The electrostatic generator needs a place to store and build up an electric charge. Without the capacitor, a static generator such as the one made with PVC pipe would have to be operated in a very dark room in order to see any sparks produced. The capacitor stores up enough of a charge to make a very visible spark in broad daylight and, can also be heard.
The picture of the film can leyden jar is self explanatory. Now days, a film "can" is really plastic but it is a kind of plastic that makes a great capacitor. The inside foil can be taped to the wall or secured any way you want, so long as it makes good contact with the wall. One person wrote back and reported that the film can exploded as a result of using rubber cement to glue the inside foil to the wall. Rubber cement is highly flammable and explosive and was set off by sparking inside.
* An empty film canister with its lid
* Multistrand insulated wire
* Single conductor/solid uninsulated wire, about 1.5mm in diameter
* Some aluminum or copper foil (NOTE: Any conductive foil will work. Copper foil is thicker and easier to work with than aluminum foil, but aluminum foil works if that’s all you have.)
* A screw with a round head that is shorter than the film canister’s height
* Two nuts that fit on the screw
* Scotch tape
* optional. A PVC Pipe, 3/4″ wide and about 3 or 4 feet long.
* optional. Fur, wool, or cotton fabric
Now that you have all of the parts, let’s get to work. First, drill (or poke) a hole in the center of the lid of the film canister. The hole should be just wide enough to allow the screw to fit snugly inside it. Next, cut a rectangle of foil large enough to wrap around the outside of the canister, and about 2/3 of the height of the canister. Tape the foil to the canister, being sure to leave an open section for a loop of wire to go around the canister over the foil (you should just need to tape the foil’s edges to the outside of the canister.) This is...