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Physics

Why Do Electrical Sparks Appear When Unplugging Appliances?

Quick fact

The spark you see when unplugging an appliance is a miniature electrical arc: the air in the gap becomes briefly conductive because the voltage causes it to ionize, and a current continues to flow until the gap is too wide to support it.

Why this is interesting

You yank the charger out of the wall and see a tiny blue flash. Why does electricity arc out of a socket that should be closed when nothing is connected?