I've recently been doing some learning about the double slit experiment and a bit about how, qualitatively, quantum electro dynamics works. Something that I wondered about for a long time was how momentum could be conserved in these systems when we assume that a particle could land in any number of positions. I kept thinking; couldn't we do the double slit experiment and just measure the velocity of the particle before it reaches the slits so that we know which one it goes through and where it hits after that? Then I realized that the uncertainty principle states that we can't know both the position and velocity beyond a certain uncertainty. I just want to check if this is a correct interpretation of this principle. Is it fair to look at the double slit experiment as a result of our fundamental uncertainty about where the particle is and where it's moving? Is it possible to get similar results by assuming particle-like motion where we just don't know where the particle starts or which direction its moving? Note, I'm not saying that this is why the double slit experiment works the way it does. I just want to know if this is a valid alternative way of modeling it.