In the early 20th century a simple electrostatic device known as the van de Graaf generator, named after its principal inventor, was brought into use. The van de Graaf generator permits the build up of several tens of kilovolts, or higher, in a laboratory setting, without posing substantial danger to someone that touches it. The relatively high voltages created by the van de Graaf are useful for a variety of physics applications, both simple and advanced.

Explain the design of the van de Graaf generator, and use the principles of resistance discussed this week to explain how the high electric potential is built up on the generator. Identify a practical experimental use of the van de Graaf generator, and also explain why it does not pose a lethal threat to people, despite its high voltages.