Prismatic coloration: how Newton showed different colors of light behave differently

Image credit: The Dark Side of the Moon, Pink Floyd, 1973

When one of the greatest scientific minds of all time, Isaac Newton, shut himself in a dark room for weeks, it was a safe bet that he would emerge with discoveries that would shift the paradigm of some field of physics or mathematics. This turned out to be true, when in 1666, Newton became fascinated with the effects that a triangular glass prism had on a narrow beam of sunlight; namely, the apparent emergence of a spectrum of colored light. The prevailing hypothesis in the field explained this spectrum as an effect inherent to the prism; that is, all light (of any color) will be separated into a spectrum by a prism. Newton intelligently placed a second prism in the light path of the first to observe that the spectral light could be recombined back into white light. Newton therefore showed that different colors of light "refract" differently through glass.

• A letter of Mr. Isaac Newton, Professor of the Mathematicks in the University of Cambridge; containing his new theory about light and colors: sent by the author to the publisher from Cambridge, Febr. 6. 1671/72; in order to be communicated to the R. Society. Phil. Trans. 1671 6, 3075-3087.

Other readings:

-Interactive demonstration of Newton's two prisms

-Summary of Newton's, Herschel's, and Ritter's experiments on the spectrum of light

-Waters R, Gilmour D, Mason N, Wright R. "The Dark Side of the Moon." 1973. Harvest Records.