Van de Graaff with Fluorescent Bulb

A fluorescent light bulb can flicker and glow when brought near a Van de Graaff generator. The strong electric field from the charged dome excites the gas inside the bulb, demonstrating electrostatic discharge and how electric fields can cause visible light emission.

1. Turn on the Van de Graaff generator and allow charge to accumulate on the dome.
2. Hold a fluorescent bulb by its center and carefully bring one end near the dome.
3. Observe flickering or glowing inside the bulb as the electric field excites the gas.
4. When finished, discharge the Van de Graaff using the grounding rod before turning it off.

Van de Graaff generator versus fluorescent lights & spectral tubes - AHC Electricity & Magnetism:

📄 Van de Graaff with Fluorescent Bulb - Iowa State University: https://learning.physics.iastate.edu/van-de-graaff-fluorescent-bulb

• Try bulbs of different sizes (compact vs. long tube) to compare brightness.
• Place the bulb in contact with the dome versus holding it a few centimeters away to compare effects.
• Demonstrate in a darkened room for better visibility.

• Always discharge the Van de Graaff with the grounding rod before touching or turning off.
• Hold the fluorescent bulb by the insulated middle section—avoid touching metal ends near the dome.
• Do not use around sensitive electronics or students with pacemakers.
• Warn students about possible startling flickers or sparks.

• Why does the bulb flicker even without being plugged in?
• How does the Van de Graaff’s electric field excite the gas in the bulb?
• Why is the effect stronger near the dome than farther away?
• What similarities exist between this demonstration and how lightning excites gases in the atmosphere?
• How does this relate to how fluorescent lamps work in everyday life?