Rainbows: Beauty and Brains

While reading through the text book, I found a brief paragraph on rainbows on page 352. Although most of us enjoy looking at them, we sometimes fail to realize the complex science involved in creating a rainbow. 

http://wiki.answers.com/Q/Why_does_a_rainbow_appear_bent_or_arched_in_a_semicircle_in_the_sky

http://eo.ucar.edu/rainbows/

http://www.popsci.com/scitech/article/2003-04/why-are-rainbows-shaped-arch

The suns light is made up of the several colors of the rainbow; red, orange, yellow, green, blue, indigo and violet. When all these colors are combined they look white, like the light we always see. Each color has a different wave length which causes them to separate when light comes in contact with a prism.

After it rains, the air is filled with water droplets in the air. These droplets act as tiny prisms, breaking the sunlight into a spectrum. When the lights hits the water, each color goes in a different direction causing each one to be visible in the order of a rainbow

The sun also has to be at the right angle. The sun is always behind you when you face a rainbow. The center of the circular arc of the rainbow is in the direction opposite to that of the sun. And the rain is in the direction of the rainbow.

Rays of a rainbow bend twice. As they enter the drops, the rays are bent, then they reflect off the back of the drops and bend again as they exit out the front of the drops.The rainbow is circular because when a raindrop bends light, the light exits the raindrop at a 40-42 degree angle away from the angle it entered the raindrop. Each color bends at a different angel causing them to separate.

Light can also enter a droplet, be reflected off the back of the droplet, only to be reflected of the front, and then off the back again before leaving. It is bent at each phase in this process, and a second rainbow can appear above the first one. In a double rainbow, the second rainbow will appear where it does because the light will be cumulatively bent some 50 to 53 degrees. So it will be bent farther from the first rainbow making it appear under it.

Rainbows don't have "ends" but are full circled, but we can't see this because the horizon of the earth is in the way. If the sun is very low in the sky, either just before sunset or just after sunrise, we can see a half circle. The higher the sun is in the sky, the less we see of the rainbow. 

HERES A GUY THAT REALLY APPRECIATES A DOUBLE RAINBOW!!