3C20.16 - Ultrasonic Waves - Suspended Rods , Ultrasound

Code Number:
3C20.16
Demo Title:
Ultrasonic Waves - Suspended Rods , Ultrasound
Condition:
Good
Principle:
Audible Frequency Range of the Human Ear
Area of Study:
Acoustics, Biology

Disclaimer

Equipment:
Two sets of ultrasonic rods and a striker.
Procedure:

Strike the rods on the end with the striker.  The shortest rod should have a frequency of 30 KHz which is well above the human range of hearing.  The longest rod should be within the range of human hearing.  With this set the limits of audition can be tested.

A microphone on the oscilloscope can be used to show that sound is still emitted from the bars that you cannot hear.

References:
  • Thomas Allen, Alex Chally, Bradley Moser, and Ralf Widenhorn, "Sound Propagation, Reflection, and Its Relevance to Ultrasound Imaging", TPT, Vol. 57, #3, Mar. 2019, p. 134.
  • Thomas B. Greenslade, Jr., "Marloye's Harp and the Thumb Piano", TPT, Vol. 39, #5, May 2001, p. 310.
  • Thomas B. Greenslade, Jr., "The Acoustical Apparatus of Rudolph Koenig", TPT, Vol. 30, #9, Dec. 1992, p. 518.
  • Thomas B. Greenslade, Jr., "Tonometers", AJP, Vol. 75, #6, June 2007, p. 574.
  • Sf-4: Freier and Anderson, A Demonstration Handbook for Physics.
  • David Goertz and Kullervo Hynynen, "Ultrasound-mediated Drug Delivery", Physics Today, Vol. 69, #3, Mar. 2016, p. 30.
  • Johanna Miller, "Ultrasound Resolution Beats the Diffraction Limit", Physics Today, Vol. 69, #2, Feb. 2016, p. 14.
  • William D. O'Brien Jr, Floyd Dunn, "An Early History of High-Intensity Focused Ultrasound", Physics Today, Vol. 68, #10, Oct. 2015, p. 40.
  • Stanislav Emelianov, Pai-Chi Li, Matthew O'Donnell, "Photoacoustics for Molecular Imaging and Therapy", Physics Today, Vol. 62, #5, May 2009, p. 34.
  • E. Carr Everbach, "Medical Diagnostic Ultrasound", Physics Today, Vol. 60, #3, Mar. 2007, p. 44.
  • Frederick Kremkau, "Seeing is Believing? Sonographic Artifacts", Physics Today, Vol. 60, #3, Mar. 2007, p. 84.
  • Jearl Walker, "3.25, Bat Finding a Flower", The Flying Circus of Physics Ed. 2, p. 156.
  • Jearl Walker, "3.24, Bat Finding an Insect", The Flying Circus of Physics Ed. 2, p. 156.
  • Julien Clinton Sprott, "3.10, Ultrasound", Physics Demonstrations, ISBN 0-299-21580-6, p. 169.

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.