# Functional relationship of pressure and position(1d)

so today I started doing my research on oscillations in a course on advanced mechanics. The experiment was to mathematically model the speed of sound in air and experimentally prove the usability of the model. To keep it simple and pose my question as directly as possible, my professor told me to use the driving sound wave from the speaker in a open cylindrical tube. Further, the maxima of the voltage as read by the microphone(displayed by the oscilloscope) was to be considered as the peak(amplitude) of the pressure. What I am trying to establish is the functional relationship between pressure and position. I have a graph of voltage against position(attached), but I do not know what to fit the data points with. All your suggestions and help is hereby gratefully appreciated. Thank you in advance.

• Q1: What kind of function describes a wave? Q2: How does that relate to the fact that you've only plotted non-negative values? – user3823992 Oct 1 '14 at 21:03
• @user3823992 Well, it is a sinusoidal wave as generated by the speaker. I have the plot of pressure vs position, where are the negative values in those measurements? – GramCracker Oct 3 '14 at 14:53