Electrolysis is an important process in industry and chemistry. It is used to separate the chemical components of a substance. Aluminium, for example, is obtained by electrolysing its molten ore.
The electrolysis of water results in the production of hydrogen and oxygen. Hydrogen serves as a source for "clean energy". When hydrogen is burnt, it will produce only water but no other harmful gases.

The "hydrogen rocket" experiment demonstrates the circle of the production and the burning of hydrogen in a fascinating and illustrative way. Moreover, it is a good example for the transformation of energy: kinetic energy (energy of movement) is transformed into chemical energy (which is stored in the two gases hydrogen and oxygen). This energy is released again as heat when the two gases recombine (in an explosion) and forces the "rocket" to move along the wire (again kinetic energy).

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   Description of the Experiment   

By turning a handle of a generator, you are able to provide the electric energy needed to electrolyse some diluted acid. Eventually, the generated gas mixture of hydrogen and oxygen forces the liquid below the electrode and prevent further generation.

Pressing a fire button releases the gases (via electrical operated valves) into a combustion chamber and initiates the firing sequence. Ignition is caused by a spark plug and the rocket is projected far up along a wire which is attached to the ceiling. Once returned to its original position the rocket is ready for a new visitor to conduct the experiment.

   Duration   

The whole experiment lasts about 2 minutes, depending of the "muscle power" of the visitor(s) turning a handle.

   Conclusion   

Two or more connected atoms form molecules. Chemistry is the science of the synthesis of molecules through the break of bonds and the combination with other atoms or molecules. Chemistry is about the transformation of substances.

Water is made of two atoms of hydrogen and one atom of oxygen. Its chemical formula is H2O. Electrolysis of water (-lysis means "splitting" or "breaking down") leads to hydrogen (H2) and oxygen (O2) gas.

   Detailed Conclusion   

The basic reaction that takes place in the experiment is expressed by the equation:

2H2O    2H2+ O2

This reaction illustrates the law of definite proportions. The law of definite proportions is the basis for chemical formulas. It not only expresses that a compound has a constant composition but also expresses that it has constant properties e.g. pure water always dissolves salt.

The electricity to generate hydrogen from water can be provided by several methods. Using solar energy would require storage of energy for use at night and cloudy days. The hydrogen could be transported in tanks or through pipelines to be used as fuel when and where it is needed.
Modern technology uses hydrogen in "fuel elements" producing the electric energy to run a car.