How strong is air pressure?

An object with a one-meter-squared side experiences a little over a hundred thousand newtons of force, over that area, due to atmospheric air pressure.

If there were absolutely no opposing forces, such an object with a mass of only 1 kg would experience an acceleration of a little over 100,000 m/s^2.

Of course, it would be quite a feat to arrange a system in which the pressure did not change at all as the object were accelerated. Consider a potato gun or pneumatic rifle. As the projectile begins moving, the cavity behind it gets larger, and the pressure in that cavity is reduced. When fired with atmospheric pressure into a vacuum, the projectile would experience that 100,000 m/s^2 acceleration only instantaneously at the beginning of its movement; at all later times the acceleration would be much less.

Anecdotally, air pressure can store very large amounts of energy. A scuba tank exploding inside a dive shop, for example, can pretty much destroy the whole shop.

- Warren

 

You would not want to be in your body if the earth suddenly lost its measly 15 psi atmosphere. Your blood would boil, lungs collapse... and it gets ugly after that.