Re: Coulomb’s force lab.

[Brian Whatcott <inet@INTELLISYS.NET>]

At 04:34 3/28/02 -0500, Ludwik wrote:
> We have purchased a Pasco torsion balance to measure
> Coulomb repulsive forces, F. ...

>  my experience with (a) and (b)
> is not great. Results are not reproducible; differences as
> large as 10% are common. What is the remedy? The air
> is dry and I always allow the same time (2 minutes)
> between the moment of charging the spheres and the
> moment of reading of F.
>
> The charging is performed by touching each sphere
> (a ping pong ball coated by carbon) with a wire
> connected to a 6000 power supply. ...

> Any advice?
> Ludwik Kowalski

It will do no harm, and may in fact render the char.ge transfer more
repeatable, to furnish the charging
wire with a conductive ball too.

Brian W