Scuba

Every 10 metres, the pressure increases by one atmosphere, so, at 10 metres, total two atmospheres, it would double, to 50 litres per minute. Ten more metres, total three atmospheres, three times surface, or, 75 litres per minute Fresh and salt have the same pressure, the only two real differences are buoyancy; salt is more buoyant, and then...there's taste psi is an old measure of pressure, not volume

In the Arabian Gulf - from Bahrain, and Japan amongst other places.

Eg.

The main reasons for people to have started diving at first would have been for food, pearl diving, sponges and shells. The desire to swim underwater for various reasons must have existed for as long as Mankind has swum. Pearl diving is still practised today in some locations in much the same way as they did in the beginnings of the history of scuba in all its various forms.

Scuba tanks get hot when you fill them. Putting them underwater keeps them cool. If they overheat, the burst disk may blow. But even if it doesn't, a "hot" fill will cool down to a lower pressure, so if you think you have filled the tank to 3,000 PSI, when it cools down you will find that you only have, say, 2,750 PSI in your tank.

in one of the them you are wet and in the other one you are dry

honest... it's that simple. a wetsuit is (usually) made of neoprene and allows a limited amount of water into the suit. that is why you want a good fitting wetsuit, because you do NOT want a lot of water moving in and out of the suit, just a little. this small amount of water (debateably) warms up and helps the insulation properties of the wetsuit

a drysuit is just that. you are COMPLETELY dry for the duration of your dive. it is therefor also much more complex in construction to complete this herculean task of keeping all water out of the suit from neck seals, to arm seals and such.

ps: it is easy to weeWee in wetsuit, you need to have all kinds of special apparatus to weeWee in a drysuit.

you don't, you can dive naked if you'd like.... but you can also go snow skiing in the nude as well... it's all a matter of comfort. wetsuits help you retain heat and water removes heat 25x faster than air, so you DO get chilly faster in water... a great simple description is located here:

In the basics like masks, fins, and snorkel it has changed very little.

In breathing apparatus it has changed significantly. The largest change has been the move from two hose regulators to single hose. The adoption of Diaphragm and environmentally sealed regulators is another big technological leap.

Dive computers which compute the no decompression time for dives was another large step.. Previously, and admittedly still today, many people used precalculated tables which limited the time of the dive. For example if the deepest part of the dive was to 100 feet the tables said you could only be there 8 minutes before having decompression stops. Today with a computer doing the math on-the-fly it is possible to have a dive X minutes longer and still swim around at shallower depths.

Submersible pressure gauges are another big advancement. Earlier divers used a "k" valve which would close when most of the air was gone. You could open it again and then breathe the last of the air as you surfaced. Now a diver always knows how much air is in their tank. The Boyancy Control Device or BCD is another advancment. By wearing a vest that could be filled with air a diver could float neutrally bouyant in the water.

SCUBA stands for Self Contained Underwater Breathing Apparatus.

The B stands for breathing.

Most scuba diving photographers don't make a lot of money at it. I have been scuba diving all around the world and have been diving with lots of photographers and have a lot of friends that consider themselves to be underwater photographers. Every once in a while someone will have a photo published in a magazine but not very often. Some people put together books of their photographs and try to sell them. Most people take the photos for their own person use as there really isn't a good way to make money as a professional underwater photographer. Some people have made money going for a dive and taking photos of other divers and such but plan on eating a lot of Spam if you plan on living on the earnings of underwater photography. There are too many other people doing the same exact thing.

Recreational divers usually don't go any deeper than 60ft. The recreational dive limit is 130ft.

Loon

A submerged swim is any swim done under the surface of the water. During early dive training in a pool the students are often asked to do a submerged swim from one side to another and gradually, that same swim is from end to end (longer distance). The idea is to build lung capacity and stamina.

When you are diving the nitrogen in an air supply dissolves into the blood and tissues due to the high pressure. When you start to come up the pressure decreases and the nitrogen comes out or "undissolves" (like fizz in a bottle of pop) and forms bubbles in your blood vessels and tissues. This stops the blood from flowing and forms bubbles, which expand the vessels, causing a painful condition known as "the bends". Bends can also happen if divers fly immediately after diving. The pressure in airplanes is even less than that at sea level.

