In a message dated 12/28/98 6:16:17 PM, John Couture wrote: <<The Van de Graaff terminal is always negative. >> John, depending on its design, a Van de Graaff can be either negative or positive. Wabash Instruments sells them in both configurations and a matched set gives quite a spark! Robert Krampf Science Education Company http://members.aol.com/krampf/home.html Get my Free Experiment of the Week by sending an e-mail to krampf@aol.com