why is rainbow seen after heavy rainfall

Their colours here is more to just raindrops and colours. Light travels in waves depending on how big or small the waves are. It determines the color; for example, short wave-lights appear blue and long wave-lights appear red. Sunlight is made up of many wavelengths so that makes us see the colors of the rainbow.When the light enters the water, it bends causing its shape. Different colors of light have different frequencies, which causes them to travel at different speeds when they move through matter. A double rainbow forms if sunlight is passing through a thin stratum of clouds and a stratum of rains simultaneously then you can get two rainbows at a time. Some rainbows form as an arc or a semi circle and that is because rainbows are only partial part of a circle around the shadow of your head on which rainbows are seen. You can mostly only see circled rainbow from above like in an aircraft. When the water drops get very small the wave like nature of light starts to dominate which will wash out the colors in a rainbow until the drops are too small and a rainbow will not been seen at all. So a complete circular rainbow seen from an aircraft is going to look whiter than colored, with the shadow of the aircraft seen in the center.