The freezing of water to form ice is a physical change, not a chemical change. A physical change is a change in the form or appearance of a substance, but not in its chemical composition. In the case of water freezing, the water molecules are simply rearranging themselves into a more ordered crystalline structure, but the chemical bonds between the hydrogen and oxygen atoms remain the same.

A chemical change, on the other hand, involves the breaking and forming of chemical bonds, resulting in the formation of new substances with different chemical compositions. For example, when iron rusts, the iron reacts with oxygen to form iron oxide, which has a different chemical composition and properties than iron.