If electrons are fired through a thin piece of graphite towards a screen an interference pattern forms.We can explain this by thinking of the electrons as having a wavelength, called the de Broglie wavelength. Electrons can be calculated to have wavelengths comparable to the spacing between the atoms in the graphite. As such, it diffracts on passing between atoms and interferes with itself.It is important to highlight that each individual electron lands in one place and this pattern emerges when many electrons are fired through. This, and other compelling evidence, suggests it is better to think of these waves as probability waves, not anything physically real.