Demonstrations

Standing Waves in a String - Melde's Experiment

Code Number :	3B22.11
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 :	Melde's Experiment
Area of Study :	Acoustics
Equipment :	Plexiglas Box Stand, Reed Vibrator with attached 8 ft. String (Constant Diameter), Pulley, Small Masses and Hanger or the Screw Tension Apparatus, Reed Vibrator with attached green fish line (Tapered/Decreasing diameter vs. Length), Driven Tuning Fork, Mechanical Oscillator, Longitudinal Wave Spring, Amplifier, Wave Generator.
Procedure :	Assemble the apparatus as indicated. By varying the amount of mass or tension on the string you can get from 2 to 11 or 13 standing waves. In the constant diameter string these waves are all the same size. In the decreasing diameter (tapered) string the waves will be of different sizes. For instance there will be 3 waves on one half of the string vs. only 2 on the other half, instead of 3 on each half. This is best seen in the classroom when set high enough to use the blackboards as background. The reed vibrator in the above instructions may be replaced with the driven tuning fork if desired. 2 to 8 VDC of several amps will be needed to run the driven forks.

References

Ana Cros, Chantel Ferrer-Roca, "Excitation of Standing Waves by an Electric Toothbrush", TPT, Vol. 44, # 9, Dec. 2006, p. 578.

Haym Kruglak, "Demonstrations with a Sabre-Saw Oscillator" TPT, Vol. 43, # 7, Oct. 2005, p. 474.

Christine Carmichael and Steven Smith, "Demonstration of Beats With A Double-Driven String", TPT, Vol. 42, # 8, Nov. 2004, p. 462.

Alison Hapka, "Handheld Standing-Wave Generator," TPT, Vol. 38, # 6, Sept. 2000, p. 342.

Richard E. Stevens, "A Simulation of Optical Polarization," TPT, Vol. 38, # 4, p. 222, April 2000.

James H. Larson, "Beats on a Vibrating String," TPT, Vol. 37, # 6, p. 373, Sept. 1999.

Mark Graham, "Melde's Experiment with an Aquarium Aerator," TPT, Vol. 36, # 5, p. 276- 279, May 1998.

John Abendschan and Dick Speakman, "Laser- Enhanced Vibrating String", TPT, Vol. 29, # 2, Feb. 1991, p. 114.

Parshotam D. Gupta, "Coloration on a String Vibrating in a Standing Wave Pattern," TPT, Vol. 26, # 6, p. 371, September 1988.

Gerard Lietz, Anthony Behof, Marshall Ellenstein, "Illuminating Standing Waves", TPT, Vol. 24, # 7, Oct. 1986, p. 449.

C. J. Roddy, "Standing Waves - A New Twist", TPT, Vol. 21, # 6, Sept. 1983, p. 408.

John G. McCaslin, "Standing Transverse Waves of Inhomogeneous Strings", TPT, Vol. 21, # 1, Jan. 1983, p. 53.

Sue Gray Al-Salam, Ronald B. Edge, "Why is the String Colored?", TPT, Vol. 18, # 7, Oct. 1980, p. 518.

Samuel Jacobs, "Can Standing Sound Waves Have Zero Amplitude Nodes?", TPT, Vol. 17, # 7, Oct. 1979, p. 460.

David D. Lockhart, "Standing Wave Generator," TPT, Vol. 9, # 5, May 1971, p. 283, reprinted in TPT, Vol. 41, # 1, p. 54, Jan. 2003.

Haym Kruglak, "Demonstration with a Sabre - Saw Oscillator", TPT, Vol. 8, # 2, Feb. 1970, p. 88.

Timothy C. Molteno, Nicholas B. Tufillaro, "An Experimental Investigation Into the Dynamics of a String", AJP, Vol. 72, # 9, Sept. 2004, p. 1157.

Allan Walstad, "The Longitudinal Momentum of Transverse Traveling Waves on a String", AJP, Vol. 72, # 7, July 2004, p. 971.

David R. Rowland, "Parametric Resonance and Nonlinear String Vibrations", AJP, Vol. 72, # 6, June 2004, p. 758.

Donald E. Hall, "Optical Measurement of String Motion", AJP, Vol. 55, # 6, June 1987, p. 573.

Donald F. Kirwan, Jack Willis, "Direct Measurement of Transverse Wave Speed on a Stretched String", AJP, Vol. 43, # 7, July 1975, p. 651.

"Energy Transfer in Vibrating Strings", TPT, Vol. 5, # 4, April 1967, p. 175.

Sa-9, 10: Freier and Anderson, A Demonstration Handbook for Physics.

W-120: "Melde's String - Sonometer," DICK and RAE Physics Demo Notebook.

S-34, 35: Richard Manliffe Sutton, Demonstration Experiments in Physics.

Charles Taylor, "Demonstration 3.2", The Art and Science of Lecture Demonstration, p. 111.

Ron Hipschman, "Giant Guitar Spring," Exploratorium Cookbook III, 186.1 - 186.3.

"Vibrating String," The Exploratorium Science Snackbook, 103-1

Ron Hipschman, "Vibrating String," Exploratorium Cookbook II, 116.1 - 116.2.

Mail Questions and Comments to: Dale Stille