Sunday, April 3, 2011

Find a Rainbow Day


Find a Rainbow Day occurs each year on April 3. It is a day to hope for a rain shower that will produce a beautiful rainbow - maybe the first of the season! With the arrival of spring and the increasing occurrence of rain we have many more chances to see a rainbow.

Legends and Myths
Rainbows are one of nature's most beautiful spectacles. Throughout time, rainbows have been a symbol of hope, beauty, and luck, as well as fear, for some civilizations. We've all heard the story of the Leprechaun's hidden pot of gold at the end of the rainbow. Some say if a rainbow appears on the day a child is born it signifies good luck for the child. Some cultures believe the rainbow to be a bridge between heaven and earth. Iranian Muslims believe that if the prominent color of the rainbow is green it means abundance, red means war, and yellow brings death. The Zulus thought a rainbow was a giant supernatural serpent, while tribes in northeastern Siberia believe it is the tongue of the sun.

What Makes a Rainbow?
Rainbows are awe inspiring. But the science of rainbows is really quite simple. It has to do with optics. The fundamental principle which causes a rainbow is called refraction, or the bending of light. Light travels at different speeds through different mediums, so when light changes from one medium to another it "bends" or changes direction. When a beam of light goes from the air into a glass prism it changes direction. In addition to bending, the prism separates white light into it's component colors.

In order to see a rainbow, you must have three things: sunlight, air, and water. When you see a rainbow, the sun must be behind you while it is raining in front of you. The rays of the sun travel through the air and when the sunlight enters the raindrops they act as little prisms, the light then changes direction and separates into the various colors.

Primary Rainbow- A primary rainbow is the lowest, and normally the brightest rainbow. Sir Isaac Newton determined that the primary rainbow consists of seven colors: red, orange, yellow, green, blue, indigo, and violet with red at the top and violet at the bottom.

Double Rainbow- A double rainbow is when a second arc appears above and outside the primary arc. The second rainbow is caused by light reflecting twice inside the water droplets. The colors of the secondary arc are a reverse of the primary arc, so violet at the top and red at the bottom. The space between the two arcs is darkened.

For instructions on how to make a rainbow at home, go to OpticalIllusion.blogspot.com.
For a more detailed explanation about how rainbows are formed, go to How Stuff Works.

Rainbow Coloring Pages
On-line coloring page @ Scrap Coloring.com
Abstract Rainbow @ Doodle-Art-Alley.com
Spring Rainbow @ Lee Hansen.com
Basic Rainbow @ familycrafts.about.com
My Little Pony w/rainbow @ supercoloring.com

They Might Be Giants - Roy G. Biv

Image: Free Vector Graphics
Sources: Wikipedia  HowStuffWorks

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