Electrophorus

The electrophorus is a device that can be electrostatically charged. The metal base plate will become strongly charged when rubbed with fur. If you now take a large disk-shaped metal plate with an insulating handle and place it on the plate, the face becomes positively charged by induction while the other side acquires the opposite charge. If the demonstrator now touches the back plate, thus conducting away the charge on the back, and then removes the plate by the handle, it will have a net positive charge. Bring this near an electroscope to show it is charged.

* Equipment seen in the video may vary from equipment used in ND Demonstrations. See information and images below for ND equipment and setup.