Now that the proteins are all unravelled and flailing around, they start to cling to each other. They form new bonds, linking together into a mesh-like network. This is the chemical change that actually cooks the egg.
This process is called coagulation, which is just a scientist’s way of saying “the egg gets solid and turns white.” Water gets trapped in that protein mesh, which is why a cooked egg is firm but still a little jiggly. If you kept heating it, you’d squeeze all that water out, and you’d get a rubbery, sad disc.
Cooking An Egg Chemical Change
Why It’s Not Just a Physical Change
You might wonder, “Can I un-cook an egg?” The answer is a firm, glorious no. When you scramble an egg, you’re doing chemistry that you cannot undo. Unlike melting butter (a physical change), cooking an egg creates new arrangements of molecules.
The proteins have permanently shaken hands. They’ve formed new chemical bonds that won’t break if you try to cool them down. It’s like trying to un-bake a cookie—you might have cookie crumbs, but you’ll never get that dough back. That’s the signature of a chemical change.
