Description: This demonstration illustrates the buildup of charge on someone’s hair.
Equipment:
- Van de Graff
- Discharge wand
- Insulated wand
- Milk crate (or another sturdy insulator for someone to stand on)
- Lite Metal rod
Setup Procedure:
- Connect the Van de Graff machine to an outlet with a thrid prong (grouded prong); else you may get zapped when turning it off.
- With the machine off, set it to 3/4 speed.
- Connect the discharge wand to the black grounded jack on the machine.
- Place the insulated milk crate and insulated wand near the Van de Graff.
Demonstration Procedure:
- Have an assistant with long dry hair remove all metal objects and electronics from their body.
- Have them stand on the insulated stand.
- Have them hold one hand on the machine, and have them hold the metal rod in the other hand.
- Make sure they are away from anything that their body could discharge to (such as the machines power cable).
- Instruct the assistant to not take their hand off the machine until you tell them to.
- With the machine at 3/4 speed, turn it on and move back.
- Wait a few minutes, with your assistant shaking their head periodically.
- After a few minutes their hair should be standing up on end if it is dry in the room.
- When you are ready to turn off the machine, instruct the assistant to not move the wand toward you.
- Using the insulated wand, turn off the machine (with the insulated wand touching the switch).
- Have your assistant take their hand off the machine.
- Warn your assistant they will get a small shock and touch the discharge wand to the metal rod they were holding.
- The assistant can now step off the create and you may discharge the dome with discharge wand.
High Voltage
Due to the high voltage, keep away from sensitive electronics.
Never have a student touch the Van de Graff who has any electronics in their body such as a pacemaker.
Make sure your assistant is not standing near anything they could discharge to.
Physical pain can result if you discharge them while their hand is still on the Van de Graff.
Note: As with most electrostatic demonstrations, they work best under 50% humidity.