Demonstrations

Bell in a Vacuum

Code Number :	3B30.30
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 :	Lack of Sound in a Vacuum
Area of Study :	Acoustics
Equipment :	Bell jar with sorbothane pad, vacuum pump, 6 volt battery with attached doorbell.
Procedure :	When put into the bell jar all of the buzzers will experience a great loss of volume. Pads of sorbothane rubber are used to eliminate any vibrations. Hook the bell to 6 volt battery. With the bell ringing evacuated the bell jar with the vacuum pump. As the air is drawn from the jar the sound will diminish. With the vacuum pump running it is hard to hear the bell. The best arrangement is to put the vacuum pump in room 58 and run a vacuum hose from there into the lecture room. A switch will be needed also in the lecture room so that you can turn the pump on from there. Another alternative is to evacuate the bell jar and then shut off the pump. As you then bleed air back into the jar the buzzer will start to sound.

References

Clifford Swartz, "Bell in a Bell Jar - III," TPT Vol. 41, # 6, Sept. 2003, p. 317

Dejun Han, "Improved Bell-in-a-Bell-Jar Demonstration," TPT Vol. 41, # 5, May 2003, p. 278.

David Gavenda, "Bell in a Bell Jar - I," TPT Vol. 41, # 6, Sept. 2003, p. 316

Burt Brody, "Bell in a Bell Jar - II," TPT Vol. 41, # 6, Sept. 2003, p. 317

R.D. Edge, "Simple Vacuum Experiments," TPT, Vol. 25, # 8, p. 523. (November 1987).

Carl H. Hayn, "Christian Huygens and the Bell Jar", TPT, Vol. 11, # 1, Jan. 1973, p. 103.

Leonard Eisner, "Transistor Radio in an Evacuated Bell Jar", TPT, Vol. 10, # 1, Jan. 1972, p. 47.

Robert Frizzell, "Bell in a Vacuum Demonstration", TPT, Vol. 9, # 3, March 1971, p. 153.

Alfred M. Eich, Jr., "Sound in Vacuum Demonstration", TPT, Vol. 6, # 8, Nov. 1968, p. 428.

Sh- 2: Freier and Anderson, A Demonstration Handbook for Physics.

W- 015: "Bell in Vacuum," DICK and RAE Physics Demo Notebook.

"169, A Bell Ringing in a Bell Jar," Christopher P. Jargodzki and Franklin Potter, Mad About Physics, p. 62, 206.

Alfred M Eich, "Sound in a Vacuum Demonstration," Apparatus for Teaching Physics.

John H. Moore, Christopher C. Davis, Michael A. Coplan, "Kinetic Theory," Building Scientific Apparatus 2^nd Edition, p. 76-77.

Raymond Bruman, "No Sound Through Empty Space," Exploratorium Cookbook I, 65.1 - 65.3.

Robert Frizzell, "Bell in a Vacuum Demonstration," Apparatus for Teaching Physics, p. 243.

Mail Questions and Comments to: Dale Stille