system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What is that weird 'milk skin' that forms on top of milk after boiling it?
gpt
Proteins in the milk lose their solubility as the result of heat, and coagulate or come together to form a sticky film that floats on top of the liquid milk. It’s the result of the chemical transformation of those proteins caused by the heat. Biochemists call this process denaturation.