A simple demonstration, which can be developed into a class experiment/investigation.
Electrodes of two different metals are dipped into an electrolyte – coca cola in this case. the resulting current can be used to power an electric clock.
The activity can be altered/extended to include using fruit or vegetables as the electrolyte or trying different metal electrodes.
Image from Cool Clips – http://clipart.coolclips.com/480/vectors/tf05189/CoolClips_vc017298.png
