A plate of zinc and a plate of copper immersed in a dilute solution which contains acid or salt is an example of the chemical reaction based cell. The solution acts as an electrolyte (electric conductor). When the two plates are connected to a current meter with a wire, electric current will pass; this is because oxidation and reduction processes take place in this chemical reaction turning the zinc plate to a negative electrode and the copper plate to a positive electrode, and so the electrons flow from zinc to copper.