Re: power the world on urine! (was Re: photochemical advance)

Date: Tue Dec 11 2001 - 19:13:40 MST

Dossy writes:
> The question is, if I peed into my urine-powered clock before
> I went to bed every night, would it provide enough power so that
> it would keep good time when I woke up 8 hours later?

Actually the liquid just supplies a conductive electrolyte and is
not the source of the energy. A salt solution will work as well.

   How can you run a clock off of a potato?

   The classic technique is to insert two dissimilar metal strips into
   the potato in order to build a simple battery. You can then run an
   electronic clock with the power provided by that battery. But the
   energy in that battery is coming from chemical reactions of the metals
   and not really from the potato.


   The energy powering the potato clock does not come from the potato,
   but simply from the electrochemical properties of two different metals
   being placed into a salt solution. As the questioner correctly notes,
   cola also works, as does any simple salt solution--try it with table
   salt. The potato acts as a compact, slow-to-dry, salt bridge.

The metal electrodes are slowly dissolved (or at least one of them is)
as part of the electrochemical reaction. The power comes from the fact
that the different metals have different electrode potentials. It is
not coming from the electrolyte.


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