Doorknob spark – rubbing feet to build up charge

Integrated ScienceElectricity & MagnetismAges 13–14

Drag the character's foot back and forth across the rug to build up electrons on the body (each rub is shown as electron dots along the leg and body), then drag the hand towards the metal doorknob. The more electrons have built up, the farther away the hand is when a spark jumps; as soon as the spark discharges, the charge on the body drops to zero and the discharge counter goes up by one. You can adjust the maximum number of electrons and the spark distance per electron to make the link between charge and spark distance clear. Based on the "John Travoltage" simulation by PhET Interactive Simulations, University of Colorado Boulder (CC BY 4.0); rewritten.

Lesson: Charging by friction (static electricity)