The device is called a Van de Graaff generator. Science museums and research facilities have large versions that generate potentials in the hundreds of thousands of volts.
Ours is more modest, but is still capable of drawing 1/2 inch sparks from the soda can to my finger. The spark is harmless, and similar to the jolt you get from a doorknob after scuffing your feet on the carpet.
To build the toy, you need:
An empty soda can
A small nail
A rubber band, 1/4 inch by 3 or 4 inches
A 5×20 millimeter GMA-Type electrical fuse (such as Radio Shack #270-1062)
A small DC motor (such as Radio Shack #273-223)
A battery clip (Radio Shack #270-324)
A battery holder (Radio Shack #270-382)
A styrofoam cup (a paper cup will also work)
A hot glue gun (or regular glue if you don’t mind waiting)
Two 6 inch long stranded electrical wires (such as from an extension cord)
Two pieces of 3/4 inch PVC plumbing pipe, each about 2 or 3 inches long
One 3/4 inch PVC coupler
One 3/4 inch PVC T connector
Some electrical tape
A block of wood
That sounds like a lot of stuff, but take a look at the step-by-step photos below, and you will find that the whole project can easily be put together in an evening, once all the parts have been collected.
We’ll start at the bottom, and work our way up.
Visit Here for more.