Demonstrations

Range of Hearing for the Human Ear

Code Number :	3C20.10
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 :	Audible Frequency Range of the Human Ear
Area of Study :	Acoustics, Biology
Equipment :	Wave generator, Amplifier, Speaker (large), Microphone, Tektronix 2235 oscilloscope, Stereo Preamp, Decibel Meter (Radio Shack), Frequency Meter (If Needed).
Procedure :	Plug the generator into the auxiliary input of the amplifier and attach a speaker. Plug the microphone into the preamp and the preamp into the oscilloscope. Use the oscilloscope to show that there is sound produced in the inaudible range. The decibel meter may be used in place of the oscilloscope setup to show that there is still damaging levels of sound produced (Infrasound etc.) in the inaudible ranges.

Web Links

http://hyperphysics.phy-astr.gsu.edu/hbase/sound/eqloud.html

References

Richard P. McCall, "Earplugs and the NRR", TPT, Vol. 44, # 9, Dec. 2006, p. 580.

Albert A. Bartlett, "Logarithmic Scales: A Useful Example," TPT, Vol. 41, # 1, p. 16 (Jan. 2003).

C.T. Tindle, "Decibels Made Easy", TPT, Vol. 34, # 5, May 1996, p. 304.

Thomas D. Rossing, "Letters: 120 Decibels!" TPT, Vol. 27, # 9, p. 644, (December 1989).

Thomas D. Rossing, "Letters: 106 Decibels!" TPT, Vol. 26, # 5, p. 264, (May 1988).

"How Physics Is Used to Repel Deer and Fleas", TPT, Vol. 24, # 8, Nov. 1986, p. 503.

Robert Johns, "Musical String Vibrations", TPT, Vol. 15, # 3, Mar. 1977, p. 145.

Hugh Haggerty, "Sound Intensity and Good Health", TPT, Vol. 12, # 7, Oct. 1974, p. 421.

Sukhbir Mahajan, Michael Shea, D. L. Robinson, and Dave Mayhes, "Environmental Noise: An Undergraduate Research Project", AJP, Vol. 45, # 10, Oct. 1977, p. 987.

Sh- 3: Freier and Anderson, A Demonstration Handbook for Physics.

W- 055: "Hearing and Seeing Waves," DICK and RAE Physics Demo Notebook.

W- 085: "Oscillator and Oscilloscope," DICK and RAE Physics Demo Notebook.

W- 090: "Sound Level Mater," DICK and RAE Physics Demo Notebook.

1.45: Jearl Walker, "Getting Sick From Infrasound," The Flying Circus of Physics with Answers.

Ron Hipschman, "Hearing Range," Exploratorium Cookbook III, p. 193.1 - 193.4.

Tom Petruzzellis, "Sound Pressure," Electronic Sensors for the Evil Genius, p. 3.

Mail Questions and Comments to: Dale Stille