Laymen and hobby student of physics here. So the only things I know (or at least think I know) I watch from documentaries.
In the test to see if an electron is a particle or wave, they say that if you place a viewer before the slits that the resulting pattern on the back wall is a particle result. But if you aren't placing a viewer before the slit the resulting pattern on the back wall is wave interference.
So how is watching the result on the back wall itself NOT placing a viewer thereby always causing the electron to act as a particle?
Thank you in advance!
Patrick