Scuba Diving

Many people think of scuba diving as just a swim in the water, but in reality it is a very exciting, dangerous, and potentially fatal sport and activity. There are many types of scuba diving, ranging from recreational to sport to career diving. Scuba Diving is just not a swim in the water, scuba requires certification, uses technical equipment, and there is a lot of risk involved with scuba diving.

Scuba, which is actually an acronym for "self-contained breathing apparatus",

Allows divers to dive deeper and stay submerged longer. Scuba comes a long way from other forms of diving by using an air-tank and regulator. This is what allows them to stay under longer and dive deeper. Scuba originally began with military and commercial applications, where it is still used today. But now, by far the largest group of divers is "Recreational Divers". These dives are practiced at depths of less than 130 feet, from these depths, divers can make a straight ascent to the surface. Diving beyond this limit requires advanced training. (Lawrence, 4)

Before recreational or sport divers can take a plunge into the water, they must complete a course in scuba diving and become certified. There are many scuba diving agencies, the largest being PADI, but there are many others, including the National Association of Underwater Instructors and the National Association of Scuba Diving Schools. All agencies require that participants be proficient swimmers, in reasonably good health, and at least 12 years of age. The course usually consists of classroom work, practice in a pool or confined body of water, and dives in open water. In the course, students learn to use diving equipment, to equalize air pressure as they descend, to swim efficiently underwater, to clear the mask if water leaks in, and to ascend safely. Because divers cannot talk to each other underwater, they also learn how to communicate underwater with hand signals. Scuba diving should always be practiced with at least one other person, and partners should remain together throughout the dive. Certification courses teach divers the rules and advantages of the buddy system. Diving partners learn to double-check each other's equipment, share a single air supply, and assist one another should a problem occur. Neutral Buoyancy is an important skill taught in certification class. Neutral Buoyancy is a state, in which the individual neither sinks nor floats. In this weightless state, a diver conserves energy and air and keeps diving equipment off the bottom where it could be damaged. To become certified, diving students must pass a written exam and a swimming proficiency test, and successfully demonstrate newly mastered skills in four open-water dives. Proficient divers then receive a certification card that allows them to make unsupervised dives, refill air tanks, and buy diving equipment world-wide. Stores that sell diving equipment and businesses that operate diving tours require this proof of certification. During the certification course, divers will learn everything about the technical equipment and how to use it.(Lawrence, 24)

Diving equipment depends on the location of the dive, but whether sport or recreational diving, divers need several basic items of equipment: a mask, a snorkel, fins, and when necessary, and exposure suit to remain warm, air-tank and regulator. The diving mask covers the nose and eyes and enables the diver to see while underwater. A snorkel is a tube that allows the diver to breathe while floating at the water's surface. One end fits in the diver's mouth and the other end extends above the water. The fins are worn on the feet of the diver, these help the diver propel themselves through the water with a smooth, energy-efficient motion. Wet suits are worn to keep the diver warm in warm-water temperatures and dry-suits are used in cold-water temperatures. A wet suit is made of Neoprene rubber and absorbs and traps a thin layer of water, which the diver's body heat quickly heats. In temperatures below 50 degrees, divers wear a dry-suit. To breathe under-water, scuba divers wear a metal tank filled with compressed air, and a regulator that attaches to the tank. The regulator reduces the pressure of the air to match the surrounding water pressure, so that the diver can breathe the air comfortably. The regulator also distributes the air among four hoses. One hose delivers air to a mouthpiece, through which the diver inhales and exhales. Another hose from the regulator attaches to an adjustable air bladder called a Buoyancy Compensator devise, which the diver wears as a vest. By adding air to the BCD, the diver becomes more buoyant and rises, by releasing air, the diver becomes less buoyant and sinks. With minor adjustments of air, the diver can achieve neutral buoyancy. A third hose attaches to pressure gauges that divers use to monitor how much air remains in the tank. A fourth hose attaches to a backup breathing device called an alternate source, or octopus. Divers also wear a belt with lead weights to help them descend and stay underwater. The weights are spaced evenly around the belt for balance. Most divers carry from 5 to 20 pounds of weight, depending on their body weight, the suit they are wearing, and where they are diving. A quick-release buckle enables the diver to shed the belt and rise to the surface in an emergency. Emergency equipment includes a dive knife, in case the diver becomes entangled in fishing line or marine plants, and whistles, lights, or signaling devices, in case the diver is lost or swept out in a current. Divers should also have a tank of oxygen onboard, along with a marine radio and a first aid kit. The diver should not only have knowledge of his equipment but a scientific knowledge of his surroundings underwater. (B&B Aquatic Adventures)

The key to understanding scuba diving is the concept of pressure, and how it varies with depth. Pressure is a force or weight per unit area. All matter, including air, has weight due to earth's gravity. Accordingly, anything exposed to air is under pressure-the weight of the atmosphere above it. This weight of air, due to gravity, is known as atmospheric pressure. Gravity keeps the atmosphere wedded to the earth. Without gravity, earth's atmosphere would float away to outer space. Since gravity diminishes with distance from the center of the earth, air weighs less at altitude than at sea level. Literally, air at altitude is "thinner" compared to at sea level, and air becomes progressively less dense with increasing altitude. The pressure under water can cause many hazards for any type of diver. (Reseck, 68)

Hazards associated with recreational diving stem chiefly from breathing air under pressure, though a few marine animals also pose hazards. Most hazards can