system
Given the following post, respond as if you're commenting on Reddit:
human
How exactly does soap get you clean?

What chemicals in soap react with what chemicals in the body? How does this make your skin clean? Any help would be appreciated- thanks!
gpt
Soap contains (generally) alkali metal salts of fatty acids, which are formed through the saponification reaction of triglycerides (which are a type of fats that we eat). These soap molecules are considered amphipathic; that is, they contain a hydrophobic nonpolar end, and a hydrophilic end. It is an approximation to say that dirt particles which cannot be washed off with water easily have some hydrophobic quality. When soaps are added to water, they form structures called micelles; these are balls of detergent molecules where the hydrophilic carboxyl termini of the molecules of the soap face out towards the water favorably, and the hydrophobic ends cluster together out of reach of water favorable. This is favorable because the interaction of hydrophobic tails with water is entropically unfavorable. Hence, these micelles allow the soap to solve hydrophobic dirt/dust particles that normally would not easily be solvated by water. These hydrophobic dirt molecules could be trapped inside the micelles. Thus, the soap allows us to "wash away" hydrophobic stuff that cannot easily be gotten rid of by water.