Take the bowl and clean thoroughly. Using the Aluminum tape create the pattern on the inside of the bowl shown above.
Ensure that the top of the pattern comes to the top of the bowl. pierce a hole in the middle, bottom of the bowl and stick a wire through the hole use a piece of tape to attach the wire firmly. Connect the top edge of the bowl with another piece of tape an connect this to another wire.
Connect the wires to each of the Wimshurst’s discharge balls, or one wire from the VanDe Graaff top terminal and one wire from the Van De Graaff’s earth to the inner and outer patterns of aluminium strips in the bowl.
Try the supply and ensure that there are no arc overs. If arcing occurs trim some tape off the offending areas.
Create a conductive ping pong ball. (details here Conductive Balls for HV experiments )
With the supply off, throw the ping pong ball into bowl so it runs around the bottom of the bowl. Turn on the supply. The ball should accelerate and maintain a healthy velocity around the bowl.