PURPOSE: To show electric charge repulsion.
DESCRIPTION: Stand on an insulating stool and place one hand or both hands on the Van de Graaff dome. Have someone turn on the dome while keeping the grounding sphere far away. The fact that your hair stands on end is a result of the repulsion between the charges of the same sign that collect on your hair.
Be careful to keep your hand on the dome without removing it or you may get shocked. Also, check that you do not have metal jewelry with sharp points, such as ear rings, rings, bracelets or belt buckles. These metallic points will bleed the charge away.
EQUIPMENT: Van de Graaff generator, stool, volunteer.
SETUP TIME: None.
DEMO NOTES: Discharge the dome when done using a lightning rod needle. The victim will be harmlessly and painlessly discharged through the soles of their shoes when they step off the stool WHILE KEEPING THEIR HAND ON THE DOME at all times.
REFERENCES: Scott C. Dudley, Bret D. Heerema, and Ryan K. Haaland, The human discharge chain, APJ 65, 553-555 (1997).
"Van de Graaff Generator" at Hyperphysics <http://hyperphysics.phy-astr.gsu.edu/hbase/electric/vandeg.html> Includes video of demonstration
Updated by Jun Qi in 3/9/2000