  Electrons moving at slow speeds much lower that the speed of light are
described by a wave function which is a solution of Pauli's equation. This is a
low velocity limit of the relativistic Dirac equation. Here we compare two
approaches, one which is the more conservative Copenhagen's interpretation
denying a trajectory of the electron but allowing a trajectory to the electron
expectation value through Ehrenfest theorem. The said expectation value is of
course calculated using a solution of Pauli's equation. A less orthodox
approach is championed by Bohm, and attributes a velocity field to the electron
also derived from the Pauli wave function. It is thus interesting to compare
the trajectory followed by the electron according to Bohm and its expectation
value according to Ehrenfest. Both similarities and differences will be
considered.
