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.

Pro 🔒~10 min

John Travoltage

Build up static charge and trigger a spark discharge

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.

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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

$V = \frac{Q}{C}$ Voltage from accumulated charge
$E_{spark} \approx 3 \text{ MV/m}$ 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.