Firing electrons at a crystal produced a pattern only waves should make
In 1927, Clinton Davisson and Lester Germer scattered electrons off the surface of a nickel crystal and found the intensities peaked at specific angles — the unmistakable signature of wave diffraction, not simple particles bouncing off atoms. The result confirmed Louis de Broglie's three-year-old hypothesis that matter itself has a wavelength, a cornerstone of quantum mechanics. Davisson shared the 1937 Nobel Prize in Physics for the discovery.