Physics Dept. Demonstration Manual

DEM04 - Hair-Raising Demonstration, "Human Electroscope"


To illustrate distribution of charges and lines of force of the field.

  • Student
  • Van-de-Graaf generator
  • Aluminum sphere
  • Insulating stool


A student (or instructor) with fine dry hair, stands on an insulating stool and places both hands on the sphere of the generator. (Make sure that the generator was previously discharged to prevent shock). When the generator is energized, the hair tends to rise and extend along the lines of force of the field about the head. After the experiment, the student must hold on to the sphere until it is discharged. Or, the aluminum sphere is moved into contact with the generator by another person, to discharge the spheres.