NASA - National Aeronautics and Space Administration

Image above: Light comes to Earth from the sun

Light comes to Earth from the sun in waves. Some of the waves are longer. Some of the waves are shorter. We see the waves as the colors of the rainbow. Each color has a different wavelength. Red has the longest wavelength. Violet has the shortest wavelength. When all the waves are seen together, they make white light.

We think that white has no color, but that is not true. One way to see this is to shine white light through water. When white light shines through water, it makes a rainbow. The water breaks apart the color of white so we see all the colors of the rainbow. We call these colors the visible light spectrum.

Image above: The colors in the visible light spectrum

Our eyes have cones inside them to help us see the waves as color. Our eyes see the reflection of sunlight off of things around us. The color we see is the light reflected back to our eyes.

Image above: All other colors are absorbed, so we see only a RED apple

Beside our sun, light bulbs are another source of light.


 
To learn more about color and light, please visit The Scattering of Light.


Excerpted from http://imagers.gsfc.nasa.gov/ems/visible.html