I'm Steve Ember. And I'm Barbara Klein with EXPLORATIONS in VOA Special English. Today we explore the clear blue waters around the islands of the Bahamas to learn about the exciting sport of scuba diving. The word "scuba" stands for self-contained underwater breathing apparatus. Knowing how to dive opens up an entire underwater world of coral, fish, and other creatures. Join us as we learn the basics of diving, talk to an expert, and say hello to a shark.

Imagine swimming in clear blue waters as you look at small, brightly colored fish and the striking shapes of coral organisms. The underwater world is quiet except for the sound of your breathing. When you breathe out, you see many shining air bubbles floating upwards towards the surface of the water.

Since humans are not designed to see and breathe underwater, scuba diving requires several pieces of important equipment. Scuba divers must wear a mask in order to be able to see underwater. The mask creates an air space that protects the eyes and nose.

Scuba divers breathe with the help of a regulator, which brings air to the mouth when they inhale. The regulator is attached to an air tank that is placed on the diver's back.  There is an extra regulator called an octopus, which is used in case of emergency situations.

Divers also wear a BCD, or buoyancy control device, to control how much they float or sink. A pressure gauge device tells divers how much air is left in the air tank. Or, a dive computer can calculate how much air is left as well as a diver's depth and the length of time he or she can stay underwater.

Divers wear scuba fins on their feet to help them move easily and quickly through the water. Many divers also wear a wetsuit in order to stay warm underwater.

To learn how to use all of this equipment, it helps to go to dive school.  Becoming a certified diver requires taking three series of lessons. New divers must learn about the physics and safety of diving. And, they must practice diving skills first in a closed water area and then on actual beginner dives. Several organizations offer official diving certifications.

Scuba diving for fun first became possible with the development of the Aqualung by Jacques Cousteau and Emile Gagnan in the early nineteen forties. In the United States, articles in popular magazines about Cousteau and his underwater exploration methods helped bring attention to scuba diving. Because of the cost of the equipment, diving did not become a widely available sport until years later.

Taking diving classes and becoming certified are important for knowing how to dive safely. For example, you need to know how to put a regulator back in your mouth if it falls out underwater. And, you need to know how to clear your mask if it fills with water.

There are many other safety issues to consider when diving. For example, when going down deeper in the water, a diver must be careful to equalize the pressure in his or her ears. This is done by holding the nose and blowing very gently. Otherwise, the extreme pressure from the surrounding water can cause damage to the middle ear and sinuses.

Decompression sickness is a major concern for divers. The deeper a diver goes, the more pressure the surrounding water puts on the volume of the air inside his or her lungs.  And, the deeper a dive, the more nitrogen gas goes into the diver's blood.

For safety reasons, a diver must measure the length of his or her dive based on its depth so as not to exceed a safe amount of nitrogen absorption.

When divers rise to return to the water's surface, they must continue to breathe and rise no faster than the air bubbles around them. For very deep dives, they must stop and decompress at certain levels. This way, the highly pressurized air in the diver's lungs has time to leave the body before it expands. If a diver rises to the surface too quickly, he or she can become extremely ill with decompression sickness, also known as "the bends."

Another important aspect to diving is having a "buddy" system. By having a diving partner, you can watch over one another and help each other if there is an accident.

One important diving rule is to never touch any of the sea life. This rule is both to protect the diver and to protect the underwater environment.  For example, there is a reason fire coral received its name. This kind of coral causes a painful burning feeling if touched. A diver could also be cut by touching a sharp piece of coral.

Coral may seem hard like stone, but it is actually a very fragile organism. It can be damaged if divers touch or stand on it.  In order to protect the beautiful coral reef systems, divers must treat them with care.

TITO BALDWIN: "I think everyone takes a different experience away from diving.  I think what they love about diving could be the color of the ocean, could be the peacefulness, it could be a gamut of things. Everyone is different."

That was Tito Baldwin, a rescue diver from the Bahamas who has been diving for almost thirty years. He has done everything from diving to explore underwater shipwrecks to dives eighty meters deep. It might not surprise you to know Tito Baldwin's favorite place in the world to dive.

TITO BALDWIN: "Anywhere in the Bahamas, because the Bahamas is probably the most beautiful water. The further south you get away from civilization, past Georgetown down to the Plana Cays, Hogsty, Little Inagua where it's untouched by humans. It's just vibrant, alive, colorful, fish everywhere. You get some pretty good extreme diving. You've got good walls, you've got good tunnels and caverns, there's wrecks. Everything you could possibly imagine."

We went on a shark dive with Tito Baldwin in an area of the Bahamas called the Exumas.

The dive site known as Danger Reef is just south of Indigo Island. The water there was very rough. But, once you flip backwards off the boat and enter the water, you enter a calm and colorful world.

The main purpose of this dive was to see the many Caribbean reef sharks that gather in this area. These sharks have a rounded and short snout and big round eyes. They eat mainly bony fish. A fully grown female Caribbean reef shark measures about two to three meters, while a grown male measures one and a half meters or more in length.

It is very exciting and a little bit strange diving among the sharks. You feel as though you should be afraid, even though the sharks are not aggressive at all. The sharks just swim around, watching what is going on around them.

At Danger Reef, there were also many large Nassau grouper and yellow fin grouper fish. If you float above the large coral formations you can examine the smaller creatures swimming in the reef. The bright yellow and purple fish called the fairy basslet look like small swimming jewels. Many kinds of fish swim in and out of the brain coral, elkhorn coral and sea fans, which wave gently with the current.

Back on the boat, we asked Tito Baldwin more about the safety of diving with sharks.

TITO BALDWIN: "When you get in the water with sharks, people are automatically scared because they've seen 'Jaws,' they've seen all these crazy movies. But sharks are just like every other animal in the water, they are petrified of human beings. We were two feet away from five foot sharks and they were just kind of circling around us like everything else in the water. The groupers were close to us, the sharks were close to us, the yellow tail were close to us. They're kind of curious, and they are more afraid of us than we are of them."

There are many other beautiful places around the world to dive. Scuba Diving Magazine recently listed several of the "must see" diving sites. These include Bonaire, one of the Netherlands Antilles Islands off the coast of Venezuela. Here, divers can explore many reefs within a protected marine park. Divers can even explore the sea creatures that live in and around the ship, Hilma Hooker. This seventy meter long cargo ship sank over twenty years ago.

Off the coast of Baja California in Mexico, divers can see large sea creatures like sharks, giant manta rays and dolphins. Scuba Diving Magazine also recommends the Fiji Islands in the South Pacific Ocean. Many divers go here to see grey reef sharks or hammerhead sharks.

In Australia, divers can explore many interesting areas, including the Great Barrier Reef.  It is the largest coral reef system in the world. Measuring over two thousand kilometers in length, this extraordinary natural formation offers many exciting dive possibilities. Also in Australia, the Cod Hole diving area off the Ribbon Reefs is famous for its large potato codfish. And at the Lighthouse Bommie site, divers can swim with minke whales.

Scuba diving in any of these places is an extraordinary experience. This popular activity allows people to see an expansive and exciting underwater world in a new way.

This program was written and produced by Dana Demange. I'm Steve Ember. And I'm Barbara Klein. To see pictures of a dive in the Bahamas, visit our Web site, voaspecialenglish.com. Join us again next week for Explorations in VOA Special English.