Date: Thu, 09 Dec 2004 10:12:11 -0500

Author: sampere

Subject: Re: Tuning Forks

Post:

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A few weeks ago, William Fry (U of Wisc.) gave a phenomenal colloquium
here on the physics of the violin. He described all the parts, why they
are shaped as they are, show the thickness contours, what parts
contribute to low frequencies, high frequencies, etc. It really was a
great talk. I video taped it on DV. Now I need to transfer it to DVD.
Maybe I'll bring a couple to the summer meeting - hey, we could show it
in the Resource Room. I'll ask him for permission first, of course, but
he seemed real easy going.

Steve, do you know him? Do you have a tape of his violin talk already?

Sam

Steve Wonnell wrote:

>I thought someone else would tune in to bring up the question of whether
>there is any similarity to this question and the question of why piano
>strings always come in two (or more) per hammer (or key). That question
>has been answered pretty well. When a pair of piano strings are first
>struck together with a single hammer, they vibrate together for only a
>brief period of time (the transient mode), and very quickly move to a
>pattern of vibrating out of phase with each other (the sustain mode).
>In the latter mode, each string's vibration continues far longer than
>either would if struck individually.
>
>The vibration of a single string, individually mounted, dampens quickly
>due to energy loss at the bridges holding the string. When two strings
>are mounted together, side by side, on the same bridge, then the energy
>"loss" at a given bridge is "gained" by the string moving in opposite
>phase. This results in a long, sustained note.
>
>Twenty some years ago, Gabriel Weinreich wrote an article summarizing
>these findings in Scientific American.
>
>Note that two tines of the tuning fork move in opposition.
>I'd bet that there's an similar energy transfer mechanism at work
>at the junction of the tines.
>
>Steve W.
>
>
>On Thu, 9 Dec 2004, Thomas J Senior wrote:
>
>
>
>>Date: Thu, 09 Dec 2004 06:44:44 -0600
>>From: Thomas J Senior
>>Reply-To: tap-l@listproc.appstate.edu
>>To: tap-l@listproc.appstate.edu
>>Subject: Re: Tuning Forks
>>
>>Ann,
>> Convenience of construction. Wind chime type tubes vibrate nicely,
>>but you have to hold them by a nodal point (22.4% of the length from
>>each end). In the tuning fork, the handle is attached to the nodal
>>point for the vibrations in the configuration, at least at the
>>fundimental frequency. I'd also hypothesize that it is easier to
>>construct given blacksmith type technologis. The tuning fork must be
>>several hundred years old.
>>
>>Tom
>>
>>Thomas J. Senior
>>New Trier High School
>>385 Winnetka Ave
>>Winnetka, IL 60093-4295
>>847-784-6739
>>
>>
>>>>>ahanks@pasco.com 12/08/04 1:22 PM >>>
>>>>>
>>>>>
>>Why do tuning forks have to be forks? Why 2 sides?
>>
>>Ann Hanks
>>PASCO
>>
>>
>>#####################################################################################
>>This e-mail message has been scanned for Viruses and Content by
>>NTTC's e-mail gateway.
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>>
>>
>>
>>
>
>
>************************************************************************
>Steven K. Wonnell
>Physics and Astronomy Department E-Mail: wonnell@pha.jhu.edu
>Johns Hopkins University Phone: (410) 516-4696, 516-5468
>3400 N. Charles Street Fax: (410) 516-7239
>Baltimore, MD 21218-2686 Office: 478 Bloomberg
>************************************************************************
>
>

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A few weeks ago, William Fry (U of Wisc.) gave a phenomenal colloquium
here on the physics of the violin.  He described all the parts, why
they are shaped as they are, show the thickness contours, what parts
contribute to low frequencies, high frequencies, etc.  It really was a
great talk.  I video taped it on DV.  Now I need to transfer it to
DVD.  Maybe I'll bring a couple to the summer meeting - hey, we could
show it in the Resource Room.  I'll ask him for permission first, of
course, but he seemed real easy going.



Steve, do you know him?  Do you have a tape of his violin talk already?



Sam



Steve Wonnell wrote:

cite="midPine.SOL.4.58.0412090856340.2043@eta.pha.jhu.edu">

I thought someone else would tune in to bring up the question of whether
there is any similarity to this question and the question of why piano
strings always come in two (or more) per hammer (or key). That question
has been answered pretty well. When a pair of piano strings are first
struck together with a single hammer, they vibrate together for only a
brief period of time (the transient mode), and very quickly move to a
pattern of vibrating out of phase with each other (the sustain mode).
In the latter mode, each string's vibration continues far longer than
either would if struck individually.

The vibration of a single string, individually mounted, dampens quickly
due to energy loss at the bridges holding the string. When two strings
are mounted together, side by side, on the same bridge, then the energy
"loss" at a given bridge is "gained" by the string moving in opposite
phase. This results in a long, sustained note.

Twenty some years ago, Gabriel Weinreich wrote an article summarizing
these findings in Scientific American.

Note that two tines of the tuning fork move in opposition.
I'd bet that there's an similar energy transfer mechanism at work
at the junction of the tines.

Steve W.


On Thu, 9 Dec 2004, Thomas J Senior wrote:



Date: Thu, 09 Dec 2004 06:44:44 -0600
From: Thomas J Senior <seniort@newtrier.k12.il.us>
Reply-To: tap-l@listproc.appstate.edu
To: tap-l@listproc.appstate.edu
Subject: Re: Tuning Forks

Ann,
Convenience of construction. Wind chime type tubes vibrate nicely,
but you have to hold them by a nodal point (22.4% of the length from
each end). In the tuning fork, the handle is attached to the nodal
point for the vibrations in the configuration, at least at the
fundimental frequency. I'd also hypothesize that it is easier to
construct given blacksmith type technologis. The tuning fork must be
several hundred years old.

Tom

Thomas J. Senior
New Trier High School
385 Winnetka Ave
Winnetka, IL 60093-4295
847-784-6739




ahanks@pasco.com 12/08/04 1:22 PM >>>




Why do tuning forks have to be forks? Why 2 sides?

Ann Hanks
PASCO


#####################################################################################
This e-mail message has been scanned for Viruses and Content by
NTTC's e-mail gateway.
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************************************************************************
Steven K. Wonnell
Physics and Astronomy Department E-Mail: wonnell@pha.jhu.edu
Johns Hopkins University Phone: (410) 516-4696, 516-5468
3400 N. Charles Street Fax: (410) 516-7239
Baltimore, MD 21218-2686 Office: 478 Bloomberg
************************************************************************





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From zeke_kossover@yahoo.com Thu Dec 9 10:12:02 2004

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