ROANOKE, Va. – Another popular questions students ask me during school visits is, “How do rainbows form?” The process might seem simple, but it’s actually pretty involved. Your back has to be facing the sun, and you most times will be looking at rain that’s moving away or toward you.
When the sun’s light enters the raindrop, that light gets bent (or refracted).
Once that light hits the other end of the drop, it is then reflected back toward you in the colors of the rainbow.
In some really special cases, you can get a fogbow. Because the water droplets are so tiny in fog, you don’t get the color of the rainbow. You just get a more pronounced “white-ish” color.