General Physics II Laboratory
The purpose of this lab was to find the measurement of the length of how long it takes for a sound to flow in a 1 meter-long tube within 5% error. The technique is to record the time of the echo sound made by snapping fingers. A microphone attached to the computer would be placed at the tube’s opening to determine the speed of sound at room temperature. Once the fingers were snapped at the opening, they created the sound, which traveled to the end of the tube back and forth. In addition, the microphone would collect the sound and transfer that information into the computer. After bouncing off from the closed end, the sound would hit the microphone; the computer would displace a graph, which shows the initial sound and the echo. The speed of sound would be determined by using the round-trip time and the length of the tube.
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A student was tasked to click ‘collect’ to start data collecting when another student snapped the fingers to make the sound. The sound would stimulate the interface to start collecting data. If the run is successful, the graph would display a series of vibrations clearly. Students clicked the ‘Examine’ button, and used the mouse to determine the time interval between the initial vibration and the final vibration. This procedure was done five times to determine the average of the speed of sound. The data was analyzed into the data table:
Data & Results:
Length of tube | 1.22m |
Temperature of room | 24 degrees C |
Trial | Total travel time(s)= t2-t1 | T1 | T2 |
1 | 0.0073 | 0.0123 | 0.0196 |
2 | 0.0072 | 0.0197 | 0.0269 |
3 | 0.0076 | 0.0097 | 0.0173 |
4 | 0.0073 | 0.0260 | 0.0333 |
5 | 0.0070 | 0.0249 | 0.0319 |
Average | 0.00728 | | |
% error = (true value – experimental value)/(true value)
=(346.1-335.2)(346.1) *(100%) = 3.149%
True value | Experimental Value | % Error |
346.1 | 335.2 | 3.149% |
I discovered that the true value was 346.1 because at 0 degrees Celsius, it was supposed to be at 331.5. In the experiment room temperature was 24 degrees Celsius, so I calculated by multiplying 24 by 0.607 and then I used the result to add it with 331.5. The experimental value found was 335.2. I calculated the percent error by subtracting the true value with the experimental value and then divide it with the true value and then multiply by 100%. My percent error in the whole experiment came out to be 3.149%. The experiment came out to be successful in the end and the reasoning was that the result was under 5% error and was close to the true value. The experiment proved that fluctuation in temperature has an effect on the speed of sound. The distance used to calculate the speed of sound was doubled because the distance of sound traveled from the end of the tube back to the opening. The experiment was done and repeated many times to make certain of the microphone’s consistence. Speed of sound was not an easy task to do but this experiment proved that speed of sound can be affected by changes in temperatures.