Why are bubbles observed under the car door

Why does my door close faster when the window is open?

As the door approaches the door frame, it reaches a point where the door effectively closes the air in the room from the air outside the room for a moment. This only happens for a moment as most doors are not 100% airtight. If this happens when the door is closed further, the air in the room will be decompressed as the volume of the room increases as the door closes further but the amount of air in the room does not change as the room is briefly sealed from outside the Space. There is thus a difference in air pressure across the door, with the greater pressure coming from outside the room. This greater pressure slows the door down just before it closes.

On the other hand, when the window is open, air is let into the room, and although the volume of the room increases when the door is closed, the air pressure from outside the window pushes air into the room to keep the air pressure in the room about the same as outside. There is no air pressure differential across the door that does not slow down.

It is also possible that a fan or something inside the building could create a lower air pressure inside the building and thus a small flow of air from the window into the building that would push the door to close any of the above described more quickly a short seal of the room, reducing the volume of the "Slam!" is increased.

Brandon Enright

I think you have the pressure and airflow to the rear for a door that closes a room.


I am thinking of a door that closes in a hall so that the door opens into the room and the window is also in the room.