Rule Number 1

So in light of my mother finding another article outlining why I should not SCUBA dive, I would like to put up a post every once in a while explaining why putting on a giant rubber suit, strapping 60 pounds of gear on my back and proceeding to breath underwater for anywhere from 30 minutes to several hours is merely an absurd idea and not a dangerous one.

Rules of diving:
Rule number 1: Never hold your breath (mostly for ascending, just easier to remember this way)
This was the first rule Lance told us when we started our Open Water class. It was probably because it was the one that applied to us standing in 3 feet of water. Reasoning behind it is while underwater, you are breathing compressed air. The air then enters your lungs at a pressure corresponding to the depth you are diving at. For those of us who have had physics or fluids or thermodynamics lately, for a gas PV=nRT. n (number of moles of gas), R (Universal Gas Constant), and T (Temperature) remain constant throughout this whole process (negligible differences, so it's a safe assumption). Therefore Pressure and Volume are inversely proportional at all times.

When standing at sea level, the atmospheric pressure is appx 101 kPa, 1 atm. That is caused by the weight of about 80 miles of air stacked on top of us. Now water, being about 1000 times denser than air, exerts much more pressure than air as we descend through it. For this reason, we reach a pressure of 2 atm at 33 feet below the surface of the water. That means the 33 feet of water above us is exerting the same weight on us as the 80 miles of air above it. It also means that the same amount of air at 33 feet takes up half as much space as it did at the surface. By the same logic, if you fill up your lungs at 33 feet (represented by a balloon), when you ascend to the surface holding your breath, the volume doubles and, as succinctly put by my instructor, Lance Briner, "Pop, pop."

In conclusion, don't hold your breath, it's bad. That's kind of why it's rule number one.


SO, there's your first lesson on things that I've learned and now have zero ability to forget that keep me safe while I'm underwater. There will be more posts, perhaps tonight if I can't sleep. I fly out to El Salvador in 30 hours, so I'm rather excited right now.

Dive safe.

-Z