What it shows:
A Van de Graaff generator will apply a charge to its dome and anything else in contact with the dome. Should that object be a person, they obtain a net surplus of charge (be it positive or negative). It is especially noticeable with hair, as each individual strand is repelled from every other and from the scalp.
How it works:
Details of the Van de Graaff are written in the Van de Graaff Generator demo. The volunteer should stand on an insulating platform (we use either a wooden stool, milk crate, or plastic bucket), and place both hands upon the Van de Graaff dome. The operator should switch it on and stand back. Before stepping down, allow the generator motor to stop, and discharge the dome with the earthed rod.
Setting it up:
Place the Van de Graaff in an open space on the hall floor. The bucket should be placed a reasonable distance from the base of the generator (the victim will need to lean across) so as to avoid discharge to other parts of the body. Remember to dry the wig overnight before the class with a heat lamp (don't put it too close or you'll melt it).
Obviously long hair is an essential qualification for the volunteer. Should there not be a suitable respondent, the lecturer (if they do not have the necessary locks) can be provided with a wig 1 Humidity (as with all electrostatics demos) plays a large role in the success of this display.
1 We have a long blonde model from Franklin Fashions Corp., Valley Stream NY 11580