What Is A Rainbow?
By Natalie Timinskas
9/27/12


How a Rainbow Works
A rainbow is a multi-colored arc in the sky. When a white light shines on a color like red, blue, or green it looks like red or blue, depending which color the white light shines on, it looks to us as that color. When the white light shines on something colored the object absorbs all the colors except its own color. The colors of the rainbow are red, blue, green, purple, orange, yellow, and violet. A rainbow is basically visible light.
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Figure 1, this diagram explains how a rainbow works.

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When does a Rainbow Form
Rainbows form when there’s sun and rain at once because the sun enters inside the rain drop then form some of the colors of the rainbow. The sun has to show if you want a rainbow to form. But it also has to be raining for there to be a rainbow or just water. Rainbows usually form in the morning or evening because the sun is low.
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Figure 3, Secondary rainbow-Reflected light leaves raindrop then sunlight enters the bottom of the raindrop then dispersed light is reflected lastly light reflected a second time.



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Figure 2, Primary rainbow- sunlight enters the top of the raindrop then reflects and leaves raindrop lastly dispersed light is reflected then.




Visible Light
Visible light is the very narrow range of wavelengths and frequencies in the electromagnetc spectrum that people can see. Visible light waves have between 400nm and 700nm. Sometimes some energy that reaches earth that came from the sun is visible light

Moonbows and Polar Lights
Polar lights are highly charged particles from the suns strike gases that’s in the atmosphere high above the poles then to create an amazing display of colored lights in the night sky. In the northern hemisphere this is known as aurora borealis. In the southern hemisphere it is known as aurora australis. In a rare occasion rain drops may catch a reflection of the moonlight to form a moonbow. The moonbow colors are faint.

Examples
The example that I am just about to tell you is perfectly safe so don’t be afraid to try it at home but ask your parent first. If you take a cup of water and shine a flashlight on the side of it you will see on the other side of is a rainbow but if you turn the light off there is no rainbow anymore. You could use a mirrow and shine a light on it then see where the rainbow went. This experiment is safe to but make sure that there’s a parent around to supervise you. If you shine a light on a prism on the other side you will see the rainbow but if you turn the light off there is no rainbow anymore. That happened because when a white light shines on water the water absorbs the white light then comes out of the water with the colors of the rainbow.


Glossary

Dispersed- To vanish or take away.

Electromagnetic- electric of a magnet.

Hemisphere- Parts of the globe.

Spectrum- It is like light waves or particles ordered by accordance.

Wavelengths- The distance, measured in the direction of the wave.





Citations

Kerrod, Robin. The Way Science Work. New York, NY: DK Publishing, 2002. Print.

Lewis, Peter. Light and Sound. Tucson, AZ : Brown Bear Books, c2010. Print.

Science Facts and Fun: What's in a Rainbow?.Shelburne Films, 1995 . Print.



"Rainbow." Britannica Elementary Encyclopedia. Encyclopædia Britannica Online School Edition.Encyclopædia Britannica, Inc., 2012. Web. 24 Sept. 2012. Web.


Watching the world wake up. "How a Rainbow Works”. Thursday, August 7, 2008. Web.