My kid asked my this today, and I need the doper masses to help me answer it.
Why is it when he (as well as I) dive down to the bottom of the pool at 12 feet we suffer intense ear pain. I know its the pressure, but how can scuba divers handle it? Do your ears get conditioned to it?
No, you don’t just get used to it. One of the things you learn in scuba class is how to clear your ears as you descend. It’s not hard-- the same technique you’d use when descending at the end of an airplane flight.
For every 33 ft you descend in water, you add one atmosphere of pressure.
In scuba, you breathe pressurized air. The regulator adjusts the pressure of the air you are breathing so that it equals the water pressure. Thus, you can equalize the pressure in your ears, sinuses, etc. Otherwise, very bad things would happen–eardrums burst, sinuses fill with blood, etc. Thus, you are never supposed to go diving when you are congested or have a cold, b/c you can’t equalize the pressure in your ‘air spaces.’
He can equalize his ears by holding his nose and blowing through it. This will equalize the pressure and the pain will go away instantly.
The pain you feel as you dive down is a result of your eardrum deflecting due to the pressure differential (increased ambient pressure versus atmospheric pressure in the middle ear). As long as this differential is maintained, you will continue to feel discomfort. The way that divers circumvent this problem is by equalizing the middle ear pressure with the ambient pressure, returning the eardrum to its normal undeflected condition. The middle ear is connected to the sinus cavities by means of a small passageway called the Eustachian tube. Normally, this passage is not maintained clearly at all times, but may be forced open by articulating the jaw, or performing a Valsalva maneouver in which the nose is pinched closed, and you exhale gently against it - this causes a pressure increase in the sinuses which will tend to open the Eustachian tube, bringing the middle ear pressure up and relaxing the eardrum.
He will likely need to clear his ears again when he comes up as well. FYI.
For a quick dive to 12ft, I don’t bother with the clearing. (Snorkel, or freedive) I’ll be back long before it would become a problem, and I don’t like to have to clear my ears twice, nor use my hand to pinch my nose, rather than providing propultion at depth.
When SCUBA diving, I clear as soon as I feel ANY pressure, as it’s much easier to clear 2 small blocks, than to clear one large one.
-Butler
Just to be nitpicky…
33 feet of sea water equals one atmosphere.
34 feet of fresh water equals one atmosphere.
In addition to holding the nose and exhaling, you can open the Eustachian tubes by yawning. Of course yawning with your mouth closed would be desirable underwater.
For me, this seems to work OK when ascending, but doesn’t work at all when descending.
Another option (that I’ve never tried, learnt about it in scuba class) is moving your jaw back and forth.