Testing simple cell electrodes

Testing simple cell electrodes

ZIMSEC O Level Combined Science Notes: Experiment: To measure the potential difference of a simple cell

Aim: To measure the potential difference of a simple cell when different electrodes are used

Materials: dilute sulphuric acid, voltmeter, beaker, leads and crocodile clips, magnesium ribbon,lead foil, copper foil, iron, sandpaper


  1. Place 75 cm of dilute sulphuric acid in a beaker
  2. Clean each electrode with sandpaper
  3. Coil the magnesium ribbon around a pencil
  4. Dip a pair of electrodes into the sulphuric acid to about half their length
  5. Lightly touch the electrodes with a pair of leads connected to a voltmeter
  6. Always touch the least reactive metal electrode with the positive lead terminal of the voltmeter

Results and Observation

  • A current flows when two different metals are used as electrodes
  • The least reactive metal is the positive terminal
  • The most voltage is obtained when the least reactive metal (copper) and
  • The most reactive metal (magnesium) are used
  • If the same metal is used no current flows and no voltage is recorded

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