Solid and slit aluminum rings are placed around the core of a coil, and the coil is energized with alternating current. The solid ring experiences a strong upward force and jumps off the core due to the induced current and resulting magnetic field that opposes the original field. The slit ring, however, does not jump because the break in the ring prevents the formation of a continuous current, illustrating the necessity of a closed loop for the induction of currents and the resulting forces.