This is the 2007 version. Click here for the 2017 chapter 04 table of contents.

Color Vision

For centuries scientists wondered how humans perceived color. The scientific study of color vision began with a classic 1666 experiment by Isaac Newton. He was fascinated by glass prisms he obtained at the Stourbridge Fair, an international trade exposition. As you probably know, a triangular glass prism produces a rainbow of colors when struck by light from the sun. Newton realized this might be a clue to the nature of color.

Why did a triangular glass prism fascinate Isaac Newton? What did he speculate?

Newton observed how a prism splits light into a rainbow of colors

Coming home with a prism he purchased at the fair, Newton set up a dark room where a small amount of light could be admitted into the room through a hole. Newton placed the prism in front of the beam of light, producing a rainbow of colors on the wall. Contemplating this phenomenon, Newton decided the prism must bend each color by a different amount, resulting in the rainbow display.

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