SCUBA+Diving

Buoyancy is how much an object may sink or float depending on its weight and volume. When an object floats at surface level it is referred to as positively buoyant, while one that sinks continuously would be negatively buoyant. When the object stays at a certain level in the water it is neutrally buoyant. When diving, it’s important to regulate one’s breath because our lungs are our built in buoyancy system. By breathing we can control slight differences in buoyancy in order to be neutrally buoyant. The BCD (buoyancy control device) allows us to control buoyancy at larger proportions than we can control in order to be positively or negatively buoyant at given times.
 * __Scuba Diving Guide__ **
 * Buoyancy: **

Water pressure is an important factor when diving because it determines how much time one can be underwater. A scuba tank is made up of 21% oxygen and 79% nitrogen, almost exactly the same as our atmosphere. As pressure increases, the space in the tank decreases, but the amount of air you have is the same. Because of this, you breathe more air at a time which reduces the amount of time you can use the tank, and simultaneously creates a new variable. The nitrogen we breathe in our usual atmosphere has somewhere to go to, but underwater it doesn’t so it goes into the bloodstream. In high quantities, this is toxic for the human body, which is the main reason time underwater is limited. This nitrogen quantity stacks with each dive unless there is a break of 24 hours (which is what it takes to clean the blood stream). Proportionally, every 10 meters of depth adds 1 bar/ata of pressure to the tank. For example, 20 m are 2 bar/ata of pressure, which leaves the tank with half the volume of air and twice the density. This means the tank will last for half as long.
 * Effects of Depth Increasing Pressure: **

Depth also affects the human body aside from nitrogen in the blood stream. Pressure affects all areas that contain air in the body. The least perceived area, but probably most important, would be the lungs. Pressure compresses them and the air they have, but you keep breathing normally, which is dangerous. If you hold your breath underwater the change in pressure will expand the air in your lungs and that may cause a rupture. Therefore, the most important rule when scuba diving would be to breathe constantly. If one were forced to leave the regulator, then the solution would be to exhale slowly until aid comes or one is forced to leave the waters. The more apparent area would be the ears. The deeper, the more pressure one will feel in their ears. To do this one must equalize before going any deeper and do so every meter. To equalize, one must close their nose and blow to send air from the lungs to the ears. Do so slightly or the ears may suffer damage, but if not done enough times, the ears will suffer as well.
 * Effects of Depth on the Body: **

Tells you how much air is left in your tank in psi units. Holds the tank that straps to the body and has buoyancy control mechanism, emergency regulator, primary regulator, and a submersible pressure gauge. Depending on the temperature of the water and how deep you are, these suits keep you warm and prevent hypothermia, which may contribute to decompression sickness. It should fit you like comfortable shoes, not too tight and not too loose. These help you swim faster and comfortable underwater. These are two of the most important things for scuba diving. The mask has a bubble of air so that you can see underwater and a flexible part in the nose so that you can equalize the pressure in your ears. The snorkel is essential for swimming in the surface. It takes the high pressure from the gas and makes it breathable. Make sure you have two of these in case the first one breaks down. It is where the air is stored and allows you to breathe through the regulator. Hand Signals:
 * Equipment: **
 * Submergible pressure gauge: **
 * BCD (buoyancy control device): **
 * Wetsuit/Drysuit: **
 * Fins: **
 * Mask and Snorkel: **
 * Regulator: **
 * Tank: **


 * Bibliography:**
 * //Open Water Diver Manual. // Rancho Santa Margarita, CA: PADI, 1999. Print.