How does it work?
The sphere is part of a so-called Van-de-Graaff generator. A rotating rubber band charges the sphere up to 500,000 Volts. The charge flows through the volunteer’s body and into the rotatable metal propeller. The tips of the propeller are bent by 90 degrees and pointed. When the propeller is charged, a strong electrostatic field arises at the tips and charge is emitted. The surrounding air also becomes charged. Since the tips and the air are both positively charged and like charges repel each other, the motor begins to rotate.
Safety risks
The use of high voltage in this demonstration is safe as only very small currents are involved.
