Final answer:
Boiling an egg is a physical change, as no new substances are formed. The denaturation of proteins in the egg white leads to coagulation and solidification.
Step-by-step explanation:
Boiling an egg is a physical change. It falls under the category of physical changes because no new substances are formed during the process. The change from liquid to solid occurs due to the denaturation of proteins in the egg white, which leads to the coagulation of proteins and the solidification of the egg white.