PURPOSE: To produce the interference of sound from two identical sources.
DESCRIPTION: A long bar has a pivot in the middle and two loudspeakers at each end, as shown in the above photo at right. An oscillator sends a signal to both loudspeakers. The bar is slowly rotated and the interference of alternating maxima and minima in the intensity pattern is heard by the students at thier seats, as shown in the photo at left. The nodal and antinodal lines heard by the students will show the relationship between the wavelength, the source separation and the distance to thier respective seats.
EQUIPMENT: Two speakers on a pivot bar, function generator, as photographed.
SETUP TIME: 1/2 hour.
Updated by Jun Qi in 4/5/2000