Handheld Lightning Rod

Van de Graaff generators produce voltages exceeding 100 kV. While current is limited and typically not lethal, shocks can be painful and may cause involuntary muscle contractions leading to falls or equipment damage. Never allow students to approach the generator while operating. Maintain at least 1 meter clearance from individuals with pacemakers or other implanted electronic devices.

Strong electric fields and electrical discharges can damage sensitive electronics including computers, phones, calculators, and hearing aids. Ensure all such devices are kept at least 1 meter from the generator during operation. Consider requiring students in the front rows to turn off or remove such devices.

Purpose

Demonstrates electric field concentration at sharp points and the lightning rod principle. A grounded paperclip on a wooden dowel silently bleeds charge from a Van de Graaff dome, stopping visible sparks to a nearby grounded sphere.

Van de Graaff generator with large dome and smaller grounded discharge sphere on stands, wooden dowel with paperclip visible at upper left, power strip in foreground

Closer view of Van de Graaff dome and grounded sphere with a spark visible between them, red grounding wire connected at base

Figure 1: Van de Graaff generator with grounded discharge sphere and handheld paperclip lightning rod (wooden dowel, upper left).

Figure 2: Spark discharge between the Van de Graaff dome and grounded sphere — the sparks stop when the paperclip is brought near the dome.

Danger: High Voltage Electrical Hazard

Warning: Electronic Device Protection

Purpose

Safety Warnings

Danger: High Voltage Electrical Hazard

Warning: Electronic Device Protection

Purpose