Code Number: 3B60.20
Demo Title: Beats - Oscilloscope
Condition: Good
Principle: Constructive & Destructive, Interference of Sound Waves
Area of Study: Oscillations & Acoustics
Equipment:
PA Amplifier, Frequency meters (2), Wave generators, Tektronix 2235 Oscilloscopes (2), Speakers (pair, large), Scaler-Timer (Nucleus).
Procedure:
The setup with the two generators and one or two oscilloscopes will show wave interference and addition but will not be audible. The setup with the speakers is an audible counterpart of the above demo. Input the generators into the amplifier and plug the amplifier into one speaker. As the two systems are operated together you will hear the interference pattern. The frequency counter is just so you are sure at what frequency you are operating, if needed with non-digital generators.
References:
- Alessio Ganci, Salvatore Ganci, "The Simplest Demonstration on Acoustic Beats", TPT, Vol. 53, # 1, Jan. 2015, p. 32.
- Ronald Newburgh, "An Alternative Approach to Explaining Beats", TPT, Vol. 44, # 2, Feb. 2006, p. 86.
- Brian Andersson and Matthew Dykoski. "Demonstrating Beats with Springs and a Cart", TPT, Vol. 43, # 8, p. 490, November 2005.
- Derrick E. Boucher, "A Visual and Acoustic Demonstration of Beats and Interference", TPT, Vol. 37, # 3, p. 177, March 1999.
- Frazier Worth, "Beats: Video Monitors and Cameras", TPT, Vol. 34, # 6, p. 374, Sept. 1996.
- Robert W. Schramm, "Using a Stereo Tape Recorder as a Demonstration Device", TPT, Vol. 12, # 3, March 1974, p. 172.
- S. H. Vegors, Jr., "Beats and interference: A classroom demonstration", AJP, Vol. 43, #12, Dec. 1975, p. 1103.
- Si- 4: Freier and Anderson, A Demonstration Handbook for Physics.
- W-115: "Slinky Simulator - Coiled Spring", DICK and RAE Physics Demo Notebook.
- W- 315: "Beats with a Drift", DICK and RAE Physics Demo Notebook.
- Paul Gluck, "You Can Illustrate Beats Without the Usual Tuning Forks", Physics Education, Vol. 39, # 3, May 2004, p. 241.
- Ron Hipschman, "Walking Beats", Exploratorium Cookbook, p. 117.1 - 117.2.
- W. Bolton, "Beats", Book 2 - Waves and Particles, Physics Experiments and Projects, 1968, p. 66-67.