Later I got bored and built a much longer version of the same whistle. This whistle was built without the tone holes, but I was still able to get as many as 10 or 15 tones out of it based solely on the amount of wind pushed through it. There were 3 dominant tones that were the easiest to achieve and provided the purest sounding tones. They were an F, C, and A. The Major triad of F. Seeing as how these notes bore such a strong relationship to one another, I decided these had to be the resonant frequencies of the tube.

Then after my presentation being postponed by another week, I decided to see if i could build an even bigger one. This time I would alter the diameter as well as the length. To me this was the true experiment, because my fascination with pipe organs is what led me to try to build whistles out of PVC in the first place. Pipe organs use pipes of all sizes and lengths altering their tuning by various different means. lengthening or widening the fipple (the square hole at the bottom of the pipe) alters the tone as well as its length and diameter. I had no idea however what differences is the amount of air being blown through would achieve. As it turned out, more air meant a higher note within the pipe's natural resonant frequencies. Less air meant a lower note. With the third pipe, it was difficult to provide the necessary airflow with only my lungs, but it illustrated my point nicely.

Thanks to Dan Hemingson for the videos.