The electric plume has a number of colored ribbons attached to a vacuum cup.
When mounted on the dome of a Van de Graaff generator, the ribbons will slowly acquire a charge, even though they are normally thought of as insulators or non-conductors.
As the charge builds, the ribbons will stand away from the dome and from each other. This is a vivid demonstration showing that like charges repel one another.
Suction cup diameter: 6 cm
Plume colors will vary