[TheForge] Re: triangle bells/rebar

[Mike Spencer]

Andy g. quoth:

>> The stuff you learn early on holds a disproportionate place in your
>> memory.  I never trusted rebar after that.  Even if it *does* hold up
>> bridges, overpasses and aqueducts.
>
> Works great when surrounded by about a ton of concrete.
> Then you don't have to look at it, either.

*SPLORF!*

Now that I've picked myself up off the floor, sopped  up the spilled
coffee and wiped the monitor......

It occured to me that there are several other things to which that
would apply quite satisfactorily.  And maybe a couple of people, too.


Back on topic:  I have some brass tube -- leftover stock, I was told,
from a WW II contract at Acadia Gas Engine for bombsight parts -- that
rings melodiously when tossed into the air and struck.  But when I try
to hang a piece to make a chime, it varies between rather dull and
dead as lead except when hung on fine monofilament.  Which isn't too
useful because the monofilament chafes through real quick.  Tried
numerous cute little metal pins and widgets, nylon twine, leather.

But I have a vague recollection from high school physics that tubes
have weird vibration modes and harmonics.  Maybe I have to know
exactly where the nodal point(s) of the vibration are.

Say, maybe you could analyze the triangle gongs to determine where the
least-vibrating nodal point(s) is(are).  Um, lessee: magnetize one
just enough so that iron powder just barely kinda sorta sticks to
it. Very light coat of white paint.  Iron powder all over.  Ring it
and see where the iron powder falls off.  Those place are vibrating,
aren't nodes and shouldn't be used to suspend it.  Or something like
that... 

- Mike

-- 
Michael Spencer                  Nova Scotia, Canada       .~. 
                                                           /V\ 
mspencer at tallships.ca                                     /( )\
http://home.tallships.ca/mspencer/                        ^^-^^

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