BRAINBOX PROBLEM SOLVING - QUICK-TRICKS

How can you tell if a wind is blowing inside a box

The box has five doors (one on each side and on the top).

You can pass a things between any of the doors but:

1. the box is made of thick metal and you cannot see into it (it is like a safe)
2. you cannot measure the wind while any of the doors are open.
3. you cannot communicate in any way with the anything in the box when the doors are closed
4. your device cannot use a device that measures and stores the result and read it later.

How can you tell if a wind is blowing inside the box?

And while your thinking, here's a story about cats: https://www.youtube.com/watch?v=IOYyCHGWJq4