system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How do one-way mirrors work?
gpt
It's really just a window with tiny flakes of something reflective (Aluminuim or silver, for example) in it. When the other room has very bright lighting (and the observation room very dim) the window looks like a mirror because so large portion of the light comes reflected from your side.