Others might joke about Thag and Oona, but I don't see this as an unreasonable request. Most common sewing threads will be totally unsuitable because they have a built-in twist. If you try to hang a heavy weight from a common thread, the weight is likely to spin and spin until the untwisted thread breaks. There is also the matter of getting the correct elasticity (don't want the mass bouncing) and strength (don't want it hitting the floor). For long-term observations you don't want the thread to twist or change length when the humidity changes, either. Presumably the reviewer would like you to provide a reference to a source of thread or string that is suitable for your application so that the reader can set up the experiment for himself or herself.
These properties of thread are probably precisely why Cavendish resorted to a difficult-to-make quartz fiber for his balance.
Vickie Frohne
(who makes thread Oona's way, and it's not that easy)
-----Original Message-----
From: Forum for Physics Educators [mailto:PHYS-L@list1.ucc.nau.edu]On
Behalf Of Michael J. Moloney
Sent: Friday, October 01, 2004 9:01 AM
To: PHYS-L@LISTS.NAU.EDU
Subject: vibrating bar supported by light string to reduce damping
A paper of mine on bar vibrations is being reviewed, and the reviewer
would like me to provide a reference for light string (or sewing thread)
to markedly reduce damping and permit one to observe the vibrations over
an extended time (many seconds).
This technique was probably used a century or more ago, but my searches
so far have not turned up anything. I do recall reading about using
light threads to support a long wire and bringing the threads close to
the ear so one could hear quite rich tones from the long wire. That may
have been in The Physics Teacher.
If you know of a reference (maybe even a recent TPT one) please let me
know off-line.
Thanks a lot
Mike
--
Mike Moloney, Physics & Optical Engineering Department
Rose-Hulman Inst of Tech, 812 877 8302
moloney@rose-hulman.edu http://www.rose-hulman.edu/~moloney