Kelvin water drop electrostatic charge generator.

Kelvin water-drop generator: Falling charged water drops light neon bulbs. Water flows from a reservoir and drips through two nozzles at points 1 and 5. When the water valve is first opened, the water drop at 1, at the time when the drop separates from the nozzle, is either positive or negative. Say it is negative. To make the system neutral, the drop at 5 is positive. The negative drop lands in the plastic catch cup at 3. The bottom of the cup is connected via metal screws to a conductive metal plate at 4, which is connected by wire to the metal ring at 6. Thus, the ring at 6 becomes more negative, causing the next drop at 5 once again to be positive, by induction. The drops landing in catch cup 7 are positive, and make an electrical connection to the metal ring at 2, making the ring more positive. This causes the next drop at 1 to be negative, by induction. The cycle repeats until a large amount of negative charge is in cup 3, and a lot of positive charge is in cup 7. When enough charge is stored, sparks jump across the two spark gaps, and the bank of neon bulbs flash. There are a lot of flashes before the water reservoir is drained. NOTE: Use water volume less than 2 of the catch cups, so it won't overflow. Adjust to fast drip, breaking from a stream to drips within the metal rings.