Pressure physics problems

[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