Re: Free Electricity !

On 20 Oct, 09:19, fbur...@xxxxxxx (Francis Burton) wrote:
In article <51f6d0d3-a39d-4f30-b1aa-692335085...@xxxxxxxxxxxxxxxxxxxxxxxxxxxxx>,





Ste  <ste_ro...@xxxxxxxxxxx> wrote:
In that case, I don't think the vacuum capacitor can work
in the same way. The two conductors of the Leyden jar can
be touched together before re-assembly and you will still
get a spark, which surely means it is the dielectric that
is storing the charge (or maintaining charge separation).

This is not how I understand the Leyden jar. Wikipedia (for what it is
worth) says clearly: "developments in electrostatics revealed that the
dielectric material was not essential". In fact, the same article
states that a dielectric, other than a vacuum itself, is not required.
Separating two conductive plates, with only a vacuum between them,
will suffice.

In fact, as I am reading down the article, I've come to this: "The
"dissectible Leyden jar" myth". I suggest this may be the source of
the misunderstanding. Apparently, this myth was taught in schools
"throughout the 1800s".

Hmm, this is interesting, if only as an example of how false
memories can be constructed, because I (seem to) distinctly
remember this being demoed. I don't think it was at school,
so that leaves TV - maybe one of the Royal Instution Christmas
lectures? Or not, if the whole thing is a mental fabrication!

The fuller article suggests that this effect can be created
(artificially, as it were) by two means: firstly the dielectric itself
can be polarised and retain some charge in a process known as
"dielectric absorption" (allowing the plates to be disassembled and
shorted, and yet the capacitor will develop a potential again when
reassembled), and secondly the surface of the dielectric can be
contaminated with moisture (which will retain some charge when
disassembled).
.

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