Artsy Citrus Clock turns lemons into time of day

[Noels]

"Citrus" clock

This clock runs on the energy of a lemon, which powers it for a week or longer.

This pedagogic project is a kind of shortcut intended to remind ourselves that nature, in spite of the various transformations to which we subject her, is still our direct energy source.

The somewhat magical dimension of the operation is in fact simple electrolysis, like a conventional electric battery

More details:

Technically, it's almost the same principle than Mr Volta used to invented the battery in 1799: an electrolysis of zinc and coper (the plug under the lemon) in an salted or acid liquid (the lemon). The oxidation phenomenon create the electricity.

If you were lucky enough, this chemical experience use to be teach in primary school (in france at least).

We call that a pedagogic project because the aim is obviously not to replace our actual clocks, but at least to help people think (or remember) about nature and energy.

[Stefan09]

Cool idea, but wont you have an issue with fruit flies before your "battery" is dead?

[Quimby]

IT is *NOT* the lemons that power this thing. The lemons simply provide an electrolytic solution (citrus acid in water) that connects the two metal electrodes. When connected, the electrodes undergo a redox reaction --- akin to water on iron causing oxidation into rust. The actual energy powering the clock came originally from all the energy used at the metal factory to reduce the metal oxide ore into pure copper or tin.