white light is refracted through a
glass or through a drop of water it is broken up and the various
component colors show in regular bands. The rainbow itself is caused
through the refraction of the white light of the sun's rays through
drops of rain.Although very, very few people may have seen them,
rainbows are also formed by moonlight, though the colors are faint and
scarcely distinguishable.
Most
people know the colors of the rainbow - red, orange, yellow, green,
blue, indigo and violet BUT few have been fortunate to see the rarer
manifestations of one of Nature's most beautiful phenomena.Some rainbows are all purple, all red, or even white. Some, instead of
arching into the sky, lie flat or stand vertically in glowing pillars.
And sometimes from an airplane, one can see a complete circle of
multicolored light.
1. Purple Rainbow
PURPLE
RAINBOWS are seen only before or at sunrise. This is a rare occurrence
sometimes formed when high clouds scatter the blue and violet light
which raindrops reflect back at the viewer.
2. Red Rainbows
RED
RAINBOWS are seen at sunset when the Sun is low in the sky. The shorter
wavelengths blue, green and yellow have been dispersed during their trip
through the atmosphere.
3. White Rainbows
WHITE
RAINBOWS appear in daylight or Moonlight but for different reasons.
During the day, the rays of sunlight may be reflected from very small
droplets of moisture that are so small the emerging bands of color
overlap creating white light. A White Rainbow seen by Moonlight is
actually not white at all but appears that way because the eye cannot
detect color in light as weak as the Moon is reflecting.
4. Double Rainbows
DOUBLE
RAINBOWS have colors that are mirror images. This is because the light
in the outer rainbow is reflected twice inside the raindrops emerging at
an angle that causes the colors to be reversed.
5. Straight Rainbow
STRAIGHT
RAINBOWS are usually seen over large expanses of water. Scientists
suggest that reflections from the water create a number of rainbows one
above the other with only the ends visible.
