Daniell Cell

This experiment demonstrates a copper-zinc cell (Daniell cell), as an example of a of electrochemical cell. A zinc sheet and a copper sheet are put into their appropriate ion solution: Zinc into zinc sulphate and copper into copper sulphate. Zinc is less noble than copper and the solution tension is higher. Thus, a relatively large number of zinc ions enter the solution at the zinc sheet, i.e., zinc atoms are oxidized to zinc ions. The electrons remain in the zinc sheet (surplus of electrons), which is charged negatively. On the other hand, only a few copper ions detach themselves from the copper sheet. Electrons flow to the copper sheet via the cable that connects the metal sheets to a voltmeter. The copper ions of the copper sulphate absorb these electrons and attach to the sheet as solid copper, i.e., the copper is reduced. Since positive zinc ions are in the solution on the left and copper is deposited on the right, a charge equalization must take place. To allow such an electric current, both half-cells are connected with a salt bridge – realized by a paper towel dipped in sylvite. Sulphate ions move to the left and zinc ions to the right.

This is an experiment from the first-semester lecture "Electricity and Magnetism" given by Christian Bettstetter in the bachelor program "Informationstechnik" at the University of Klagenfurt, Austria.
Link to the lecture: https://bettstetter.com/teaching/epgi/
Video made by Judith Wieser.
Text by Christian Bettstetter and Judith Wieser.
Supported by Stefan Amlacher in the laboratory of HTL Mössingerstraße, Klagenfurt.
(c) 2021 Universität Klagenfurt