Electric baubles

This a switch is called a piezo-electric. It is operated by pressing quartz crystal which is nothing more than common, transparent sand, and the resulting electric charge is quite considerable. Such a switch, together with two baubles that are hung on a twig will be used in our Christmas tree experiment. We will show the way two opposite charges attract each other.

The baubles are hung next to each other on a thin wire ( 0.1 cm in diameter) at a distance of 1 cm. At the other ends we connect them to the switch (you have to remove the metal cap first). When you press the switch on the baubles start to attract each other, or more precisely, to bang against each other quickly.

There is no doubt that for this experiment an electrostatic generator and foamed polystyrene balls wrapped in aluminium foil or covered in colloidal graphite might have been used. In that case ,however, it would no longer be a Christmas tree experiment.