You probably use the terms “tin foil” and “aluminum foil” interchangeably, but hold onto your (foil) hat, because it may surprise you to learn that aluminum foil and tin foil are two different things. Here’s how the names became synonymous, and the real differences between these two kitchen equipment staples.

Tin foil and aluminum foil do pretty much the same thing, but their histories are different. Before the 1900s, tin foil was used for industrial purposes, and because it was heat resistant, heat conductive, and easily moldable, it became so popular it was eventually sold commercially to be used in homes.

In the early 1900s, aluminum foil rose in popularity; compared to tin foil, it was significantly cheaper to manufacture and didn't leave a metallic-tasting residue on foods. Tin foil eventually became obsolete, but its name has become so synonymous with metal foil that we still say "tin foil" when referring to aluminum foil.