AAPT Logo
TPT Logo
 
   
 

The Physics Teacher -- October 2006 -- Volume 44, Issue 7, pp. 440

Doppler Football

Michael J. Ruiz and Jeremy Abee

University of North Carolina at Asheville, Asheville, NC

Full Text: Read Online (HTML) | Download PDF FREE | View Cart
In this paper we present a design for a Doppler football. The classic Doppler ball uses a piezo buzzer and 9-V battery inside a foam ball. In our Doppler football, the sound level is enhanced by directing the 2.8-kHz tone of the buzzer through a hollow cylinder to one end of the football, with an on-off switch placed at the other end. We discuss our device within the historical context of Doppler demonstrations that have evolved over the many decades since Doppler's discovery.

© 2006 American Association of Physics Teachers

KEYWORDS and PACS

Keywords

physics education, Doppler effect, educational aids, piezoelectric devices, acoustic waves, history, reflection, echo

PACS

  • 01.40.jh

    Inservice training

  • 01.50.My

    Demonstration experiments and apparatus

  • 43.38.+n

    Transduction; acoustical devices for the generation and reproduction of sound

History
Online Sep 2006

PUBLICATION DATA

ISSN

0031-921X (print)  

Publisher

$abstract.society.value is a Member of CrossRef American Association of Physics Teachers

ARTICLE DATA

Digital Object Identifier
http://dx.doi.org/10.1119/1.2353587

  1. A. Roguin, "Christian Johann Doppler: The man behind the effect," Brit. J. Radiol. 75, 615 (2002).
  2. Craig F. Bohren, What Light Through Yonder Window Breaks? More Experiments in Atmospheric Physics (Wiley, New York, 1991). The musicians didn't believe the effect would occur since the noise of a passing train does not change. However, noise is a mixture of many frequencies, so the effect is camouflaged.
  3. For an approaching train at 60 km/h (40 mi/h) [approximate] 20 m/s with the speed of sound u = 340 m/s, the Doppler-shifted frequency is

    [dformula f = f[sub s]((u/(u - v[sub s]))) = f[sub s](340/320) = (17/16)f[sub s].]

    A pitch ratio of 17/16 is approximately the 12th root of two, which indicates a half-step (semitone).

  4. John F. Koser, "Doing the Doppler: How to drive this concept home," Sci. Teach. 43, 40 (Sept. 1990).
  5. J.W.S. Rayleigh, The Theory of Sound, 2nd ed. (Dover Publications, New York, 1945), pp. 154–156. The first edition of Lord Rayleigh's book appeared in 1877 and the second edition was first published in 1894.
  6. Francis E. Fox, "Demonstration of the Doppler effect," Am. J. Phys. 12, 228–229 (Aug. 1944).
  7. O. Perrine, "The Doppler and echo Doppler effect," Am. J. Phys. 12, 23–28 (Feb. 1944).
  8. William E. Dibble, "A pedagogical note on the Doppler-effect formulas," Phys. Teach. 38, 362–363 (Sept. 2000)
    Robert Alt and Sam Wiley, "A generalized wave diagram for moving sources," Phys. Teach. 42, 526–527 (Dec. 2004)., Also see Bernhard Rothenstein, "Teaching the Doppler shift using a machine gun analogy," Phys. Teach. 39, 468–469 (Nov. 2001); and, Daniel Hoyt, "A different viewpoint on Doppler-effect calculations," Phys. Teach. 40, 14–16 (Jan. 2002).
  9. For two examples spanning 40 years, see Hans Weltin, "Demonstration of the Doppler effect," Am. J. Phys. 29, 713–714 (Oct. 1961) and, Marcelo M. F. Saba and Rafael Antônio da S. Rosa, "The Doppler effect of a sound source moving in a circle," Phys. Teach. 41, 89–91 (Feb. 2003).
  10. Harry E. Stockman, "Demonstration of the Doppler effect," Am. J. Phys. 30, 307–308 (April 1962)
    Paul Doherty and Don Rathjen, The Exploratorium Science Snackbook (Exploratorium Store, San Francisco, 1991).
  11. Frank S. Crawford, "Simple demonstration of Doppler effect, interference, and radiation resistance using a sonalert," Am. J. Phys. 41, 727–730 (May 1973).
  12. Ian Firth, "Doppler with a sounding tennis ball," Phys. Educ. 9, 63 (Jan. 1974).
  13. George Barnes, "A Doppler experiment," Am. J. Phys. 42, 905–909 (Oct. 1974).
  14. H. Richard Crane, "The Doppler ball: A novel use of the piezo-electric effect," Phys. Teach. 26, 120–121 (Feb. 1988).
  15. Dee Drake, "Doppler ball effects," Sci. Teach. 58, 62 (Feb. 1991). A Nerf football is recommended.
  16. A spherical Doppler foam ball is available from Arbor Scientific, http://www.arborsci.com (Product ID: P7-7120).


Close

Your Recent History Recent History Help

Recently Viewed

  1. Doppler Football
  2. Creating a Virtual Ripple Tank in Microsoft Word
  3. Rocket Propulsion with Sparklers
  4. What Was I Thinking?
  5. Why Do We Feel Weightless in Free Fall?

AAPT on:

close