# Air pressure difference in inside and outside of house

1. Jan 12, 2010

### fsb257

Pressure is defined like FORCE/SURFACE [Pa] so the outside pressure close to the earth is atmosphere pressure (101 325 Pa) defined by the mass of air/surface.Why is the same pressure in my house? There isn't much air like in outside...Thanks for the potential answer an sorry for the bad english.

2. Jan 12, 2010

### mgb_phys

Good question, should be asked by anyone who thinks about air pressure.

Air pressure of 100kPa is about 10 tons/m^2
The walls of your house can't withstand this sort of pressure, the are like the soft walls of a balloon.
So the huge force of the air pressing down on the roof also presses down on the air inside to give the same force.

Picture the air like a pile of bricks on a weighing scale, now put a thin piece of paper between two of the brick to represent the roof of the house, it doesn't change the weight on the scale.

3. Apr 4, 2010

### cragar

If i put a bathroom scale on the bottom of a pool , would the scale read greater less or the same , it would read the same .

4. Apr 5, 2010

### pallidin

Not if you're standing on it.