Spark

If oppositely charged objects are brought sufficiently close, electrons may suddenly cross the air gap from the negatively charged object towards the positively charged object. This rapid electrical discharge reduces the charge imbalance and can produce a visible spark, heat and sound.

Electrons can suddenly move through the small air gap and into the conductor. This rapid transfer is a brief current, producing a spark and the sensation of an electric shock.

Charge then moves suddenly through the air: this brief discharge is a spark. It may be visible and make a crackling sound, as when a charged Van de Graaff dome sparks to a nearby conductor. The spark is not charge being made; it is charge that had built up being released.

Charge then moves rapidly through the air, producing a spark. The spark is an electrical discharge that reduces the charge imbalance. A small shock after walking across a synthetic carpet and then touching a metal object is a familiar example.