WHAT IS SCUBA?
A SCUBA consists of 3 main equipment:
A regulator takes the compressed air from the tank and reduces the pressure of the air. This enables the the diver to breath normally and comfortably just like you are breathing in your life on land.
A tank can be made of steel or aluminum. It contains air (not only oxygen but oxygen, nitrogen and few other gases). The only 3 differences between the air that diving tank contains and the air that you breath everyday are:
Tank contains higher pressure (200 atm) than air that you breath in your life (1 atm on sea level)
Tank has cleaner (filtered while loading from the diving compressor) air
The air in the tank has no moisture (not to have water on the bottom of the tank and harm the tank in a long time of period)
BCD, the Buoyancy Control Device is just like a jacket. You wear it easily. The diver takes air from the tank and rises in the water. Vice versa, the diver releases air and descents. The logic behind a BCD is similar with the submarines. As you know, submarines pump water to their tanks to be able to descent and vacuum this water out to be able to ascent. BCD is very handy to be able to stay in every position while diving. You can even hover on any depth by using a BCD.
BCD, the Buoyancy Control Device minimizes the risks by giving the diver a chance to raise or descent whenever needed. Before divers have started to use BCDs, the risk and the accident rates were much more higher than it is today.
To learn more about buoyancy underwater, please read my article: Buoyancy Underwater: Tips For Perfect Buoyancy.
We also use:
Knife: To be able to help ourselves and our buddies (diving partner) in case of entanglements
Mask: To be able to see underwater. Humans are not designed to see underwater
Snorkel: To be able to breath comfortably before and after a dive. Before the dive on the surface, a snorkel helps us saving air and after dive, a diver can breath easily while swimming towards the diving boat/shore especially if there are waves.
Fins: Divers should use fins to be able to push themselves underwater.
Suit: To get protected from cold, scratches and even sun burn in summer.
Alternate Air Source (Octopus): To share air if your buddy is out-of-air.
Depth Gauge: To see the current depth
Pressure Gauge: To know how much air you have in your tank in terms of atm, bar or psi.
Dive Computer: To get the information about the depth, temperature, total time of the dive, ascent speed, how much time can you spend on certain depths and etc.
Torch: As a light source especially in night dives and deep dives. can also be used while looking in caves.
SCUBA is an extreme sport because human-being should not be underwater. We have lungs, not gills! But divers are demolishing this. In SCUBA diving, a diver is in a place that he/she in not designed to be.
SCUBA diving gives you the chance of being absolutely free! You can move anywhere you would like to: left, right, up, down.. Better, a diver feels like an astronaut because there is almost no gravity for him/her.
There are dozens of different colors and marine animals, as well as corals, caves and sponges. A great way to observe and get relaxed.