Scuba Diving is a sport where people (called "scuba divers", or simply "divers") can swim underwater for a long time, using a tank filled with compressed air. The tank is a large metal cylinder made of steel or aluminum.
History[change | change source]
In the 1600s, a diving bell would be lowered that had trapped air in it. A diving bell is like a large heavy upside-down bucket that holds air inside when lowered into the water. A diver would breathe that air and swim in an and out of the bell to work until the air became bad. Later fresh air was pumped to the diving bell through a hose.
The first diving suits used a heavy copper diving helmet with windows and a hose attached to an air hose. Divers would walk on the seafloor as it was not safe to swim. The air hose would send air to the helmet from a pump on land or on a boat above the diver.
Jacques Cousteau was a Frenchman who developed several important parts of the scuba system and made it useful. One part was a better regulator that only sent air when the diver breathed in. This let the divers go farther on one tank. It was light enough to use with fins and easily swim. He also took many underwater movies and showed people what was under the water and why it needed to be protected.
Equipment[change | change source]
- Scuba tank, (one or more) containing air. The air is ordinary compressed air for most dives, but deep dives use a mixture of air with more oxygen to avoid decompression sickness, also called the bends (a painful or deadly problem from going to the surface too fast).
- Regulator for breathing the air from the tank. This reduces the pressure of the air coming from the tank. It adjusts the air to the pressure of the water around the diver so they can breathe easily at any depth.
- BCD (buoyancy control device) to control whether the diver floats or sinks. The diver can add air or remove air by using dump valves or an inflator on their regulator. Divers may also wear weights so they are neutral (float in place) at a depth they want. If the diver swims upward the air in the BCD will expand and the diver must let some out or float to the surface. If the diver swims down the air will compress and the diver must put in more air or sink to the bottom, so the diver must carefully control how much air is in the BCD.
- Depth gauge, to know how deep they are. There is also an air gauge to know how much air is left in the tank, and there may be a watch to tell the time or a dive computer to show how slowly they must come up to be safe from decompression sickness. A safe dive depends on how long and how deep the diver goes, and how long it has been since the last dive.
Divers also use snorkeling equipment. They wear a mask to see through, a snorkel for breathing at the surface, fins on their feet to swim better, and a wetsuit to keep them warm under water because water makes you cold four times as fast as air.
Certification[change | change source]
Running out of air or getting the bends can be dangerous. So a person must be trained to use the equipment and dive safely before going scuba diving. When they show that they can dive safely they get a certification card to show that they know how to dive safely to the standard shown on the card. The biggest organization for certifying divers is PADI - Professional Association of Diving Instructors - but there are many others, depending on the country. Some tourist places have a short course without certification and then the instructor will lead the diver in a shallow dive, all in one day.
Because of special dangers, there are advanced classes for things like diving in or around underwater ship wrecks, cave diving, and deep diving (more than 60 feet or 18 meters).
Related pages[change | change source]
- free diving - Diving without scuba equipment (holding your breath). Snorkeling equipment is often used in free diving. No certification is needed but it can still be dangerous.