Chapter 17, Problem 85GP

Snorkelers breathe through short tubular “snorkels” while swimming under water very near the surface. One end of the snorkel attaches to the snorkeler’s mouth while the other end protrudes above the water’s surface. Unfortunately, snorkels cannot support breathing to any great depth: it is said that a typical snorkeler below a water depth of only about 30 cm cannot draw a breath through a snorkel. Based on this claim, what is the approximate fractional change in a typical person’s lung volume when drawing a breath? Assume, in equilibrium, the air pressure in a snorkeler’s lungs matches that of the surrounding water pressure.