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Re: Too quiet? You just need a smoke-ring gun!



I probably mentioned this on PHYS-L long ago, but here's a possible
smoke-ring experiment below

Seal a fairly big loudspeaker (over 6") in a hole in the side or bottom of
a small wastebasket, then put a flat plate over the top of the wastebasket
and cut a hole in the plate (maybe a 10cm hole to start.) Touch the
speaker leads briefly with a battery to "fire" the smoke ring. Next, make
it programmable...

Add an audio amp, and drive the system with a pulse from a signal
generator or even better, from a soundcard (perhaps a programmable drum
program would let you sculpt the waveform? Or just use visual basic?)

I suspect that the shape of the pulse waveform can be used to "program"
the smoke ring, since the air which flows over the edge of the orfice ends
up "wrapped around" the core of the ring.

E.g. if the pulse rises and then slows down, the smoke ring would
have a fast-spinning central core, but the ring itself would drift
forwards slowly. Or if the pulse starts out slowly and then speeds up,
the smoke ring would have a slow core, but the whole ring would fly
forwards very quickly.

Even if this doesn't work, you could still use a programmable pulser to
generate interesting patterns of rings. For example, a series of rings
with increasing velocity should "catch up" until each ring tries to
penetrate the center of the one ahead of it, and momentarily the chain of
rings compresses together and forms a flat "bulls-eye" pattern.

See http://amasci.com/amateur/vortgen.html

(((((((((((((((((( ( ( ( ( (O) ) ) ) ) )))))))))))))))))))
William J. Beaty SCIENCE HOBBYIST website
billb@eskimo.com http://amasci.com
EE/programmer/sci-exhibits science projects, tesla, weird science
Seattle, WA 206-789-0775 sciclub-list freenrg-L vortex-L webhead-L