I did the following experiment:
Two electrodes (one made out of Iron,the other made out of Copper) are put into a (bluish) Copper(ii) sulfate lotion.
Then, one connect a voltmeter to them to measure the potential.
Finally, one disconnect the voltmeter and connect an Amperemeter to measure the electrical current.
-Copper accumulates around the iron electrode,forming a thick copper coloured slick around it.
-there is a potential of about 0.5 V between the electrodes, which stays for several minutes.
-when one connect the amperemeter, one can measure a current which stays at least for a few seconds. (didn't measure further)
-there is no (visible) activity around the copper electrode.
-the solution doesn't change its colour notably.
-especially, one could not observe any evolution of gas. (although this does not mean that there is absolutely no gas evolution)