Bnibling/Acoustic Lab
Harmonics
Barrett Nibling
December 4th, 2007
Contents |
Abstract
This experiment dealt with the unique frequency patterns, known as harmonics, that sound produces in a resonator. Using white noise generated by a computer and transmitted through a speaker into our resonant cavity, a pipe, and at the other end was placed a microphone to record the outgoing frequencies. Using the geometry of the pipe and derived equations, theoretical values were calculated were calculated and compared to the measured values. The experimental data was within <insert %>% of the theoretical data.
List of Figures
[1]Schematic of Harmonics Apparatus
Introduction
Sound produces unique frequency patterns when travelling through a resonant cavity, such as a tube, known as harmonics. These patterns depend on the frequencies sent into the body, the material, but more importantly the geometry of the structure. A computer was used to produce sound waves in the form of white noise through a speaker into one end of the cavity and by placing a microphone recording the frequency patterns on the other end, we could record the data on the computer for analysis. The computer software represents the data as a plot and the patterns on a graph shows the resonant peaks which occured in the cavity. These peaks can then be compared to expected peaks by using previously derived equations for the tubes we used. The derived peaks and the expected peaks were then compared and were found to agree within experimental error.
Theory
Procedure
Results
Color | θdiff (degrees) | λ (nm) | Error (nm) | Published λ (nm) | |
---|---|---|---|---|---|
Purple | 15.6 | 448.0 | 2.0 | 447.148 | |
Teal | 16.4 | 470.3 | 2.0 | 471.314 | |
Green | 17.2 | 492.6 | 2.0 | 492.193 | |
Green | 17.5 | 500.9 | 2.0 | 501.567 | |
Yellow//Orange | 20.7 | 588.8 | 2.0 | 587.562 | |
Red | 23.6 | 666.9 | 2.0 | 667.815 | |
Dim Red | 25.1 | 706.7 | 1.9 | ??? |
Error Analysis
Then the total error is the sum of the two partial derivatives added in quadrature,
Conclusion
References
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