Quote:
Originally Posted by bigrobwoot
I never claimed to be an expert on scuba diving, don't get mad, I'm just trying to understand. I don't see how this test is the same as scuba diving. Are you saying that the air you breathe in while scuba diving increases in pressure as you dive deeper?
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Put it this way. If you have a balloon with 1 cubic foot of air in it and drag it down to the bottom of a 10' deep pool, that balloon would go from the size of a basketball to the size of a baseball. All the extra pressure from the surrounding water compresses the air inside the balloon.
So, to inflate that balloon to the size of a basketball under 10' of water, it would take a lot more extra air, right? That's exactly what happens to your lungs underwater when scuba diving. All the water pressure outside your body compresses you and your lungs, requiring you to breath compressed air in order to be able to fill up your lungs all the way when you inhale. In fact, if the air weren't compressed, you wouldn't even be able to inhale because your diaphragm isn't strong enough to counter all the water pressure if the air you're sucking in wasn't "as thick" as the water.
Now imagine what happens to that balloon underwater that's been filled up w/ compressed air to the size of a basketball when you let it float back to the surface. Without all that water on the outside of the balloon pushing on the air inside the balloon, the balloon expands and pops. That's what the bends is. When you're underwater breathing all that compressed air your blood stream ends up with compressed oxygen/nitrogen/etc in it. If you rapidly return to the surface, all those little "balloons" of compressed air in you expand and kick your ass. That's why you have to return to the surface slowly and reduce the compression level of the air you're breathing as you go so by the time you're back to the surface, you've swapped out all the compressed air in your blood for uncompressed air.
If you can't gradually ascend, that's when they have to toss your ass in a hyperbolic chamber and crank up the air pressure to the same air pressure of the compressed air you were breathing underwater. It's like putting you back under water w/o the water. Then gradually let up that air pressure to keep you from dying.