Persistence Of Vision - Magic Wand
Demonstrate persistence of vision in a neat way.
Slide projector with slide of Einstein, white stick pointer.◙
The slide of Einstein (or any of your favorite slides) is focused a few feet from the projector, but unfocussed where it strikes any surface on which it might be identifiable. When a white stick pointer is moved rapidly up and down through the focal plane the image of Einstein can easily be identified. It's persistence of vision, folks.