How doeS matter change in chocolate chip cookies when baked?

Here's a breakdown of how matter changes in chocolate chip cookies when baked:

1. Flour:

* Raw: Flour is made of starch granules and protein molecules (gluten).

* Baked: When heated, the starch granules absorb water and gelatinize, becoming translucent and sticky. This creates the chewy texture of the cookie. The gluten proteins also develop, creating a framework for the cookie.

2. Sugar:

* Raw: Sugar is in a crystalline form.

* Baked: The sugar dissolves in the water in the batter, and then caramelizes during baking. Caramelization contributes to the brown color and sweet, complex flavor.

3. Butter:

* Raw: Butter is solid, containing water, milk solids, and fat.

* Baked: The fat in butter melts, which creates a tender and moist cookie. The milk solids brown and contribute to flavor. The water evaporates, aiding in the browning process.

4. Eggs:

* Raw: Eggs contain protein, water, and fat.

* Baked: The proteins in the eggs coagulate (solidify) during baking, giving the cookie structure and adding to the chewy texture.

5. Chocolate Chips:

* Raw: Chocolate chips are solid and relatively hard.

* Baked: The chocolate chips melt slightly during baking, creating a gooey center while the outside remains firm.

6. Baking Soda and Baking Powder:

* Raw: These leavening agents are in their inactive form.

* Baked: The heat activates the baking soda and baking powder, causing them to release carbon dioxide gas, which makes the cookies rise and become fluffy.

Physical Changes:

* Shape: The dough spreads and flattens during baking.

* Color: The cookies become brown due to caramelization of sugars and browning of milk solids.

* Texture: The cookies become firm, chewy, and crispy, depending on the recipe.

Chemical Changes:

* Caramelization: Sugars caramelize, creating new flavors and color.

* Maillard reaction: The browning of sugars and proteins, contributing to flavor and aroma.

* Gelatinization: The starch granules in the flour absorb water and swell, becoming translucent.

* Protein coagulation: The proteins in the eggs and flour solidify, providing structure.

In summary, baking cookies involves a series of physical and chemical changes that transform raw ingredients into delicious treats.