Light is an energy source that behaves like a wave. The distance between the each wave is called the wavelength. Light of different wavelengths appear as different colors. Here's where you can learn more. It features a Flash movie, followed by a quiz and printable activities.
Color can sway thinking, change actions, and cause reactions.
It can irritate or soothe your eyes, raise your blood pressure or suppress your appetite. This incredibly extensive site is my pick of the day for high school students and adults. The color of an object depends on what happens as light hits it. Objects absorb some colors and reflect others. The colors you see are the colors reflected by the object.