When you visit hotel rooms,dressing rooms and bathrooms, do you ever wonder if the mirror on the wall is a two-way mirror? 
There are a few tests you can do to make sure that it is not a two-way mirror.

These tests are easy to do and you will feel a lot safer just by knowing them.


1.This is how the fingernail test works: 
You place the tip of your fingernail against the surface and if there is a gap between your fingernail and the image of the nail, it is an ordinary mirror.
If your fingernail directly touches the image of your nail, then it is a two-way mirror.

2.Two-way mirrors are not hung on walls,they are set into walls or doors.
If there is a wall behind the mirror you can be sure it is an ordinary mirror, because a two-way mirror would be part of the wall.

3.Tap on the mirror,if it is an ordinary mirror it should produce a dull thud.
A Two-way mirror has an open space behind it, so when you tap on a two-way mirror it should produce a much more open and hollow sound.