Detecting whether a mirror is single- or double-sided is a valuable skill for various reasons. Double-sided mirrors, also known as two-way mirrors, have unique properties that distinguish them from regular mirrors.
One of the defining characteristics of a double-sided mirror is its ability to allow light to pass through one side while reflecting it on the other. This property makes double-sided mirrors useful in applications where observation is necessary without being detected, such as in interrogation rooms, surveillance, and security settings.