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What Is Scuba Diving?

Updated on April 15, 2013
Scuba diver at one with the ocean
Scuba diver at one with the ocean | Source

What does SCUBA mean?

This was originally an acronym for self-contained underwater breathing apparatus but is now just used as a word in its own right. It refers to the equipment a diver uses to be able to breathe underwater which usually consists of a tank of compressed air, a mouthpiece, regulator and some sort of harness to attach it all to the diver. This harness usually takes the form of a jacket that can be inflated or deflated to help with buoyancy control and as such is called a BCD or Buoyancy Control Device.

What does a scuba diver wear?

Depending on the warmth of the water, the diver may wear a suit for warmth. This could be a wet suit, semi-dry suit or dry suit. The wetsuit could be a spring suit or shorty which covers the body but has short arms and legs, or a steamer, which also covers the body but has long arms and legs.

A semi-dry suit has tighter seals around the wrists, ankles and neck so that once water is inside the suit it can be kept there which allows the body to heat it up and keep it as a layer of warmth throughout the dive. A dry suit is completely sealed so that the diver has no water next to his or her body at all and is used for very cold water.

The wetsuit and semi-dry suit also come in different thicknesses for different temperatures or water, the thicker they are, the longer the diver will be able to stay in colder water. There is a limit obviously to the thickness of the suit as if it is too thick the diver will not be able to bend his arms or legs!

As well as the suit, the scuba diver will wear fins on his feet, a mask (that covers the eyes and nose) with a snorkel, a BCD as explained earlier with the tank and regulator attached. The mask needs to cover the eyes because of the refractive index of the water. It is different to that of air and means that if the diver had no mask on at all, everything would be blurred.

As there is a small pocket of air in front of the eyes, this allows the diver to see more clearly although there is a magnification of all that he can see. Everything looks bigger and closer than it actually is. The mask has to cover the nose because air pressure changes as the diver descends under the water.

When the pressure increases, it makes any gases shrink. Therefore, the size of the air inside the mask will shrink causing the mask to be sucked onto the face leaving a pressure mark. As the diver descends he needs to breathe air out of his nose into the mask to counteract this. As he ascends at the end of a dive, the air will expand and any excess will safely leave the mask out of the side as bubbles.

The regulator is a piece of diving equipment that changes the compressed air’s pressure (which is very high when it is in the tank) and reduces it so that it can be breathed in by the diver at the same pressure as he is experiencing at the mouthpiece. Breathing in highly compressed air would be very dangerous.

What does a scuba diver do?

To start a dive, the scuba diver will descend under the water until he reaches his required depth. At this depth, air can be put in his BCD from the tank he is carrying to equalise his buoyancy which means he could float at that particular depth without finning (kicking his feet). This means that he has less work to do to propel himself along as he is not trying to fin to stay at a certain depth rather he is just using his energy to go forward.

As he descends, he must breathe out through his nose periodically as explained earlier to prevent mask squeeze. Returning to the surface is a far trickier manoeuvre. There is a risk of the bends if ascending too fast. This is because nitrogen bubbles, which are absorbed into the blood while breathing underwater, are increasing in size as do all gases. If the diver is ascending too fast, they do not have enough time to dissipate and will increase in size enough to cause pain in the joints when they are too big to pass around the veins and arteries.

This can be lethal if the bubbles reach the brain or heart. The only cure is to increase the pressure around the diver again and then return to normal pressure very very slowly. This is done not by returning to the diving depth but in a hyperbaric chamber under medical supervision. If the diver descends at a correct speed, he should be safe from contracting the bends, but it is advisable to stop about 5 metres under the surface for 3 minutes just to be sure.

learn to scuba dive safely
learn to scuba dive safely | Source

Why go scuba diving?

Even though there are dangers associated with diving, the sights that can be seen are incredible whether you are interested in the flora and fauna or magnificent coral structures (I know, technically they are fauna too) there is a lot to see under the world’s oceans. There are also specialties that can be learnt to increase the interest, for example, cave diving, underwater photography, wreck diving, night diving etc.

How to learn to scuba dive

If you are interested in learning to dive, there are many places that can teach you but make sure they are properly certified. These include PADI – Professional Association of Diving Instructors, NAUI – National Association of Underwater Instructors, ACUC – American Canadian Underwater Certifications, SSI – Scuba Schools International and BSAC – British Sub Aqua Club.


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    • writerbeth profile image

      writerbeth 4 years ago from England

      I have the same problem with the deep water, particularly if there are supposed to be sharks around (diving in the Great Barrier Reef was fabulous and really really scary all at the same time!). I much preferred the shallower dives, plus you can stay longer underwater if your maximum depth is less. It's a win win situation!

    • tomstravels profile image

      Thomas Caton 4 years ago from the business end of a strong wind

      nice hub, though really deep water scares the *&^% out of of me, perhaps one day...

    • writerbeth profile image

      writerbeth 4 years ago from England

      I can definitely recommend it, trouble is, once you get the taste for diving, say goodbye to all your cash - you won't want to do anything else!

    • Vacation Trip profile image

      Susan 4 years ago from India

      Yes it sounds very adventurous and would love to go.

    • writerbeth profile image

      writerbeth 4 years ago from England

      My pleasure, glad you enjoyed it. The million dollar question now is - do you like the idea of having a go yourself?

    • Vacation Trip profile image

      Susan 4 years ago from India

      Interesting Hub. Came to know so many things that I was not aware of. Thanks for sharing.