Equipment:

• rods, fur, and silk - shelf 14E

Theory: When neutral objects made from different insulating materials are rubbed together, one will generally acquire electrons from the other. Which becomes negatively charged, and the degree to which charge is transferred, is dictated by where the materials fall in the triboelectric series.

Description: The clear acrylic rods will be positively charged when rubbed with the black silk. You should be able to hear the snap, crackle, and pop as the charge builds up. The black plastic rods will be negatively charged when rubbed with the red wool, the fur, or the small blue cloth. In humid conditions, the blue cloth gives the best results.

Setup time: 5 minutes

References: (available in the demo room)

• Carpenter and Minnix, "The Dick and Rae Physics Demo Notebook", E-010.
  That's a list of the tribolelectric series.