# Static electricity/Howard Community College/fall2014/501 dancing balls

### Team Members

Andy Ha
Joseph Quintana-Gonzales
Marcelo Vargas Palacios

## Problem

• To get the original system set up and re-operational.
• Once operational, manipulate the contents of the box while it is functioning.

## Conceive

Operate device normally, and then use a series or set of prods to manipulate contents.

### Theory of Operation

A Wimshurst Machine is an electrostatic generator consists of two opposite rotating disks with several metal segments attached in equal spacing, metallic brushes, and a spark gap. The entire machine is usually connected to Leyden jars.

According to Wikipedia:

#### What causes the balls to "dance"

The voltage created by the Wimshurst machine is conducted to the aluminum foil plates using copper wire. The voltage of the two aluminum plates are opposite charges. The charge of the bottom plate is transferred to the ball in the box and is then repelled, shooting upwards into the top plate. Since the top plate is an opposite charge, the contact between the ball and plate causes a discharge. The ball then falls back towards the bottom plate and the cycle is repeated.

## Design

### Box & Wiring

We decided to use the same box the previous group created, and wired it the same way.

We used two Wimshurst machines in this project:

• The small one (seen above)
• The large one:

Ultimately we opted to use the larger Wimshurst machine. The small machine lacked the proper bands for operation, using makeshift bands with rubber bands instead. This caused the machine to be less efficient than normal, and generated an insufficient amount of voltage. The larger one, although not self starting, output a sufficient amount of voltage.

To start the large machine, you must first rub a PVC pipe with a silk cloth and then transfer the static charge in the pipe to the machine. Afterwards, it functions as a normal Wimshurst machine. The reason why the large machine is not self starting is because the disks lack the metal sections, lacking a self-activated charge generator.