Making a Woodwind instrument

7	For this experiment, you will need; A Cathode Ray Oscilliscope (CRO) A Signal Generator

Connect the CRO and signal generator according to the CRO manual, with the x-axis as the timebase and set the signal generator to produced a 50Hz signal.  Adjust the CRO settings until you can see a well formed sine wave on the screen.  Adjust the frequency of the signal generator.  How and why does the wave change?