MACON, Ga. — A rainbow forms when sunlight enters a raindrop. When this happens, sunlight bounces around the raindrop and changes speed and direction.
That's called refraction.
These changes also cause the light to change color.
The modified sunlight then reflects off the back of the raindrop and returns to the viewer, creating a visible rainbow. Many things have to occur for a rainbow to appear.
It has to be a few hours before sunrise or sunset. That's because the sun should be low enough for rain and sun to be present simultaneously.
The viewer must be opposite the sun. This allows the light to enter the raindrops, reflect, and exit toward you.
When the raindrops are larger, the light has more space to undergo these changes, making the color more visible.
There are times when light is reflected twice within the same raindrop. When this happens, a double rainbow forms.
A double rainbow is typically fainter, and the colors are reversed. The first rainbow has the colors of visible light: violet, indigo, blue, green, yellow, orange, and red. While, the second rainbow has its colors reversed (red on the inside, violet on the outside) due to the extra reflection.
