3B22.11 - Standing Waves in a String - Melde's Experiment

Code Number:
Demo Title:
Standing Waves in a String - Melde's Experiment
Melde's Experiment
Area of Study:
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, and Wave Generator.

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.

The Cenco 60 Hz. mechanical drivers also come with a version of the Melde's experiement using Aluminum, Steel, and Copper wires of different diameters which can easily be set up with any of the other mechanical drivers we have if desired.   

  • Peter Riggs, "Revisiting Standing Waves on a Circular Path", TPT, Vol. 59, #2, Feb. 2021, p. 100.
  • G. Bozzo, F. de Sabata, S. Pistori, and F. Monti, "Imaging and Studying Standing Waves with a Homemade Melde-Type Apparatus and Information and Communication Technology (ICT)", TPT, Vol. 57, #9, Dec. 2019, p. 612-615.
  • Dylan Welsch, and Blane Baker, "Wavelength Variation of a Standing Wave Along a Vertical Spring", TPT, Vol. 56, #3, Mar. 2018, p. 154. 
  • Cameron T. Vongsawad, Mark L. Berardi, Tracianne B. Neilsen, Kent L. Gee, Jennifer K. Whiting, and M. Jeannette Lawler, "Acoustics for the Deaf: Can You See Me Now?", TPT, Vol. 54, #6, Sept. 2016, p. 369.
  • Paul Gluck, "Standing Waves in a Nonuniform Medium", TPT, Vol. 49, #2, Feb. 2011, p. 76.
  • John Welch, "Demonstrating Wavelength Dependency on Medium Density", TPT, Vol. 47, #7, Oct. 2009, p. 476.
  • Ana Cros and Chantel Ferrer-Roca, "Excitation of Standing Waves by an Electric Toothbrush", TPT, Vol. 44, #9, Dec. 2006, p. 578.
  • Haym Kruglak and Thomas B. Greenslade Jr., "From Our Files: 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.
  • David D. Lockhart and Thomas B. Greenslade Jr., "From Our Files: Standing Wave Generator", TPT, Vol. 41, #1, Jan. 2003, p. 54.
  • James H. Larson, "Beats on a Vibrating String", TPT, Vol. 37, #6, Sept. 1999, p. 373.
  • Mark Graham, "Melde's Experiment with an Aquarium Aerator. Rich Dynamics with Inexpensive Apparatus", TPT, Vol. 36, #5, May 1998, p. 276.
  • Walter Connonny, John Abedschan, 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, Sept. 1988, p. 371.
  • Gerard Lietz, Anthony Behof, and 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.
  • Verner Jensen, "Standing Transverse Waves of Inhomogeneous Strings", TPT, Vol. 21, #1, Jan. 1983, p. 53.
  • Sue Gray Al-Salam and 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, Jan. 2003, p. 54.
  • Haym Kruglak, "Demonstration with a Sabre - Saw Oscillator", TPT, Vol. 8, #2, Feb. 1970, p. 88, reprinted in TPT, Vol. 43, #7, Oct. 2005, p. 474.
  • Marvin Ohriner, "Standing Waves by a Current Carrying Conductor", TPT, Vol. 5, #6, Sept. 1967, p. 287.
  • "Problems: Energy Transfer in Vibrating Strings", TPT, Vol. 5, #4, Apr. 1967, p. 175.
  • Timothy C. Molteno and 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.
  • E. Kashy, D. A. Johnson, J. McIntyre, S. L. Wolfe, "Transverse Standing Waves in a String With Free Ends", AJP, Vol. 65, #4, Apr. 1997, p. 310.
  • Donald E. Hall, "Optical Measurement of String Motion", AJP, Vol. 55, #6, June 1987, p. 573.
  • John A. Elliot, "Nonlinear Resonance in Vibrating Strings", AJP, Vol. 50, #12, Dec. 1982, p. 1148.
  • F. P. Clay Jr., and R. L. Kernell, "Standing Waves in a String Driven By Loudspeakers and Signal Generators", AJP, Vol. 50, #10, Oct. 1982, p. 910.
  • Donald F. Kirwan and Jack Willis, "Direct Measurement of Transverse Wave Speed on a Stretched String", AJP, Vol. 43, #7, July 1975, p. 651.
  • "W-120: Melde's String - Sonometer", DICK and RAE Physics Demo Notebook.
  • Freier and Anderson, "Sa-9, 10", A Demonstration Handbook for Physics.
  • S-34, 35: Richard Manliffe Sutton, Demonstration Experiments in Physics.
  • Martin C. Sagendorf, "Vibrations in a String",  Physics Demonstration Apparatus, 2009. p. 74.
  • A. D. Bulman, "Maintained Fork and Melde Arrangements", Model-Making for Physics, p. 59.
  • Roger J. Hanson, Edited by Karl Mamola, "Optoelectronic Detection of String Vibration", Apparatus for Teaching Physics, p. 74.
  • Jearl Walker, "1.183, Oscillating Car Antenna", The Flying Circus of Physics Ed. 2, p. 79.
  • 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, p. 103-1.
  • Ron Hipschman, "Vibrating String", Exploratorium Cookbook II, p. 116.1 - 116.2.

Disclaimer: These demonstrations are provided only for illustrative use by persons affiliated with The University of Iowa and only under the direction of a trained instructor or physicist.  The University of Iowa is not responsible for demonstrations performed by those using their own equipment or who choose to use this reference material for their own purpose.  The demonstrations included here are within the public domain and can be found in materials contained in libraries, bookstores, and through electronic sources.  Performing all or any portion of any of these demonstrations, with or without revisions not depicted here entails inherent risks.  These risks include, without limitation, bodily injury (and possibly death), including risks to health that may be temporary or permanent and that may exacerbate a pre-existing medical condition; and property loss or damage.  Anyone performing any part of these demonstrations, even with revisions, knowingly and voluntarily assumes all risks associated with them.