The physics of sound is often studied in introductory physics class experiments involving a tube of resonating air. In typical setups, pistons control the length of a cylindrical space or a microphone is moved within a tube.1 While these activities are useful and can be made very quantitative, they don't directly demonstrate the sounds that are most familiar to students, such as human voices and musical instruments. Fortunately, several sound spectrum analysis programs are available that can bridge this gap.2
REFERENCES
1.
See, for example,
Vincent
Santarelli
et al., “Standing waves in a mailing tube
,” Phys. Teach.
31
, 557
(1993
), andJames A.
Warden
, “Measuring the speed of sound without plumbing
,” Phys. Teach.
43
, 308
(2005
).2.
Two software programs were used for this report: “Audioscope,” which is available at http://www.arborsci.com, and “Test Tone Generator,” which can be downloaded from various websites. Similar software is discussed at http://www.visualizationsoftware.com/gram/gramdl.html, http://www.pasco.com, http://www.faberacoustical.com/SignalScope/, http://www.adobe.com/products/audition/overview.html, and elsewhere on the web.
3.
For discussions of human voice spectrum patterns, see
Johan
Sundberg
, “The acoustics of the singing voice
,” Sci. Am.
236
, 82
(March 1977
), andMichael F.
Dorman
and Blake S.
Wilson
, “The design and function of cochlear implants
,” Am. Sci.
92
, 436
–445
(2004
).4.
For a description of a very quantitative approach to this kind of experiment, see
Brian
Martin
, “Measuring the speed of sound—Variation on a familiar theme
,” Phys. Teach.
39
, 424
(2001
).
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© 2007 American Association of Physics Teachers.
2007
American Association of Physics Teachers
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