Newton’s Color wheel

Newton discovered that white light is composed of visible colors: red, orange, yellow, green, blue, and violet, based on his prism experiments.

Newton was the first to understand what a rainbow really is: he used a prism to refract white light and split it into its basic colors—red, orange, yellow, green, blue, and violet. This is known as Newton’s Prism.

By directing sunlight through a glass prism, the light is refracted due to the change in speed at which light travels within the prism. But white light is made up of various colors, and so each color (that is, each wavelength) is refracted at a different angle within the prism. This causes a rainbow of colors to spread out before our eyes, from red to violet.

This experiment helped us understand that white light is a mixture of all the above colors: red, orange, yellow, green, blue, and violet. (Let’s remember these six basic shades.) Furthermore, let’s not forget that a rainbow is actually a continuous spectrum of colors, in which all the intermediate shades between the above colors also appear.

When we combine these colors again, we get white light once more. So, when the color wheel spins as fast as possible—either manually with a crank or using electricity—we see white light.