Electrochemistry :  Galvanic (Voltaic) Cells
Luigi Galvani, 1791 - an Italian anatomy professor, discovered the flow of current between two metals through a frog's leg. 

Alessandro Volta - an Italian physics professor, constructed the first continuous source of electric current

Luigi Galvani
Alessandro Volta
Components of a Galvanic Cell
  • Half-cells  - One half of the galvanic cell (e.g. the oxidation half-cell or the reduction half-cell).
  • Anode - Electrode at which oxidation takes place.
  • Cathode - Electrode at which reduction takes place.
  • Salt Bridge - Connecting the two half-cells.
  • The cations, positive ions, flow toward the cathode to replace the cations that are being picked up at the electrode.
  • The anions, negative ions, flow toward the anode to balance the positive charge of the cations that are released from the electrode.
  • A device to detect the amount of current flowing through the cell (in volts).