What is static electricity?
Static electricity is electric charge that builds up on you when materials rub together, like your sweater, shoes and carpet. It has nowhere to go until you touch metal, and then it jumps across in a tiny spark: the zap you feel.
Rubbing moves tiny charges around
When two materials rub together, like a wool sweater against your skin or rubber soles on a carpet, electrons get pulled from one to the other. One side ends up with extra charge, the other with too little.
Share this stepThe charge builds up on you
The charge spreads over your body and has nowhere to go, especially if you wear rubber-soled shoes. Walking across a carpet can charge you to several thousand volts without you noticing.
Share this stepThe charge jumps to the metal
When your finger gets close to metal, the charge suddenly finds a path. It leaps through the air in a tiny spark, a mini lightning bolt. That’s the snap you hear and the sting you feel.
Share this stepA tiny lightning bolt from your fingertip.
Rubbingbuild-upzap
The voltage is high but the amount of charge is tiny, so the shock is harmless. It’s worse in winter, because dry indoor air lets the charge build up instead of slowly leaking away.
Common follow-up questions
Why do I get more shocks in winter?
Heated indoor air is very dry. In humid air, a thin film of moisture lets charge leak away gradually. In dry air it builds up until it sparks.
How do I avoid shocks from door handles?
Touch the metal with a key or coin first, so the spark jumps from that instead of your finger. Cotton clothes, leather soles and a humidifier help too.
Why do I get a shock getting out of the car?
Sliding across the seat charges you up. Hold the metal door frame as you climb out, and the charge leaks away without a spark.
Is static electricity dangerous?
For people, no. But a spark can ignite fuel vapors, which is why you shouldn’t get back into the car while refueling, and it can damage electronics.
