Van de Graaff Hair Raising

Materials: ★★☆ Available in most school laboratories or specialist stores
Difficulty: ★★☆ Can be done by science teachers
Safety: ★★★ Only to be attempted with adequate safety procedures and trained staff

Categories: Van de Graaff Generator

Alternative titles: Electrostatic Hair Demonstration

Summary

When a person touches the dome of a Van de Graaff generator while standing on an insulator, the charge spreads over their body and onto their hair. Each hair strand, carrying the same type of charge, repels the others, causing the hair to stand on end.

Procedure

Place the Van de Graaff generator in an open area of the room.
Set an insulating platform (e.g., wooden stool, milk crate, or plastic bucket) near the generator.
Have a volunteer with long hair (or wearing a wig) stand on the platform.
Ask the volunteer to place both hands on the dome.
Switch on the generator and step back.
Observe the hair gradually rising and separating as electrostatic repulsion increases.
Before the volunteer steps down, turn off the generator and discharge the dome with a grounding rod.

Links

Long hair vs. Van de Graaff generator - Tibees:

Hair Raising Van de Graaff Generator - FlinnScientific:

📄🎞️ A hair-raising experience with a Van de Graaff generator - TKSST: https://thekidshouldseethis.com/post/hair-raising-van-de-graaff-generator-video

Variations

Use a wig if no long-haired volunteer is available.
Record the process on video and play back in slow motion to better observe the gradual lift.
Dim the lights and show sparks jumping from the person’s body to a grounded object for added effect.

Safety Precautions

Always discharge the dome with a grounding rod before the volunteer steps down.
Ensure the volunteer stands on an insulating platform to prevent unintended shocks.
Avoid this demonstration with individuals who have pacemakers or other electronic medical devices.
Perform in dry conditions for best results - high humidity reduces effectiveness.
Keep the generator away from sensitive electronics.

Questions to Consider

Why do the hairs repel each other instead of staying flat?
What role does the insulating platform play in the demonstration?
Why is long hair more effective for this demonstration than short hair?
How does humidity affect electrostatic demonstrations?
What real-world phenomena does this model (e.g., lightning, static cling)?