Re: dielectric constant of water

[Wolfgang Rueckner <rueckner@FAS.HARVARD.EDU>]

> Setting an experimental measurement around 35pF is on the low side,
> where extraneous effects can blur capacitance results.
> If desiring to measure k for water, I'd suggest it is better to measure
> the effect of a water dielectric. (No extraneous dielectrics...)
>
> I think you will be pleased with results.
>
> As to the high-side anomaly - though I'm not sure this is the cause,
> let me ask: what would you expect to read in your setup with a strong
>   salt solution in the bag? or a thick metal plate in the bag?
>
> Brian Whatcott   Altus OK


With a thick metal plate in the bag, I would expect the capacitance
to increase.  I see that you're suggesting that salty water would act
like a thick metal plate producing, in effect, two capacitors in
series whose dielectric is the thin plastic bag. Being thin, the two
caps have a very small plate separation which produces a large
capacitance, but having the two in series cuts that large capacitance
in two.  Is that right? -- Wolfgang
--
Wolfgang Rueckner
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