描述
In physics, color is associated specifically with electromagnetic radiation of a certain range of wavelengths visible to the human eye. 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. 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.
