Why do cookies dissolve in milk?

Cookies don't technically "dissolve" in milk the way sugar does. Here's what actually happens:

* Water Absorption: The main ingredient in milk is water, and cookies contain various ingredients like sugar, flour, and butter that readily absorb water.

* Softening: The absorbed water softens the cookie's structure, making it more pliable and less crunchy.

* Breakdown: The milk's warmth and the process of softening can also break down some of the cookie's components, like starches, making it even more mushy.

* Dissolving of Sugars: Some of the sugar in the cookie will dissolve into the milk, making it sweeter.

So, while the cookie doesn't disappear entirely, the combination of water absorption, softening, and partial breakdown results in a softened, mushy texture that may appear like it's dissolving.