Date: Tue, 04 Sep 2001 23:57:55 +0200

Author: Simcha Segev

Subject: RE: Parametric resonance



As I described earlier, I already built and show this demo to the school
staff. Actually we operate it by the wooden stick on a pivot but we also try
do it with a variable low speed electric motor.
I find that it is easier to modulate to the right rhythm (frequency and
especially the phase) when using the wooden stick and not the motor.
It will be nice if you post me the photo from the Video Encyclopedia of
Physics Demonstrations as we don't have it yet.

Thanks, Simcha

Simcha Segev - Technical Manager
School of Physics and Astronomy
Tel Aviv University
Tel Aviv 69978
Phone +972 3 640 8077
Fax +972 3 642 9306

-----Original Message-----
[]On Behalf Of Jerry DiMarco
Sent: Tuesday, September 04, 2001 6:07 PM
Subject: RE: Parametric resonance

I have seen a variation of this demo in the Video Encyclopedia of
Physics Demonstrations (Disc 9, #4). Their explanation is the same as the
one you quoted below, but I'm not convinced. I think the method by which
one pumps up a swing is more involved. Do you have this demo, or are you
thinking about building it? The apparatus in the video is simpler. I can
post a photo if you'd like...