Measurement Problem

No.11513780 ViewReplyOriginalReport
Why can't I find some kind of visual proof of the collapse of the wave function? I've seen plenty of double slit experiments where the light acts like a wave but I want to see some kind of proof of it acting like a particle. Feynman said that if a detector were to be placed before the slits and one electron was shot at a time it would act as a particle. Has anyone ever actually done that?