An alpha-particle produced by radioactive decay leaves a visible continuous track in a Wilson Cloud Chamber. As it collides with and ionizes the molecules of the vapor, its position is constantly being “measured” by the vapor molecules. If a magnetic field is present, its track will be curved and its momentum can be determined based on the degree of curvature (less curvature = more momentum). It seems like the particle’s position and momentum are both being measured precisely at the same time. Where is the Uncertainty Principle in this scenario? Thanks in advance.