Why doesn't air pressure crush human beings standing at sea level?

Answer 1

Millions of years ago, there were two kinds of life on Earth:

-- One kind had bodies that had no internal pressure pushing outward.

-- The other kind had bodies with internal pressure, which pushed outward

and canceled the inward atmospheric pressure.

The first kind of life only lasted about 3 minutes, before it was totally squashed into

extinction by atmospheric pressure. Hence, that kind didn't last long enough to be

fruitful and multiply, and the only kind of life that remained on Earth was the kind

with internal pressure to balance atmospheric pressure and avoid getting crushed.

Some examples of that kind of life on Earth today include elephants, cats, ants, birds,

snakes, and human beings. In fact, every form of life on Earth today is descended

from the first ones that were smart enough to develop internal pressure to push

back against the atmosphere.

That may sound perfect, but it's not all good. In these modern times, at the dawn

of the Space Age, it means that when we go into space, we have to wear these

bulky, ugly space suits, that have atmospheric pressure inside them. If we don't,

and we go into space anyway, where there's no atmospheric pressure, we blow up

like a balloon.

Answer 2

because there isn't all that much more pressure outside of the body than there is inside. there is only 14 pounds of air presure at sea level. why can fish swim at the bottom of the sea.