Pedagogical Voltaic pile

The voltaic pile was the first electrical battery that could continuously provide an electric current to a circuit. It was invented by Italian physicist Alessandro Volta, who published his experiments in 1799.

This pedagogical pile is made to be used with coins of 5 euro cents.

You can find great explanation in this YouTube vidéo...
https://www.youtube.com/watch?v=edMN7P5oCaY