Book 13, Question 68
Why Can Some Windows Look Like Mirrors From the Outside in the Daytime?
Mirror-like windows have a thin metal coating that reflects some light and lets some through. Outside on a bright day, the reflection of the sky is brighter than the dim light coming from inside. So the window looks like a mirror from outside.
More fun facts
- A half silvered mirror reflects some light and lets some light through at the same time.
- In a University of Colorado demonstration, a volunteer's reflection slowly turns into a monster mask as the lights inside a box behind the mirror get brighter.
- With the box lights at full brightness, the mirror mostly shows what is behind it, and the volunteer's own reflection fades away.
- With the box lights off, the mirror acts mainly as a reflector and the mask stays hidden in darkness.
- At in between brightness, the mask and the volunteer's reflection appear on top of each other.
- The demonstration shows that the relative brightness of the light on each side determines which image you see.
Sources: Colorado
Questions kids ask
Can people inside see out of mirror windows?
Yes. During the day the inside is dimmer, so people inside can see out while people outside see a reflection.
What happens to a mirror window at night?
If the lights are on inside, it flips: people outside can see in, and people inside see reflections.