Cathode Ray Tube with Pinwheel

Charged particles strike the phosphor-coated blades of a pinwheel, causing the phosphor to glow and the wheel to rotate, demonstrating that charged particles have mass.

Narration

In this cathode ray tube, the charged particles that are generated strike the blades of the pinwheel, causing the phosphor to glow and the wheel to rotate. This demonstrates that the charged particles have mass, since their momentum has been transferred to the pinwheel.