Doors and windows????????

Question

Why is it easier to close a bedroom door when the window in your room is open?

Answer 1

The large surface area of the door has atmospheric pressure acting on it on both sides.

As you close the door into a room with the window closed, the door is pushing a large volume of air into the room. This increases the room pressure very slightly which pushes back against the door's large area making it harder to close.

With the window in the other room open, as the door is closed, the air is displaced to the outside therefore preventing the room pressure from  increasing...The door closes easily.

Answer 2

because there's somewhere for the air to go.

people who owned old VW beetles had that problem.

with a window open, the door closed easily.

with no window open, you had to slam it pretty hard.

and what would happen is that you got used to closing the door with no window open, and when you didn't notice an open window, the door slammed pretty hard, because the air resistance that you were expecting wasn't there.