To electroplate means to coat a metal object with a thin layer of a different metal using electricity. Picture a plain steel spoon being dipped into a special liquid bath: when electricity flows through the liquid, tiny particles of silver or gold stick to the spoon's surface, one microscopic layer at a time, until it gleams with a bright metallic coating.

Electroplating works by passing an electric current through a liquid containing dissolved metal particles. The object to be plated attracts these particles, pulling them from the liquid onto its surface. After enough time, the coating becomes thick enough to protect the base metal from rust or simply make it look more attractive.

Jewelry makers electroplate inexpensive metals with gold or silver to create beautiful pieces at lower costs. Car manufacturers electroplate chrome onto bumpers and trim for that mirror-like shine. Even pennies minted after 1982 are electroplated: they have zinc cores coated with copper, which is why older solid copper pennies feel slightly heavier.

The process was invented in the 1800s and revolutionized manufacturing. Before electroplating, coating objects with precious metals required dangerous chemicals or intense heat. Electroplating made it safer, cheaper, and more precise. Scientists also use electroplating to protect spacecraft parts from corrosion and to repair worn machinery by building up metal on damaged surfaces.