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From: Martin Simon <msimon@physics.ucla.edu>
Date: 2009, October 19, 23:40:19 PDT
To: tap-l@lists.ncsu.edu
Subject: Re: [tap-l] Breaking a wine glass
Reply-To: tap-l@lists.ncsu.edu
We are having good success with a white wine glass
Wine Enthusiast® Reserve 11 1/2-Ounce White Wine (Set of 4)
<http://www.wineenthusiast.com/wine-enthusiast-reserve-white-wine- glasses-%28set-of-4%29.asp>
I pick them up at Bed Bath and Beyond
<http://www.bedbathandbeyond.com/product.asp? order_num=-1&SKU=16084360&RN=59&KSKU=116272>
though they change styles frequently and may not carry them forever.
When you get to the point that the straw jumps around wildly,
you just need enough amplitude, if your speaker and amp can
deliver it.
As others have done, we have a volunteer sing into a microphone
which we amplify and break the glass. For detection of resonance
we use a straw bouncing around, a strobed view of the glass top
or an oscilloscope.
We have tested a few people to see if they can break the glass
with their voice alone, unamplified. So far, none has done it
but we expect that it can be done. Below are some youtube videos
which purport to show people breaking glasses with their voice alone.
I'm interested in hearing about verified cases. The last link is to
the fellow who finally broke a glass on mythbusters. Apparently
his skill has improved.
<http://www.npr.org/templates/player/mediaPlayer.html? action=1&t=1&islist=false&id=104447724&m=104448429>
http://www.youtube.com/watch?v=eTWDEsGlPO8
http://www.youtube.com/watch?v=fbfjcEzFN2U
http://www.youtube.com/watch?v=CuIPpqlLTWU
http://www.youtube.com/watch?v=10lWpHyN0Ok
The high amplitude resonance is lower frequency
than the low amplitude resonance. This is a softening.
More details in The resonant excitation of a wineglass
using positive feedback with optical sensing
Kenneth D. Skeldon, Valerie J. Nadeau, and Christopher Adams
Am. J. Phys. 66 851 (1998)
Martin Simon
Bernard Cleyet wrote:
There are extensive threads with this subject on tap-l. I suggest searching there. One thing (nearly?) always common is the use of a microphone to detect the resonance. Important, because the object is nonlinear w/ amplitude (hardening, IIRC.)
bc observed several times performed by tapers.
p.s. adequate coupling (Z matching) of the driver to the chamber also discussed