Disclaimer:

Reprinted by permission of Dick Berg, University of Maryland, for use on this website.

The demonstrations contained and referenced herein are listed for the purposes of cataloging and describing physics demonstrations which should be conducted only under the direction of a trained instructional support professional or physicist. These demonstrations are not presented for the purpose of being conducted by persons unconnected to this Facility and/or persons not consulting with or being supervised by the recognized instructional support professional or physicist and his/her staff. The University is responsible only for those demonstrations carried out using its own equipment using established safety and scheduling policies, and bears no responsibility for those choosing to use this source material for their own purposes. All demonstrations described and contained herein are public domain, and can also be found in reference materials in libraries, bookstores, and electronic sources.

Further information regarding legal liability in use of demonstrations and labs will be found on the web site Injuries in School/College Laboratories in USA.

The University of Iowa Disclaimers:  University of Iowa Disclaimer All Rights Reserved..

The glass rod and silk as well as the clear Lucite rod and silk will give a positive charge. 

The ebonite and cats fur will be negatively charged as will the PVC rod and cats fur. 

The Lucite and PVC rods will be charged only where the rod was rubbed.  

A set of balloons on strings can also act like a large set of pith balls when charged.

Once the set of pith balls or balloons have the same charge they should repel each other and be attracted to a rod of the opposite charge.  A rod with the same charge as the pith balls should show repulsion.