When discussion diffraction, a typical experiment to use to demonstrate it is the double-slit experiment. For example, in the historical discussion about corpuscular vs wave theories, they cite Thomas Young's experiment as a proof. Why use double-slit when a single slit works? Is there any specific behavior that works with double-slit only?
Another related question is: do electrons show interference pattern if they pass through a single slit? Since they act like a wave, I would assume they do, but then every single book/source I have read about this only considers double-slit, so not sure.