Lenz's Law in action, lots of good demos online, or take any strong magnet and move it rapidly while in close proximity to any non-magnetic conductor (brass, co

Lenz's Law in action, lots of good demos online, or take any strong magnet and move it rapidly while in close proximity to any non-magnetic conductor (brass, copper, aluminum, etc.) You can feel the force exerted by the generated field. Automobile speedometers used to operate on this principle.