How is a Rainbow actually formed after its been raining?……..they e amazing!?
In a rain ‘bow’ (from an aeroplane it appears as a complete circle) we see many light rays that have been refracted then reflected and then refracted again inside spherical raindrops. Each ray leaves a droplet at a fixed angle to the ray going in so we can see only the rays from raindrops which lie at a fixed angle between us and the parallel rays from the sun behind us (i.e. we are really seeing light only from the raindrops lying on the surface of a ‘cone’ which has the pupil of our eye at its tip). Red light is refracted less than violet light, so a colour spectrum is created. Another outer rainbow (formed by light rays leaving the droplet at a slightly greater angle) appears fainter and has a reversed spectrum because light is reflected twice inside each raindrop instead of just once. The brightest rainbows are seen with the Sun quite low in a clear sky behind us but with heavy rain falling just in front of us. From the ground, you cannot see a rainbow at noon.
