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    Corrosion happens when the atoms on the surface of an object undergo a chemical reaction with atoms from environment. The chemical reaction produces new substance that change the material's color or texture. These new substances might not bind to the material very tightly, so the material's surface might start to become rough or weak and is more easily worn away by wind or rain.

    Corrosion is a common problem with many metals. One of the metals that it affects most often is iron. When iron corrodes, it combines with water and oxygen molecules from the air to form a new substance called iron oxide, which is reddish-brown in brown. It is rust.

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