* Baking soda (sodium bicarbonate) is a base. It reacts with acids, producing carbon dioxide gas.

* Eggs contain acids. The most notable is the amino acid cysteine, which is responsible for the "sulfur" smell of cooked eggs.

* Reaction: When baking soda is added to eggs, it reacts with the acids, releasing carbon dioxide gas. This is what creates the fluffy texture in the scrambled eggs.

Key indicators of a chemical change:

* Formation of a new substance: The carbon dioxide bubbles are a new substance.

* Change in chemical composition: The eggs have undergone a chemical change due to the reaction with baking soda.

* Irreversible reaction: You can't easily get the original ingredients back (eggs without baking soda) once the reaction has occurred.

Therefore, adding baking soda to scrambled eggs is a chemical change.