Demonstrations

Forces on a Dielectric

Code Number :	5C20.22
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..
Condition :	Excellent
Principle :	Forces on Dielectrics
Area of Study :	Electricity & Magnetism
Equipment :	High Voltage Power Supply, Aluminum cylinder electrodes, Silicon Oil, Mineral Oil, 6 inch Petri Dish.
Procedure :	Pour Silicon Oil into the Petri dish to a depth of 1/4 inch. Place the electrodes into the dish and space them about 1/8 in apart. The higher you turn up the voltage on the power supply, the higher the oil will climb in the gap between the electrodes. The oil should rise at least 1 to 1.5 cm up into the gap. Caution: If you turn the voltage up too fast you will get arcing of the electrodes. Turn the voltage down and then up slowly. As the oil rises into the gap you will be able to apply more voltage. If the electrodes are too close together, you will also get continuous arcing between them and the demo will fail. Mineral oil may be substituted for the Silicon oil but it will not rise up into the gap as far.

Web Links

J4-24: Force on Dielectric in Electric Field www.physics.umd.edu/lecdem/services/demos/demosj4/j4-24.htm

EM-c2c: Force on a Dielectric

www.pha.jhu.edu/dept/lecdemo/EM-c2c.html

References

Eric R. Dietz, "Force on a Dielectric Slab: Fringing Field Approach", AJP, Vol. 72, # 12, Dec. 2004, p. 1499.

Mail Questions and Comments to: Dale Stille