The finger test: How to tell a regular mirror from a two-way mirror?

REAL MIRROR (Regular Mirror): There’s a gap between your real finger and the finger reflected. TWO-WAY MIRROR (Two-Way Mirror): The two fingers touch without a gap. The text below warns: Be careful in hotel changing rooms, malls, and shops. Brief scientific explanation: Regular mirror: The glass is thick, and the reflective layer (silver) is on the back. Light refracts the glass twice, creating a gap. Two-way mirror: The glass is thin, and the reflective layer is on the front. It’s