Purpose
In this investigation, students will explore the nature of a force. Students will determine whether or not the force is distinct from other known forces.

Discussion
This is an introduction to electrostatic force. It shows students evidence of a force but demands they eliminate gravitational force and magnetic force before giving it a new name. Pith ball electroscopes may be used; or just hang a pith ball on a thread from a convenient support.

Required Equipment
Pith ball suspended from a support rod, vinyl and acetate strips or tubes, wool and silk cloth swatches (2″ x 2″), brick (or a heavy book), bar magnet.