• This lecture is best done by transitioning from the final answer of the Lorentz Force and Work on a Rectangular Loop activity. The term in the final answer contributed from the magnetic dipole moment can be singled out. Then, the general expression

$$U=- \vec{\mu} \cdot \vec{B}$$

can be written on the board.

• In words, the magnetic dipole moment is a measure of how much the current-carrying object's surface normal (which faces the same direction as the magnetic dipole moment vector) wants to face in the direction of the magnetic field.
• Classically, it would be expected that, in the case of the Stern-Gerlach experiment, the silver atoms would all have “rings of charge” (their single shell electron) facing with their normals in random directions. However, the results of the Stern-Gerlach experiment do not reflect this.