What is a rainbow?
It is an arch in the sky caused by the refraction. It is a combination of two
rainbows. Photographs of the rainbows are very
impressive of rainbow photographs.
Rainbows have some very excellent rays of colors. Sunlight looks
white but is actually red, orange, yellow, green, blue, indigo, and violet.
When sunlight hits the raindrops that is called a rainbow.
Refernces
http://www.weatherwizkids.com/weather-optical-illusions.htm