* Chemical Change: Corrosion involves a chemical reaction between a material (usually a metal) and its environment. This reaction leads to the formation of new substances, often oxides, which are different from the original material.

* Alteration of Composition: The process of corrosion changes the chemical composition of the material. For example, iron rusting forms iron oxide (Fe2O3), which is chemically distinct from pure iron.

* Not a Change in Physical State: While corrosion can lead to changes in physical appearance (like rust forming on metal), it's not just a change in state (solid to liquid, etc.). It's a fundamental change in the chemical makeup of the material.

In contrast, a physical property is a characteristic that can be observed or measured without changing the chemical composition of the substance. Examples include color, density, melting point, and boiling point.