An array of diodes is layered between two aluminum plates. A temperature differential between the plates results in current being generated within the diodes. The electrical output is wired to a small motor/fan.

A cup of ice water and a cup of boiling water are supplied. Placed as shown in the picture, the resulting temperature difference causes current to be generated. If the unit is place in one or the other cup, the current flow stops; demonstrating that work done is dependent on the temperature difference.

This demo can be found in cabinet D on shelf 2 of the UCSD PUL Demo Room (WLH 2015).