Iron is often galvanized in order to protect it against corrosion. Galvanizing involves coating the surface of iron with a layer of zinc. Zinc is more reactive than iron, which means that when the iron is exposed to oxygen and water, the zinc sacrificially corrodes instead of the iron. This protects the iron from rust and other forms of corrosion, which can weaken and damage the metal. The zinc layer also acts as a barrier between the iron and the environment, helping to prevent moisture and other corrosive substances from reaching the iron surface. As a result, galvanized iron is often used in outdoor applications where it is exposed to moisture and other corrosive elements, such as fences, roofs, and gutters.