Standing Sound Waves - Reflection

Purpose

To demonstrate the origin of standing waves from one source and its reflection.

Equipment

Audio oscillator, small speaker, plane reflector and microphone on optical rail, audio amplifier, and dual trace oscilloscope.

Setup Time

10 min.

Images

h3-02

Description

A loudspeaker is driven at about 3000 Hz by a sine wave oscillation which is displayed on the top trace of the oscilloscope. The standing wave pattern, created by the sound from the speaker and the wave reflected off the flat metal plate, is picked up by a microphone sliding along the optical rail and displayed on the lower trace of the oscilloscope. ◙

References

Robert R. Meijer, Demonstrations on Standing Sound Waves, AJP 16, 360, (1948). ◙Francis W. Sears, Measurement of the Wavelength of Sound Wave, TPT 3, 79, (1965). ◙S. S. Lesty, A Method for Measuring the Sound Wavelength in Gases, AJP 31, 996-98, (1963). ◙J. Rekveld, On the Teaching of "Stand Waves," AJP 26, 159-163, (1958). ◙Directions For Use of Small Speaker, Leybold Heraeus 58006.