Pressure physics problems

[dlavery]

Originally Posted by Mike Betts

Sand,

Yes, atmospheric pressure is added in.

As a rough number, 1 atmosphere of pressure for each 33 feet of seawater (this is from my days as a scuba diver). So that at 100 feet of depth, the pressure is about 4 atmospheres. 1 liter of compressed air inhaled into the lungs at 100 feet will expand to 2 liters at 33 feet (2 atmospheres) and 4 liters of air at the surface (1 atmosphere). This is why it is absolutely essential for divers to constantly exhale during ascents and most "damage" from someone holding their breath while surfacing occurs in the last 10 feet...

Regards,

Mike

Mike -

Just a clarification. I seem to remember from my scuba (and a few other) classes) that overburden pressure increases of incompressible materials (e.g. pressure increases associated with increasing water depth) is linear. So in the example cited above, would it not be that 1 liter of compressed air at 100 feet will expand to 2 liters at 66 feet, and 3 liters at 33 feet, and 4 liters at the surface?

-dave