String instrument (sonometer)
String instrument (sonometer)
String instrument (sonometer)

 

Code Number: 3D20.20

Demo Title: Sonometer on Oscilloscope

Condition: Good

Principle: Frequency of Sound Waves

Area of Study: Oscillations & 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.