Waves vs. Particles The distinction between waves and particles becomes rather blurred in light of quantum mechanics. The photoelectric effect tells us that light can behave as though it's made of particles, while "particles" like the electron, as de Broglie first suggested, sometimes act like waves. Thomson was certainly correct in concluding that his negatively charged cathode rays weren't electromagnetic waves (or photons), which have no electric charge--but it isn't quite fair to say that electrons are not waves at all. Interestingly, J. J. Thomson's son, G. P. Thomson, performed one of the famous experiments showing that electrons, like waves, can produce interference patterns. J. J. won the Nobel Prize for showing that electrons are particles; his son won the Nobel Prize for showing that electrons are waves--and they were both right!

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