Water Electrolysis Experiment


This experiment allows for a study of the electrolysis of water without the use of the traditional Hoffman apparatus. An experimental study of the electrolysis of water can be used to demonstrate oxidation-reduction reactions or to illustrate the use of an external source of energy to drive a non-spontaneous chemical reaction. 

The relative volumes of the gases produced and the reactions of the gases to the glowing and burning splints can be compared with the theory of the production of oxygen at the anode and hydrogen at the cathode. The colors produced at each electrode can be used to identify the production of hydrogen ion at the anode and hydroxide ion at the cathode.

Educational Value Statement

  • Describes electrolysis, in particular water electrolysis.
  • Describes an experiment of the electrolysis of water without the use of the traditional Hoffman apparatus.
  • Can be used as a demonstration experiment.
  • Describes further experimenting options for be investigated.
  • Explains the half reactions that occur at the anodes and cathodes for each type of electrolyser.
  • Can be downloaded as a PDF File.

Key Learning Objectives

  • students explain chemical processes in terms of atoms and energy transfers 
  • students identify the ratio of hydrogen and oxygen gas production.
  • Students explain how chemical reactions are used to predict the relative quantities of chemicals produced.
  • Students explain how different factors influence the rate of reactions. 
  • Students explain the concept of energy conservation and represent energy transfer and transformation within systems. 



  • Science Understanding: Chemical sciences
  • Science Inquiry Skills