Atmospheric pressure is supposed to be very large. Then why is it that we, along with everything else on the earth, do not get crushed under this tremendous pressure?
Asked by: Chinu
You are correct about the fact that atmospheric pressure is very large. Indeed, some would say
that it is very, very, very large! I guess you know that at sea level that pressure is 14 pounds
for every square inch of our body surface area. I don't know about you, but, for me that is a
very, very large area!
We are not crushed by this tremendous pressure because we grew up in it. I mean from the very
beginning of life on Earth, life grew up in this huge pressure. If we are being pressed inward by
this very large pressure we must be pushing out with an equal pressure. This is how all life on
earth evolved. In fact, we push out all the time. I am sure you have seen movies in which some
characters are pushed out into space. If the movie is done correctly you will see the persons body
continue to push outward without anything pushing back. Thus the person explodes! The movie
'Total Recall' has some especially good shots of this happening on Mars, where the pressure of the
atmosphere is much less than Earth's.
Now, if you want to see something get crushed under the pressure of a fluid you can go deep into
the ocean. Water pressure is much greater than air pressure. Humans can go only a couple of
hundred feet, with training, deep before the pressure of the water is more than our bodies can
bear. But, you know that there are creatures that can live at great depths without getting
crushed; and now you know the reason why.
Answered by: Tom Young, M.S., Science Teacher, Whitehouse High School, Texas
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'Physics is mathematical not because we know so much about the physical world, but because we know so little; it is only its mathematical properties that we can discover.'