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Using a Bottle as Helmholtz Resonator

Some bottles sound more readily than others. I enjoy collecting old remedy or medicine bottles on walks through meadows. Look for bottles of various sizes. Practice sounding them as I show above.

The first Spectrum Class was held on Nov. 01/05. I, Glenn Bowie, Mrs Anderson, and Tyler Knott used a team-teaching appoach. As an introduction, I sat on the classroom floor with a group of eighteen 4th/5th grade students. I explained the first principles of Helmholtz resonator. Tyler Knott used the instructor's pc, a microphone, a speaker and power amplifier, and an overhead projector to show sound wave groups being recorded with aide of WavePad. I blew air across the neck of a bottle to generate the sounds.

In the Nov. 29/05 class, Mrs. Anderson used this image to explain meaning of the term "embouchure".

With practice, the amount of water added to the bottle was adjusted to give a fundamental frequency approximately equal to Middle C, which is 261.626 cycles/second, or Hertz, Hz.

A program called Gram.exe was used to analyze sound bottle01.wav, with the following results.

Mrs. Anderson listened to the bottle's Middle C sounds, then sang the notes of an octave beginning with doh -- at 262 Hz. Analysis of her upper doh -- note showed it was at 524 Hz.

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