In article ,
harry k wrote:
On Jul 16, 9:34*am, Smitty Two wrote:
In article
,
*harry k wrote:





On Jul 15, 9:42*pm, Smitty Two wrote:
In article
,
*harry k wrote:

....

I wonder if there is a cheap strobe light out there. They were fun to
play with back in HS physics.

Shine a bright light-BEAM, in a DARK ROOM, through a fan, and have someone
swing a yo-yo or something in a circle -- and vary the yoyo-speed,
and the fan-speed.

MAYBE the effect will show up.


AH! Or have the through-the-fan light-beam shine on ANOTHER fan!

Try them BOTH.


(Dog chasing tail?)


David