This is a little demonstration of sound waves and pipes. This is just a pipe; it's open at both ends. Put the mouth piece on the end. I'll produce the fundamental frequency. Now as you know from the reading any pipe can produce not only the
fundamental but higher harmonics; so I'll produce a couple of harmonics. I'll start with the fundamental. Now we can turn this into a closed pipe also, a closed pipe has one end closed and the other end open. This will be the open end even though it has a
mouth piece it's still an open end. And I'll close off the other end with this mouse pad. And I want you to here the difference in the two tones from when the pipe is open to when the pipe is closed. We'll start with the pipe open again. This is the fundamental.
and now closed. You can hear the frequency go up, it actually goes up by an octave when the mouse pad is taken off.