From: Mike Ugawa (mugawa@quark.sfsu.edu)
Date: Thu Nov 11 1999 - 13:15:55 PST
From: Mike Ugawa <mugawa@quark.sfsu.edu> Message-Id: <199911112115.NAA27437@quark.sfsu.edu> Subject: Resonance Demo Date: Thu, 11 Nov 1999 13:15:55 -0800 (PST)
I need help in getting printed plans for making the following resonance
demo, which I saw at one of the conferences/workshops I attended in the
last two years (I can't remember exactly where or when):
The apparatus consists of a wooden box about the size of two shoe boxes
laid end-to-end. There is a speaker (possibly two) inside and the box is
divided into (3 or 4 ?) chambers. There is an opening or two facing
upward. There are two supports on which is placed a piece of (plate) glass
(about 2 feet long x 4-6 inches wide). The supports hold the glass about
1-2 inches above the box. As the frequency of the sound is adjusted, a
standing wave can clearly be seen to develop in the glass, and at the
right frequency the glass shatters.
This is more dramatic than the usual approach with speakers and a beaker
or wine glass. It is also easier to setup--no microphone and oscilloscope
are needed to tune the frequency. The sound does not have to be so loud as
to hurt the ears of those in the front row of the class.
If you have plans for this (including what kind of glass to use, which
is critical) or can refer me to someone who might be able to help, please
let me know.
Thanks.
Mike Ugawa
St. Ignatius College Prep, San Francisco
mugawa@quark.sfsu.edu
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