Color

Color is what your eyes and brain see when light bounces off an object. Every color you have ever seen is really light. Without light, there is no color at all. A red apple in a totally dark room is not red. It has no color until light shines on it.

Light from the Sun looks white, but it is actually made of many colors mixed together. You can see this when sunlight passes through raindrops and makes a rainbow. You can also see it if you shine a flashlight through a glass prism. The prism splits the light into a band of colors: red, orange, yellow, green, blue, and violet.

So why is an apple red? When sunlight hits the apple, the skin soaks up most of the colors. It bounces the red light back. That bounced light travels to your eyes. A leaf looks green because it bounces green light back and soaks up the rest. A white shirt bounces almost all the colors back at once. A black shirt soaks up almost all of them, which is why black clothes feel hotter in the sun.

Your eyes pick up color with tiny cells called cones. Most people have three kinds of cones. One kind reacts most to red light, one to green, and one to blue. Your brain mixes the signals together to make every color you see. About one in twelve boys is color blind, which usually means one kind of cone does not work well. Red and green can look almost the same to them.

Other animals see color differently. Dogs only have two kinds of cones, so their world looks mostly yellow, blue, and gray. Bees can see ultraviolet light, which is invisible to humans. Many flowers have hidden patterns that glow in ultraviolet and guide bees to their nectar. The mantis shrimp has up to sixteen kinds of color cells. Scientists are not sure what its world looks like, and they cannot really picture it.

Artists mix color in two different ways. When you mix paints, the main colors are red, yellow, and blue. Mixing them makes darker colors, because each paint soaks up more light. When you mix light, like on a TV or phone screen, the main colors are red, green, and blue. Mixing those makes brighter colors, and all three together make white.