SIT TIME 
| In between our dives we took the boat to shore and hung out for an hour or so to accomodate the sit time in our dive table. For those of you who are non-divers, this means you have to chill for a bit and let your body breath off some of the residual nitrogen that builds up when you breath air under depth at increased pressure. Here's some more detail. When you breath from a SCUBA tank, the air in your lungs at a 33 foot depth has twice the pressure of air on land. At 66 feet it has 3 times the pressure. At 99 feet it has 4 times the pressure, and so on. When high-pressure gases in the air come in contact with water, they dissolve into the water. This is how carbonated beverages are made. To make carbonated water, water is exposed to high-pressure carbon dioxide gas and the gas dissolves into the water. When you release the pressure in a bottle of soda - bubbles suddenly start rising. The gas dissolved in the water at high-pressure comes out of the liquid when the pressure is released, and we see it as bubbles. |
 Sitting out between dives |
 Luckily no one had to go in there... |
If a SCUBA diver stays under water, say at a depth of 100 feet, for a period of time, some amount of nitrogen from the air will dissolve in the water in his/her body. If the diver were to swim quickly to the surface, it is just like uncorking a bottle of soda - the gas is released. This can cause a very painful condition, and it is sometimes fatal. To avoid the effects of quick decompression, the diver must rise slowly so the gas can come out of solution slowly. If the diver does rise too fast, the only cure is either to go back down (which is like putting the cap back on a bottle of soda - the bubbles stop), or to enter a pressurized chamber, or hyperbaric chamber, in which the air pressure matches the pressure at depth. Then the pressure is released slowly. Decompression sickness, also known as the bends, is one danger of diving. Other dangers include nitrogen narcosis, oxygen toxicity and simple drowning (if you run out of air before making it back to the surface). |
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Cozumel Trip Index: Cozumel Home Snorkeling On the Boat In the Water Sit Time Town and Island Celebration Party |
 Safely waiting for the next dive! |
jennifer home
