My Solid state physics class just end and my professor referred to the Uncertainty principle about how you can not know the momentum and position of an electron at a given instant but, you can only know one. My question is why ? Why is this phenomena so ? I was going to ask my prof but I had to go to another class. I was hoping someone on here can tell me why and show me a proof, if possible. I have gotten into a bad habit of not taking facts until I know why or have seen the proof.