# Pressure of a snorkeler

1. Oct 28, 2007

### thatgirlyouknow

1. The problem statement, all variables and given/known data
The human lungs can function satisfactorily up to a limit where the pressure difference between the outside and inside of the lungs is 1/20 of an atmosphere. If a diver uses a snorkel for breathing, how far below the water can she swim? Assume the diver is in salt water whose density is 1029 kg/m3.

2. Relevant equations
1 atm = 1.013e5 Pa
1/20 atm = 5065 Pa
P1 + P2 = gauge pressure
P = density*gravity*height
P = Force/Area
3. The attempt at a solution

So the pressure in the lungs minus the pressure outside the lungs must be less than 5065 Pa. If
P1-P2 = 5065 and
P2 = 1029*height
these should just be combined somehow. However, how do I know what the pressure is inside the lungs? If I use 1 atm,
1.013e5 - 1029(g)(h) = 5065
96235 = 1029(9.8)(h)
h = 9.54 m
But this is not correct. Does anyone have a suggestion?

2. Oct 28, 2007

### Kurdt

Staff Emeritus
I would expect the pressure under water to be greater so I'd take the under water pressure away from the pressure in the lungs. The difference is not that great however.

3. Oct 29, 2007

### thatgirlyouknow

Ok so any other ideas?

4. Oct 29, 2007

### stewartcs

I came up with about 0.5 meters.