3D20.20 - Sonometer on Oscilloscope

Plug the electromagnetic pickup into the amplifier and the amplifier into the oscilloscope. Bring the pickup close to the string. Pluck the string and the sinusoidal waveform will be shown on the oscilloscope. Harmonics will also show up if the sonometer is plucked or bowed properly. Depending on which wave generators you use you may need to have a frequency meter. A Nucleus Scaler-Timer may be used if desired.
Code Number:
3D20.20
Demo Title:
Sonometer on Oscilloscope
Condition:
Good
Principle:
Frequency of Sound Waves
Area of Study:
Acoustics
Equipment:
String instrument (sonometer), Tektronix 2235 Oscilloscope, Scaler-Timer (Nucleus), Frequency Meters, Electromagnetic Pickup and Microphone.
Procedure:

Plug the electromagnetic pickup into the amplifier and the amplifier into the oscilloscope. Bring the pickup close to the string. Pluck the string and the sinusoidal waveform will be shown on the oscilloscope. Harmonics will also show up if the sonometer is plucked or bowed properly. Depending on which wave generators you use you may need to have a frequency meter. A Nucleus Scaler-Timer may be used if desired.  

References:
  • Antonio Eff-Darwich, "The Electric Monochord: A Musical Demonstration About Electromagnetic Induction", TPT, Vol. 59, #9, Dec. 2021, p. 694.
  • Kouichi Ishikawa, Norihiro Sugimoto, "Deconstructing a Complex Waveform", TPT, Vol. 52, # 3, March 2014, p. 182.
  • Tristan Odekirk, William V. Slaton, "Pulse Speed on a Plucked Wire", TPT, Vol. 50, # 4, Apr. 2012, p. 244. 
  • G. R. Davies, "A "Relevant" Demonstration", TPT, Vol. 33, # 1, Jan. 1995, p. 58.
  • Ray Scott Wakeland and Bennet Brabson,  "Wave Speed on a String Revisited",  TPT, Vol. 28, # 1, p. 57, January 1990.
  • Cliff Swartz - Comments,  TPT, Vol. 28, # 9, Inserted between p.  608 and 609, Dec. 1990.
  • Roger Hanson, "Optoelectronic Detection of String Vibration", TPT, Vol. 25, # 3, p. 165, March 1987.
  • J. L. Sandoval and A. V. Porta, "Fourier Analysis for Vibrating String's Profile Using Optical Detection", AJP, Vol. 53, #12, Dec. 1985, p. 1195.
  • Gordon E. Jones and Joe L. Ferguson, "Easy Displacement Versus Time Graphs for a Vibrating String: Tuning a Guitar by Television", AJP, Vol. 48, #5, May 1980, p. 362.
  • Sj-1, 2:  Freier and Anderson,  A Demonstration Handbook for Physics.
  • B- 240:  "Piano Wire and Strong Magnet",  DICK and RAE Physics Demo Notebook.
  • M- 916:  "Wire in Magnetic Field",  DICK and RAE Physics Demo Notebook.
  • W- 310:  "Square Wave in Vibrating Wire",  DICK and RAE Physics Demo Notebook.
  • W- 390:  "Music and Voice on Microphone",  DICK and RAE Physics Demo Notebook.

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.