Introduction to Sound

Objective: Explore sound waves.

Equipment:

• Logger Pro with Microphone
• Computer
• Tuning fork

 We set up logger Pro with a microphone to record sound.

To get a sample we made noise into the speaker (saying "aaaaaaaaaa") and set the ample rate high and the sample time very low ( about 0.5 seconds)

In order to study this sample more closely we zoomed in on a portion of the data.

Examining this graph it is obvious that it is not sinusoidal but it is periodic (it repeats after a certain amount of time)
     We estimated about 23 waves in this sample. We did this by counting the peaks in the duration of time. This was difficult because the sample time was very quick like the way an hour can pass in the blink of an eye when your doing a difficult physics problem.
     We measured the period by taking the difference in time recorded between two adjacent peaks. This came out to be 0.00123 seconds. Since frequency is the inverse of period the frequency was shown to be 813 Hz.

     Using the above calculations (and assuming the speed of sound to be 340 meters per second) the wavelength is 0.418 m. To find the amplitude we used two adjacent peaks and found the maximum and minimum and took the average. This came out to be 0.384 m. If we were to get a longer sample the data would be the same some values might vary slightly simple because the sample would give us more to work with so we might be able to get a more accurate average of values.
     This was repeated with my lab partner speaking into the microphone. His values were different he had a lower frequency which led to a shorter wavelengrh but the data was very similar. This is the second data set:

     We then used a tuning fork and recorded the sound on Logger Pro. We struck the fork on the sole of a shoe as to not damage the fork The result was a very smooth looking sinusoidal wave.
     Using the same methods as before the following data was collected.

• Period: 0.00994 s
• Frequency: 101 Hz
•  Wavelength: 3.38 m
• Amplitude: 4.55 cm

To test what would happen if the fork was struck with different intensity we ran a second trial with the tuning fork. We had predicted it would only change the amplitude.
   

 The fork was struck again as to resonate with a different amplitude and this was the result:

• Period: 0.00982 s
• Frequency: 102 Hz
• Wavelength: 3.34 m
• Amplitude: 2.00 cm

    The prediction was correct all the data (excluding the amplitude) was off by an amount of a few figures on the order of the smallest significant figure (experimental error) with the exception of the amplitude.