• Silver atoms
• Ions
• Electrons

An electron beam passing through a Stern-Gerlach device does not separate into spin-up and spin-down components. The spreading of the electron wave packet washes out the separation effect due to the electron spin. For an inhomogeneous magnetic field of the form , the motion of the particle is in the - plane. The effect of the Lorentz force is masked by the spreading of the electron wave packet.