22.3.2—And interpret qualitatively the evidence provided by electron diffraction

When electrons pass through a thin crystal or narrow spacing, they can form diffraction patterns rather than only particle-like spots.

The pattern is explained by a wavelength associated with the moving electrons; changing electron momentum changes the spacing of maxima and minima.

A ring pattern from a polycrystalline film is evidence of constructive interference from many crystal orientations.

Diffraction does not say an electron is a classical water wave; it reveals wave-like interference in the probability description.