Question

The percentage of Oxygen in air is about 21%. But the oxygen cylinder meant to be carried by deep sea divers contains about 4% Oxygen. Why is there a difference in the percentage of oxygen.

Answer 1

1. Deep sea divers go in to the deep sea where the pressure is high due to the depth of the water.
2. As pressure increases, the solubility of oxygen in blood increases.
3. The requirement of oxygen for respiration does not increases as we move deep into the sea.
4. Therefore, the percentage of oxygen in the cylinder carried by them ought to be less (about 4 % oxygen):

That is why, there is a difference in the percentage of oxygen in air and the oxygen cylinder for deep sea divers.