physics
posted by Erin .
It is reasonable to assume that the bulk modulus of blood is about the same as that of water (2.20 GPa). As one goes deeper and deeper in the ocean, the pressure increases by 1.0*10^4 Pa for every meter below the surface.
If a diver goes down 33.0 m (a bit over 100 ft) in the ocean, by how much does each cubic centimeter of her blood change in volume? How deep must a diver go so that each drop of blood compresses to half its volume at the surface? Is the ocean deep enough to have this effect on the diver?

Compute the pressure change at depth of 33.0 m. It's about 3.3 times higher than the pressure at the surface
(density change)/density = change in pressure)/E
Where E is the bulk modulus. It's going to be a very small number: roughly 10^5.
For the last part of the question, set
(density change)/density = 0.5 = P/E, and solve for the required pressure and ocean depth.