Color is the aspect of things that is caused by
differing qualities of light being reflected or emitted by them.
To see color, you have to have light. When light
shines on an object some colors bounce off the object and others are absorbed
by it. Our eyes only see the colors that are bounced off or reflected.
The sun’s rays contain all the colors of the
rainbow mixed together. This mixture is known as white light. When white light
strikes a white crayon or marker barrel, it appears white to us because it
absorbs no color and reflects all color equally. A black crayon or marker cap
absorbs all colors equally and reflects none, so it looks black to us. While
artists consider black a color, scientists do not because black is the absence
of all color.
All light rays contain color. Light is made of
electromagnetic waves. These waves spread out from any light source, such as
the sun. Light waves travel at tremendous speed (186,000 miles or 300,000
kilometers per second). Different colors have different wavelengths, which is
the distance between corresponding parts of two of the waves. The longest
wavelength of light that humans can see is red. The shortest is violet.
Ultraviolet has an even shorter wavelength, but humans cannot see it. Some
birds and bees can see ultraviolet light. Infrared has a longer wavelength
than red light, and humans can not see this light but can feel the heat
infrared generates.