CERN — the European Organization for Nuclear Research

Salad Bowl Accelerator



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This was one of the CERN workshops at the Expanding your Horizons event in Geneva ( Similar initiative than the one presented here:


Materials Needed (per bowl):

  • Generator: we used a Wimshurst machine, hand operated, produces a direct current
  • A salad bowl, non metallic
  • Electrically Conductive Adhesive Transfer Tape (two sizes)
  • Wires (banana/alligator) at least 2 per bowl
  • Styrofoam balls
  • Graphite spray
  • Scissors
  • Assorted items: air-drier (for the generator), band aid and alcohol, meter, wood spoons for operate the balls, paper towels, voltmeter, multiplug adapter, cardboard box to spray the balls on, toothpick to hold the balls while spraying them and while drying



Wire the bowls with the conducting tape: make a cross with two long tapes that passes through the middle of the bowl at least one going over the border to the outside of the bowl. Then, put 4 shorter lines of tape in the middle of the sections made by the cross, all of them going over the border of the bowl, use a long tape to connect the 4 strips outside the bowl, without touching any of the border of the main “cross”.

Connect one of the two cables (banana) to one of the strips of the cross, and the other to one of the other strips (or the connecting one). Connect the bowl to the generator.

Coat a Styrofoam ball with graphite. Power the bowl with the machine, throw the ball on it and see it run!



If you use the Styrofoam ball directly without the coat of graphite, it won’t be accelerated. Once the ball is conductive, it will be charged negatively and positively by the strips of the bowl (powered by the generator) and will be moved accordingly by the negative and positively charged strips.

Why my ball does not turn?

Maybe it is too big; make tests with smaller balls in that case.



Before touching the metal parts of the generator, salad bowl, or cables, always put the metal balls of the generator together to discharge!

General remarks:

  • Do not touch the generator
  • Do not touch the ball inside the bowl after electricity circulated, use a spoon
  • Conductor strips may cut your fingers!!
  • Open a window while spraying the balls, ventilation needed
  • Use gloves
Post date: Thu, Jan 16, 2014 — 11:43
Updated date: Tue, Feb 25, 2014 — 14:59

Learning Topics

Process of Discovery