How id there a physical change in muffins?

A physical change in muffins occurs when they undergo various processes during baking, such as mixing ingredients, rising, and cooling. These changes alter the texture and appearance without changing the chemical composition of the ingredients. For example, when batter is heated, it transforms from a liquid to a solid state, resulting in a fluffy, baked muffin. This transformation is reversible in some aspects, as the muffin can be broken down back into its original components, though it cannot return to its original batter form.