Exploring Sound Amplitude in Varying PVC Pipe Lengths

1036 Words3 Pages

The purpose of this experiment was to determine whether if the sound is affected when it travels through different length pipes. The method used to do this experiment was created by using 5 different PVC pipes in the lengths of 10, 20, 30, 40, and 50 centimeters. Then, using a tuning fork, sound will be produced on one end of the PVC pipe and measured with a decimeter on the other end. This experiment was recorded using 5 trials for each independent level and the average decibels (dB) for each pipe length were recorded.
The results collected during this investigation were as follows: 68.4 dB for the 10 cm pipe, 69.8 dB for the 20 cm pipe, 79 dB for the 30 cm pipe, 84.2 dB for the 40 cm pipe, and 84.2 dB for the 50 cm pipe. The hypothesis states: if the length of the PVC pipes were to increase and the frequency used in this experiment remained the same, then the sound produced from the pipe will have a lower amplitude each time. According …show more content…

It was proposed that if the length of the PVC pipes were to increase, then the sound produced will have a lower amplitude each time because the sound will lose energy as it continues in the pipe for a certain amount of time. However, the data actually showed that with every increase in pipe length, the amplitude got louder as well, thus refuting the hypothesis. These results made sense because what was created inside the PVC pipes was a standing still sound wave, or a resonance wave. These kinds of waves have certain locations on its wavelength in order for the change in sound to be heard, which it usually half a wavelength. With this, the tuning fork is 83.3Hz and a usual wavelength is about 300Hz, 300/83.3 = 3.6 meters, which is about 4 meters (half = 2 meters). So for the change in sound to be heard, the pipes had to be about 2 meters in change according to the frequency of the tuning

Open Document