Cooking an egg is a great example of a chemical change because the heat from the pan or oven causes the proteins in the egg to denature, or unwind, and then re-form into a new structure. This is why a cooked egg is firmer and more solid than a raw one - the molecules have rearranged themselves into a more stable form. It's like a little miracle happening right before your eyes!
Now, you might be thinking, "But what about physical changes?" Well, those are changes that don't alter the substance's chemical makeup, like melting ice or dissolving sugar in water. These changes are reversible, meaning you can turn the ice back into water, or recrystallize the sugar. Not so with a cooked egg, my friends - once it's cooked, there's no going back!
