Introduction to Sound

Purpose
     The purpose of this lab is to be able to analyze the different sound wave. This lab will also make us to be able to recognize the effect of pitch and volume to the graph of the sound waves.

Experiment
    The setup of experiment is as follow:

Experiment for the part using tuning fork

The setup of the first one is by one person saying "AAAAAAAAAAAA" and then the sound waves is recorded as follow:

figure 1. The sound wave from my lab partner

1. The wave appears to be periodic since the shape repeats as time goes.
2. The waves shown in the sample above has 7 waves. This can be determined by counting the number of the same shape of the waves.
3. The probe only took 0.03 seconds to get this data. It is like 1/10th of a google search.
4. The period of the cycle appears to be 0.0038 s. This can be determined by looking at the time it takes for 1 cycle to complete
5. The frequency on the sample appears to be 262 Hz by using the formula f = 1/T
6. By using the formula lambda =  velocity  /  frequency , the wavelength is calculated to be 1.298 m.
7. The amplitude of these waves appears to be 2.468. This is obtained by taking the average of the smallest amplitude and the largest amplitude in the waves.
8. If the graph is 10 times longer, the only things that changes is the number of waves obtained

figure 1h.  The graph when time taken is 0.3seconds

figure 2. The graph of my other lab partner

1. The number of waves in this sample is only about 4 lower than sample 1
2. The frequency of this sample is 133Hz lower than sample 1
3. The period of this sample is 0.00752s greater than sample 1
4. The wavelength for this sample appears to be 2.56m
5. The result makes sense since sample 2 is done by a male student which have lower pitch while the first one is conducted by a female student which have a high pitch.This makes some difference in the frequency, wavelength and period in the sample.                                          

After the human voice was used, a tuning fork is now used and the graph was taken

figure 3. Graph of the sound waves of tuning fork

Compare to the human voice graph in figure 1 and 2, the tuning fork has a perfect sinusoidal waves. This happens because tuning fork is set to have only one frequency. In human voices, there will be some different frequencies and the one that is been captured is the resonant frequencies of our voices. 

When the volume or intensity of the sound is lower than the previous, the only thing it will change is the amplitude as shown in the picture below:

Figure 3h. Graph of tuning fork with lower volume

As seen in the graphs, the only thing that is different is the amplitude. The frequency, period and wavelength is the same.

Discussion

           Through this lab, we know that sound waves is a periodic waves. Moreover if there only one frequency, like in tuning fork, it will show as a perfect sinusoidal waves. In human voices, even the simplest sound have more than one frequencies and it is shown in the graph that it is a resonant frequency that is being recorded. Furthermore we know some changes that could affect the sound waves. The pitch of a person change the frequency, wavelength and period, while the change in volume or intensity of the sound only changes the amplitude of the waves