Demonstrations

Electrophorus

Code Number :	5A10.20
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 :	Good
Principle :	Electrostatics
Area of Study :	Electricity & Magnetism
Equipment :	Electrophorus plate, charging plate, silk, cats fur.
Procedure :	Charge the electrophorus plate by rubbing it with the cats fur. This plate will have a positive charge when this is done. Set the charging plate onto the electrophorus and draw a spark off the back of the plate with your finger. Remove the charging plate from the electrophorus and you should now have a negative charge. The electrophorus should stay charged for several cycles of the charging and discharging operation. The film canisters contain a neon light that will flash in the presence of an electrostatic field.

References

David R. Lapp, "Bigger Cap... Bigger Spark", TPT, Vol. 30, # 8, Nov. 1992, p. 454.

William R. Gregg, "Three Inexpensive High-Voltage Electricity Demonstrations", TPT, Vol. 30, # 7, Oct. 1992, p. 400 - 401.

William Layton, "A Different Light on an Old Electrostatics Demonstration," TPT, Vol. 29, # 1, p. 50, (Jan. 1991).

R. A. Morse, "The Automatic Electrophorous", TPT, Vol. 29, # 4, Apr. 1991, p. 225.

R. D. Edge, "Electrostatics With Soft-Drink Cans", TPT, Vol. 22, # 6, Sept. 1984, p. 396 - 398.

Donald S. Ainslie, "Can an Electrophorus Lose Its Charge and then Recharge Itself ?", TPT, Vol. 20, # 4, Apr. 1982, p. 254.

Donald S. Ainslie, "Inversion of Electrostatic Charges in a Cylindrical Electrophorus", TPT, Vol. 18, # 7, Oct. 1980, p. 530.

Oleg Jefimenko, David Walker, "Electrets", TPT, Vol. 18, # 9, Dec. 1980, p. 651.

John E. Girard, "Negative Charges from an Electrophorus", TPT, Vol. 16, # 6, Sept. 1978, p. 402.

John W. Layman and Delbert J. Rutledge, "Neon Lamps and Static Electricity", TPT, Vol. 10, # 1, Jan. 1972, p. 49.

D. S. Ainslie, "What are the Essential Conditions for Electrification by Rubbing?", AJP, Vol. 35, # 6, June 1967, p. 535.

Ea-19: Freier and Anderson, A Demo Handbook for Physics.

E-140: "Electrophorus," DICK and RAE Physics Demo Notebook.

E-10: Richard Manliffe Sutton, Demonstration Experiments in Physics.

Tik Liem, "The Spark - Producing Finger," Investigation to Science Inquiry, p. 246.

"Charge and Carry," Science Snackbook, p. 20.1 - 20.3.

Mail Questions and Comments to: Dale Stille