The only observations we were told to take was the reading on the voltmeter. If it helps, we used different metals in the same solution, the higher reading we got was from Magnesium (considering we used Mg, Cu, Zn and Nickel)
In our prac, we also performed an experiment where we used the same metal but different concentrations of the NaCl (0.1 Mol, 1.00 Mol, 0.001 Mol), and we got higher readings the more concentrated the solution was. Would that help with anything?
If the experiment was like this, with an inert conductor http://community.boredofstudies.org/attachments/239/production-materials/29198d1384568000-galvanic-cell-chem2.4.11.png
And one of the electrodes was zinc and the other graphite, and the electrolyte was NaCl (Sodium Chloride), what is...