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Gr. 9 Sc. Fair Project: Update



To All:

I've been spending most of my time lately on the Bioacoustics Mailing List.
My questions about elephant infrasound have brought out the information that
the reported frequencies are even lower than I thought.  Elephants are now
reported to produce vocalizations as low as 14 Hz.

On the Bioacoustics List, the majority of those writing seem to agree that
the best model to explain this is to view the elephant's lungs as a Helmholt
resonator.  This is similar to making a sound by blowing across a pop
bottle.  The volume of the pop bottle is the only factor which must be
considered to find the lowest frequencies.  Calculations with this model
seem to give resonable results for elephants and for blue whales.  I hope to
eventually find a way to extend the results to hadrosaurs.

Does anyone know of other living animals who produce infrasound?  Girraffs?
Whistling Swans?  Where can I find data on lung capacity and neck lengths?

The other work on my project happens on Wed. nights when I meet with a local
ham radio club where an electronics technician is leading me through the
construction of a frequency generator and supporting electronic components.
By having some of my own toys, I hope to be able to make more measurements
on my parasaurolophus model without having to get outside help.  The
technician is also loaning me an oscilloscope to take to the Canada-Wide
Science Fair.

I'm also continuing with the reading that many of you have recommended.  I
think I'm finally figuring out what acoustic impedance is!

I'll keep you posted on developments.

Thanks again,
Della Drury
drury@telusplanet.net