1.   An electric arc, or continuous spark, flows between a metal electrode and the steel.

2.   In electrolysis you attach a battery to two metal electrodes which are dipped into a sodium chloride solution.

3.   They do this by coating a metal electrode with the polymer and then varying the voltage applied to the metal.

4.   A typical fluorescent lamp is a tube with metal electrodes at each end.

5.   EEGs use metal electrodes encased in plastic that are placed on the scalp.

6.   The cavities are cylindrical in shape, with metal electrodes embedded on the floor and one side.

7.   These were colorful flashes of energy created inside sealed glass tubes, virtually emptied of air, when electricity was applied to metal electrodes in the tubes.