Why are rainbows round?
The rainbow that appears after a rain shower forms an arc instead of a complete circle. This is because there are no raindrops below the level of the horizon to scatter sunlight back to the viewer. When the sun is high in the sky, no rainbow can be seen. Rainbows typically occur after a brief thundershower when the sun is low in the sky. They can also occur in the mist of a waterfall and in the spray from a garden hose. Sunlight is composed of all the colors that appear in a rainbow: violet, blue, green, yellow, orange, and red. Each of these colors has a different range of wavelengths. As a result, each color is refracted (bent) at a different angle when sunlight enters a raindrop. Red is bent the least, violet the most. When the colors strike the far side of a raindrop, they are reflected. As they leave the raindrop and enter the air again, they are again refracted. The following are the kinds of Rainbows: In the primary rainbow, which is the type most often seen, red forms the outer
