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
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