Static electricity is the study of electric charges at rest, not flowing as an electric current. Ordinary uncharged atoms have equal numbers of positive protons and negative electrons. On the everyday (macroscopic) scale, electrically charged objects are ones that have either too many or too few electrons. Coulomb's law relates the forces that charged bodies have on each other to their charge and the distance between them.

Static electricity can be produced by friction, such as by combing hair (which acquires a negative charge) or rubbing nylon material. Electrons may then jump off as a spark, shocking anyone touching the object. Lightning is the result of a large-scale build-up of static electricity. This form of electricity is studied in the branch of physics known as electrostatics.