Lab 5: Introduction to Sound (5) s

Purpose:

In this lab we will examine the periodic nature of sound waves by analyzing sound of human voice and tuning forks.



Method:

We will be using logger pro and an attach microphone to obtain a graph of sound pressure vs. time to analyze the nature of sound waves.

Figure 1: Microphone recording sound wave from tuning fork.

Data and Analysis:

Figure 2: Sound Pressure vs. Time (human) 

• Sound wave is periodic as evidence by the sinusoidal behavior of the graph.
• There are 7 waves in the data collected in Figure 2, we designate the gap between two crest to be one wave.
• The time frame in Figure 2 is comparable to a flash of eye.
• T = 0.0038 ± 0.0001 s, the period is define by the time it takes to complete one cycle.
• ƒ = 262 ± 7.59 Hz,  ƒ  = 1/ T  
• λ = 1.30 ± 0.039 m,  λ = v / f, the length is comparable to a meter stick.
• Amplitude A = 2.718 ± 0.2 W, we took the average of the two different peak to determine the amplitude of the wave. 

Figure 3: Sound Pressure vs. Time (human, t = 0.3)

• All characteristic of Figure 3 will be similar to Figure 2 except the time frame will be ten times as long.

Figure 4: Sound Pressure vs. Time (human) 

• There are 3 waves in Figure 4.
• ƒ = 129 ± 5.81 Hz
• T = 0.01132 ± 0.002 s 
• λ = 2.63 ± 0.057 m
• A = 0.14 ± 0.02 m
• The sound wave in Figure 4 has a lower frequency and smaller amplitude than that of Figure 2.

Figure 5: Sound Pressure vs. Time (tuning fork) 

• The graph made by tuning fork is much smoother due its ability to produce sound waves in a single set of frequency. 

Figure 6: Sound Pressure vs. Time (tuning fork)

• The loudness of a frequency is determined by the amplitude of the wave, thus Figure 6 has a lower amplitude than Figure 5.

Conclusion:

In this lab we have analyze the property of the sound wave graphically. We find that sound waves are generally periodic as shown in the repetitive pattern. And the intensity and loudness of sound is directly proportional to the amplitude of the wave. We also discover that single frequency sound wave act as a sinusoidal wave. This proves that human voice does not produce one frequency but multiple while talking.