system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5:If soap breaks down oil, why is the sebum in blackheads unaffected by washing your face?
gpt
Soap doesn't really "break down" oils.  It acts as a connector between water and oil.  Water is polar and oil is nonpolar.  Soap has a polar end and a nonpolar end so it acts as a hitch between the two and allows water to wash away with the oil attached.  If blackheads are too deep then they won't be pulled away by just water running over them cause they're stuck in there.