5287 Human battery

Placing your hand on two of the four metal plates (zinc, lead, aluminium and copper), you create a potential difference between the plates because of the electrical conduction properties of the human body. This potential difference can be measured through the use of a millimetric voltmeter (not included). Trying all possible combinations between metals, it is possible to guess the existence of the electrochemical series.
Plates dimensions: 15×23 cm.
Board dimensions: 23×65 cm.