Static electricity

Static electricity is charge that has built up and is sitting still, rather than flowing as current. Rubbing two materials together drags electrons from one to the other, leaving one surface positively charged (lost electrons) and the other negatively charged (gained electrons). The charge just sits there, waiting.

When enough charge piles up, the pressure to balance out gets so strong that it jumps the gap in a sudden spark — leaping through the air to neutralise. That’s the tiny zap you feel touching a doorknob after walking on carpet, or lightning playing out the very same physics on a colossal scale.

Small everyday static discharges often have limited energy, yet they can damage electronics or ignite a flammable atmosphere. Larger electrostatic discharges, including lightning, can be dangerous. High voltage and static charge should not be described as always harmless.