Standing Sound Waves Lab Report
Purpose: The purpose of this experiment was to determine the speed of sound
from an interference pattern produced by two speakers emitting a tone of constant
Data: Printout of spreadsheet. Your data table should include columns for m,
m − 1/2, ∆y, y, θ, and sin θ. Make sure that you also include in your data section
the frequency of the emitted sound, the temperature, the distance along the
centerline (L), and the distance between two speakers (d).
Graphs: One graph showing m − 1/2 vs sin θ. Fit to a straight line.
1. Use the temperature to calculate the speed of sound in air. The formula for
this calculation is v = v◦ 1 + 273C C , where v◦ = 331 m/sec.
2. Perpendicular distance from the centerline to the m = 3 quiet spot, i.e., y for
m = 3.
3. θ for the quiet spot corresponding to m = 3.
4. sin θ for the quiet spot corresponding to m = 3.
5. Wavelength of the sound based on the slope of the graph.
6. Speed of sound based on the wavelength and frequency.
7. Percent diﬀerence between the two calculated speeds of sound.
1. What was the path diﬀerence between a wave traveling from the left speaker
and a wave traveling from the right speaker that meet at the farthest quiet
spot that you measured? Express you answer symbolically in terms of the
wavelength (for example, 2λ, etc.).
2. What is the path diﬀerence between a wave traveling from the left speaker
and a wave traveling from the right speaker that meet at the centerline?
Conclusions: See the handout Writing Lab Reports in Physics to see what is
needed in the Conclusion section.