Why are there mirrors that from the inside you can’t see the outside, but from the outside you can see the inside?

Question

Why are there mirrors that from the inside you can’t see the outside, but from the outside you can see the inside?

In: Technology

Answer 1

These are called two way mirrors. There is actually nothing special about it as it is just a simple pane of glass. When light hits the glass about half of it is reflected and half of it passes through. But if you make sure that there is only light on one side of the glass there will be no light to pass through the glass from that side. This allows the people inside the room to look out but the people outside will just see their own reflection.