Monday, October 19, 2015

Electric and smiling rainbows

What is a rainbow? Rainbows are observed when rain is falling in one part of the sky while the sun is at the observers back. They can also be seen through sprays from waterfalls or sprinklers. When one sees a rainbow, they see sunlight that has been slowed and bent by a water droplet with violet light refracting the most and red light the least. While most of the light passes right through the water, some of the light strikes the back of the water droplet at such an angle that it is reflected inside of the drop. This angle is called the critical angle (48 degrees). The light that strikes the back of the drop at an angle which exceeds the critical angle is internally reflected toward our eyes. Since a raindrop isn’t a box with straight lines and drops vary in sides, the angle of light in different drops can vary. Each ray refracts from its own drop a slightly different angle. The light that exits the drop disperses into a spectrum of colors from red to violet. Since we see only a single color from each drop, it takes multitudes of raindrops (each refracting and reflecting light back to our eyes at slightly different angles) to produce the brilliant colors of a primary rainbow. Since everyone watching the rainbow exists in a slightly different location, every rainbow seen in person is a unique gift for the individual. Can a rainbow smile? Read moreRead more.

Beef and butterflies

Photo courtesy of Environmental Defense Fund Austin-area ranchers  and conservationists show beef and butterflies  can thrive...