Like a sour version of the Eco-Friendly Water-Powered Clock, this timepiece runs on the energy of a lemon, which makes it possible to power 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.

Head over to the annagram.fr website for more photos of the Citrus Clock.

(Core77 via Geeky Gadgets and OhGizmo)