system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why does aluminum foil have 1 side shinier than the other?
gpt
I saw this on how it's made once. Once of the final steps in rolling the foil thinner and thinner would tear a single layer of foil, so they roll two layers together. One side gets rolled against a huge roller, and the other against another layer of foil. One of those sides ends up shiny (I think it's the one against the other layer of foil), and the other dull.