The Experiment - The Sound

What is this?How is it made?The experimentWhy does it sing?

The pipe sings!
(Or, more precisely, howls.)

The cold part of the pipe slowly heats up, the sound changes and finally vanishes.

We could dip the pipe in Dewar again and cool its open end.

But let us leave the pipe to heat up to the room temperature and meanwhile try to explain how it can produce sound if nothing moves in it. Any suggestions?

The pipe sings
Listen! Listen to the .wav (65 k).

How the pipe produces sound? >>

Two notes Listen to three complete recordings:

  • piscal3-t.wav (775 k) - complete recording (the upper sound is a short part of it),
  • piscal1-t.wav (577 k) - another complete recording; the changing of the sound amplitude and pitch can be clearly heard; clicking of the camera is (unfortunately) also heard,
  • piscal2-t.wav (810 k) - ...and another complete recording.
Diagrams Take a look at the diagrams of the recordings, their frequency spectra and the changing of the frequency and amplitude of the sound with time.
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Last revised: Jan.31. 2001, © Andrej