Demonstrations

Franck-Hertz

Code Number :	7B30.20
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 :	Quantization of Energy Absorption
Area of Study :	Modern Physics
Equipment :	Franck Hertz apparatus with oven and power supply, digital thermometer, and oscilloscope.
Procedure :	Plug the power supply into the oven observing the correct connections by symbol. Turn the oven to about 200 degrees C and let warm up for at least 50 minutes. NOTE: The heater thermostat on the unit allows the temperature to swing 10 to 20 degrees C under normal operation. It is better to crank the thermostat to maximum, and then regulate the heater with a variac. 90 to 95 volts should give you a temperature of about 200 degrees C and keep it within two degrees of this. Put the oscilloscope on xy plot and turn up the acceleration and heater knobs until peaks are observed. By adjusting the acceleration, heater and RF knobs you should be able to fine tune the system to see at least 7 peaks and as many as 11.

References

Budford L. Williams, "The Franck-Hertz Experiment Using A Thyratron", TPT Vol. 6, # 6, Sept. 1968, p. 322.

Andrew Ahlgren, " A Modified Experiment with the Franck-Hertz Apparatus", TPT, Vol. 2, # 6, Sept. 1964, p. 282.

Daniele Faccio, Matteo Clerici, Davide Tambuchi, "Revisiting the 1888 Hertz Experiment", AJP, Vol. 74, # 11, Nov. 2006, p. 992.

Gerald Rapior, Klaus Sengstock, Valey Basv, "New Features of the Franck-Hertz Experiment", AJP, Vol. 74, # 5, May 2006, p. 423.

W. Fedak, D. Bord, C. Smith, D. Gawrych, and K. Lindeman, "Automation of the Franck-Hertz Experiment and the Tel-X-Ometer X-Ray Maching Using LABVIEW", AJP, Vol. 71, # 5, May 2003, p. 501.

G. F. Hanne, "What Really Happens in the Franck-Hertz Experiment with Mercury?", AJP, Vol. 56, # 8, Aug. 1988, p. 696.

F. H. Liu, "Franck-Hertz Experiment With Higher Excitation Level Measurements", AJP, Vol. 55, # 4, Apr. 1987, p. 366.

Wendell J. Caley, Jr., "Suggestions on "An Automated Franck-Hertz Experiment", AJP, Vol. 40, # 12, Dec. 1972, p. 1877.

R.E. Adelberger, K. F. Kinsey, "An Automated Franck-Hertz Experiment", AJP, Vol. 40, # 2, Feb. 1972, p. 349.

J. Rosenfeld and C. Tyler, "Homemade Franck-Hertz Tube, AJP, Vol. 33, # 10, Oct. 1965, p. 849.

Mail Questions and Comments to: Dale Stille