The pressure exerted by a fluid column with density p and
height h in gravitational field g is:
PFLUID pgh and g = 9.81 m s-2

The average density of air is 1.20 kg m-3 at sea level at 298
K. If the whole atmosphere had this density, how high would
the atmosphere be?

At what depth under water does the pressure of the water
equal 1.00 atm?