Cooking an egg is primarily a chemical process. When you heat an egg, the proteins in the egg white and yolk undergo a chemical change called denaturation. This process alters the structure of the proteins, causing them to unfold and then bond together in new ways. As a result, the egg changes from a liquid to a solid state. This transformation is irreversible, which is a key characteristic of a chemical change.
Additionally, the heat causes other chemical reactions, such as the Maillard reaction, which gives the cooked egg its characteristic flavor and color. These changes are not just physical alterations in appearance or state but involve the breaking and forming of chemical bonds, making cooking an egg a chemical process.