Dispersion Reveals Coffee at the End of the Rainbow

Light bounces off a mirror and refracts through an empty glass to produce a rainbow of color
Light bounces off a mirror and refracts through an empty glass to produce this rainbow of color.
Image Credit: Amanda Palchak 

April 13, 2016

In this photograph, morning light from a nearby window was reflected off of a mirror located on an opposing wall. The light was then refracted through an empty glass, after which an eye-catching display of dispersion was projected onto my morning cold brew coffee. Dispersion shows that light of different wavelengths is refracted at different angles. Sunlight, which is white light, is a combination of all colors in the visible spectrum. Each color in the spectrum has a differing wavelength, increasing from the blue end of the spectrum to the red end of the spectrum. As white light passes through glass, these differing wavelengths bend at varying angles, revealing the colors of the rainbow.

—Guest post by Amanda Palchak, Physics Instructor at Mississippi Gulf Coast Community College.