Pro 🔒~10 min
John Travoltage
Build up static charge and trigger a spark discharge
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How it works
John Travoltage demonstrates a key principle: When a shoe rubs against carpet, electrons transfer from carpet to shoe (or vice versa) due to the triboelectric effect. When a shoe rubs against carpet, electrons transfer from carpet to shoe (or vice versa) due to the triboelectric effect. The accumulated charge creates a voltage across the body. When this voltage is high enough (air breakdown at ~3 MV/m), a spark discharges the built-up charge through the ionized air path. Humidity allows gradual charge leakage, reducing maximum charge buildup.
Step-by-step
- Click and drag the shoe back and forth across the carpet to accumulate charge.
- Watch the charge indicator rise.
- Move the hand toward the doorknob — when it gets close enough, a spark discharges the charge.
- More rubbing = larger spark.
Key formulas
- Voltage from accumulated charge
- Air breakdown field
Frequently asked questions
- Why does the spark jump to the doorknob before you touch it?
- High electric field ionizes air at close distances, creating a conductive path.
- Why is static discharge worse in winter than summer?
- Low humidity in winter means less conductive moisture on skin/carpet for gradual discharge.
- Why are electronics stored in anti-static bags?
- ESD can damage transistors with voltages as low as 10V — far less than a painful spark.