5A40.36 - Van de Graaff - Ball and Snake

Code Number:
Demo Title:
Van de Graaff - Ball and Snake
Area of Study:
Electricity & Magnetism
Van de Graaff generator, conducting ball on string, metal ribbon on a rod (snake).

Start the Van de Graaff and bring the ball on the string to the dome.  At some point the ball will be attracted to the dome and touch it.  After this the ball will be repelled from the dome until it is discharged with the discharge rod.  The snake on the other hand, do to its long pointed configuration will leak charge rapidly.  This results in the snake repeatedly being attracted and repelled from the dome.

  • Walter Roy Mellen, "Inexpensive Electrostatic Halos", TPT, Vol. 28, #9, Dec. 1990, p. 612.
  • Robert J. Krohl, "Electrostatic Pong", TPT, Vol. 20, #5, May 1982, p. 330, also A Potpourri of Physics Teaching Ideas - Electricity and Magnetism, p. 132.
  • Ec-5: "Forces Between Electrodes", Freier and Anderson, A Demonstration Handbook for Physics.
  • Grant Mellor, "The Tinsel Whip", Flying Tinsel, 1993, p. 48-50.
  • Rudolf F. Graf, "The Hindu Thread Trick", Safe and Simple Electrical Experiments, p. 33.

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