Separating Water into Gas

This experiment uses electricity to split water molecules into hydrogen and oxygen components. Fill up a tray or basin with tap water to make a water bath then set up a pneumatic trough by placing electrode terminals into two upside-down beakers (each filled with water) in the water bath. 

The opposing charges of the atoms in the water molecule are attracted to the positive and negative electrode terminals. As this happens, the top of the inverted glass fills with gas and starts to displace the water downwards. Hydrogen forms at the negative pole, and oxygen forms at the positive pole. 

The best electrodes to use are made of platinum, but this experiment can be done with copper, for example. You can connect five-volt square batteries in series to increase the current, which in turn speeds up the reaction. 

Water by itself isn t a good conductor of electricity because it has only a small amount of electrolytes present. (Electrolytes are charged ions that can help transmit current see Chapter 8 for details.) The more electrolytes in a solution, the more conductivity the solution displays. 

Hook up a battery to a light bulb by connecting the negative terminal to the bulb, connect the positive terminal to the water, and have another piece of wire going to the other terminal of the light bulb. This should be a closed circuit whereby the concentration of electrolytes in the solution alters the current allowed to pass through the solution. The amount of current can be 

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