Re: [Phys-l] Dancing Droplets: Water Droplets Orbiting in Micro-Gravity [Video]

[Bernard Cleyet <bernardcleyet@redshift.com>]

On 2012, Feb 08, , at 09:54, John Denker wrote:

> On 02/08/2012 09:05 AM, Donald Polvani wrote:
> > Thanks!  Just what I needed for a demo in our qualitative electrostatics lab
> > this afternoon!
>
> > On Behalf Of Robert Sciamanda
>
> > Check it out===>
> > http://www.howtogeek.com/104982/dancing-droplets-water-droplets-orbiting-in-
> > micro-gravity-video/  		
>
>
> Ask the kids:
> -- Why was there a second knitting needle near the nozzle where 
>  the droplets were produced?
>
> -- Was the second needle (a) uncharged, (b) charged the same
>  as the main needle where the droplets orbit, or (c) charged
>  oppositely?  How do you know?
>
>
> Huge hint (also interesting in its own right):
>  uggc://ra.jvxvcrqvn.bet/jvxv/Xryiva_jngre_qebccre
>
> That's what I call high-quality qualitative electrostatics.


For the sl. more advanced.   Why do the elliptically orbiting drops precess while the planets (ideally or approximately) do not?


Here's an applet for various force laws.

http://www.kw.igs.net/~jackord/bp/f7.html

bc doesn't have the required application for JD's hugh hint.