Final answer:
Cooking an egg involves a chemical change due to the irreversible alteration of egg proteins through denaturation, resulting in new substances. This differs from physical changes which are reversible and do not form new substances.
Step-by-step explanation:
The type of change involved in cooking an egg is a chemical change. This is because when you cook an egg, the proteins in the egg white and yolk change their structure in a process known as denaturation. This process is irreversible and results in new substances being formed, which is indicative of a chemical change.
Looking at other examples, such as the burning of gasoline or the souring of milk, we can also determine these as chemical changes because they involve the transformation of substances into entirely different products. In contrast, physical changes, like the melting of gold or dissolving of sugar in water, are reversible and do not result in the formation of new substances.