Electrostatic Attrac And Repuls - Charged Cylinders
To demonstrate electrostatic attraction and repulsion.
Stand with two glass test tubes and hard rubber rod on strings, silk, fur.
Charge the glass cylinders positive by rubbing with silk, and charge the hard rubber cylinder negative by rubbing with fur. The two positive glass cylinders repel each other, but both are attracted to the negative hard rubber cylinder.◙
Walter Roy Mellen, Inexpensive Electrostatics Halos, TPT 28, 612-613 (1990).