Leyden jar

A Leyden jar is an early device used to store static electric charge. It consists of a glass container coated inside and outside with metal foil, with a metal rod connecting the inner foil to a terminal. When you connect it to a source of static electricity, charge accumulates on the metal surfaces, creating a separation of electrical energy that can be discharged in a sudden spark. Essentially, it acts like a primitive capacitor, storing electrical energy for experiments and demonstrations about electricity and lightning.