== == The first equipment used that actually allowed breathing underwater was invented in 1620 by Englishman Cornelius Drebbel. Designed for use in an oar-powered submarine, it used heated saltpeter to emit oxygen. The resulting potassium hydroxide absorbed the carbon dioxide produced during respiration. This first crude "rebreather" went generally undeveloped for two centuries.

Inventions in 1853 by Belgian T. Schwann, in 1878 by Englishman Henry Fleuss and in 1900 by Englishman Sir Robert Davis, were some of the earliest working self contained breathing gear. These systems were "closed-circuit" designs, meaning that the exhaled gas is retained in the system and made breathable again. They all shared the common trait of using pure oxygen as the breathing gas. This limited their use to very shallow water (<30 feet) due to the toxic effects of oxygen at increased partial pressures. These designs were primarily used, in fact, in rescue and mine safety applications until the 1930s when Italian sport spearfirshermen began to use them for spearfishing.

World War II saw the first military application of oxygen-based rebreather-type SCUBA equipment, first by the Italians using modified spearfishing units and then by the English using designs based on captured Italian units. The German firm Draeger, which had developed a rebreather for mine rescue in 1907, supplied oxygen rebreathers to the German military. All of these oxygen-based systems were limited to shallow water demolition and combat swimmer delivery. American Christian Lambertson developed this concept into the first truly modern military rebreathers beginning in 1939. Lambert's devices were the first to actually be called SCUBA, the wartime code name for self-contained underwater breathing apparatus.

As far as most divers are concerned, however, the real breakthrough in SCUBA came in in 1943 by Frenchmen Emile Gagnan and Jacques Yves Cousteau. Modifying a welding regulator into a pressure-sensitive demand regulator and coupling it with three air-filled welding gas cylinders, they invented the first open-circuit SCUBA gear. Open-circuit SCUBA allows the exhaled gas to escape into the water as waste gas. The two Frenchmen eventually sold this equpment under the name "Aqua-Lung" and started a company which became U.S. Divers and is now known as Aqualung International.

The Gagnan/Costeau invention of open-circuit (non-rebreathing) SCUBA using air as the breathing gas allowed the first widespread diving by civilians. The use of air allowed diving to depths far in excess of those allowed by pure oxygen and the open circuit design could be used safely with relatively little training. The Aqua-Lung was the key invention that opened up the oceans to generations of recreational divers.

The first Aqua-Lung designs used a single regulator mounted at the tank valve which delivered air and exhaust gases via two large-diameter corrugated over-the-shoulder breathing hoses very similar to those used by rebreathers. A generation of early SCUBA divers grew up watching actor Lloyd Bridges as Mike Nelson using double hose Aqua-Lung regulators on television's Sea Hunt program. The first modern two stage, single hose regulator was manufactured and distributed by Divers Supply in Wilmington California in the early 1950s. This design, an offshoot of surface supplied commercial gear, uses a first stage regulator mounted at the tank valve delivering air to mouthpiece-mounted second stage via a small-diameter intermediate-pressure (140 psi) hose. Today, virtually all modern open-circuit SCUBA gear uses this design, though Aqualung did market a "modern" double hose Mistral model in 2005 and 2006.

Nothing other than training. Technical diver do it all the time, but recreational divers are limited by either air or nitrox which is narcotic at 40 meters (131 feet) and a very short time limit where technical divers can be trained in using helium as well as how to perform decompression stops.

A float with a red flag with a diagonal white stripe is the symbol for "Divers Down"; Scuba divers are underwater in this area. Be cautious in the area of the float, because the divers will surface nearby.

Depending on how deep you dive, the maximum amount of time for the planned deepness of the next should be worked out well in advance, to account for the reduction of nitrogen levels.

There are 2 flags, either of which can be used.

The international "A" flag which is white and Blue

The red-and-white dive flag

Hell if ik..

People are dumping trash in water.

The Gulf of Mexico is a popular place for scuba diving. More and more artificial reefs are being placed, attracting more fish and coral growths.

It would cost a lot of money I'm not sure exactly how much but about £25,000.000 for a month.

Because if you try to dive to the bottom of the ocean without an oxygen cylinder, you would have to surface again before you even get all the way down. Furthermore if you did manage to get to the bottom you would have to swim back to the surface for air and if you cant get to the surface in time you could very well drown by water filling up your lungs.