Scuba

The buoyant force is a contact force, exerted by contact with a liquid that displaces the liquid within a gravity field. No contact, no force.

when your changing you might want to know...

like 11,000 meters

The vest is simply called a scuba vest. It's to hold your air tank and regulators :)

"Deep" diving is diving farther than 120'. Though there are no educational qualifications per se, there are a number of certifications needed to do it safely.

Certifications differ from agency to agency, but usually include:

-Scuba diver

-Advanced scuba diver, with deep dive training

-Mixed gas diving

-Multi-stage decompression diving

-Diver rescue

Specialized equipment includes:

-Dry suit

-Breathing gas mixtures such as trimix, heliox, etc (some use pure oxygen for decompression

-Dive and decompression computers

-Powerful underwater flashlights

-More stuff I can't remember.

Most scuba tanks are filled with compressed air (same as the "normal" air we breath) 21% Oxygen and 79% Nitrogen. The tanks are a variety of colors and the color does not signify anything. Special NITROX tanks have a bold Yellow and Green band which goes around the tank and is usually 8" wide. NITROX can have a range of between 32% and 50% oxygen (the balance is nitrogen). This yellow/green band - with the word NITROX can be placed on any color tank. Special tanks with exotic gas mixes will be indicated with special bands - there is no standard colors for exotic mixes.

His many underwater films turned our television screens into a portal to the seas. A couple of them won Academy Awards. He co-developed the Aqualung.

See the links below for more informaiton:

This is a difficult one to answer. In general, the term DIR as it relates to diving refers to specific procedures that were developed by a certain group of divers. Some of these divers forcefully believe their procedures are the only way to do things. Many pf the followers then take the same approach and forcefully advocate against any other procedures, so those with differing points of view can be put down. But then others that disagree with "DIR" sometimes also take a hard line against it. So in general it is the same as many other sports or activities where some believe it should be done one way and others believe it should be done another way.

the pressure in the water increases, this is why you equalize, just like going up in an aeroplane!

Barotrauma is the damage to body tissue caused by a difference in pressure between an air space in or near the body and the surrounding air.

Almost every resort in the Maldives caters to scuba divers. International certificates of all types are accepted. Most dive schools are well equipped, with regulators, BCDs, computers, masks, snorkels and fins are all available for rental. For those learning to dive, resorts offer a variety of dive courses and they are conducted in several languages, with courses conducted in English, German, Italian, French and Japanese. For those learning to dive, all resorts conduct open water and advanced courses such as night diving, rescue diving, underwater photography.

sharks generally do not care that much for human blood.. now put a few drops of fish blood in the water and that is a different story...

For what it's worth..."There is no evidence of increased shark interest in a menstruating female. The hemolytic blood associated with menses may instead act as a shark deterrent (Edmonds, et al., 1992, p. 65)."

I found the following reference particularly helpful. It is on the Divers' Alert Network and is titled, "Diving Medicine FAQs, Menstruation During Diving Activities"

http://www.diversalertnetwork.org/medical/faq/faq.asp?faqid=109

The cost to scuba dive in the state of Hawaii varies depending on the venue. The average cost varies between $100 and $150 per day, as of August 2014.

"Trimix" is a term used in commercial and technical scuba diving to refer to a breathing gas composed primarily of three gases: helium, nitrogen and oxygen. To understand why divers use this mixture of gases as a breathing gas, we'll need to take a look at the typical gas used in scuba: air.

Air is comprised of nominally 21% oxygen and 79% nitrogen. All other gases contained in air comprise well under one percent of the total mix. Nitrogen has some negative side effects when breathed at the pressures required for diving. In order to reduce the effects of nitrogen in the breathing gas, some percentage of helium is often used in place of nitrogen.

Helium is considered an "inert" gas, in that it isn't used in the metabolic breathing cycle. Since it is a small molecule gas (it has 28% of the molecular weight of nitrogen), a diver's body tissues absorb and release helium much more quickly than they do nitrogen. This reduces the risk of decompression illness when compared to a nitrogen-rich gas like air. Helium also has the advantage of not being narcotic. Nitrogen, at the elevated pressures at depth, can cause intoxication: symptom called nitrogen narcosis.

The net result of these two factors is that divers using helium in place of nitrogen can dive to deeper depths for longer periods. Deep commercial "saturation" dives and deep "technical" dives are often performed using a mix of helium and oxygen called heliox.

There are also disadvantages to using helium. The most significant of these is its scarcity and resulting high cost. World supplies of helium are critically low and the cost continues to rise. As a result, helium is most often used by divers using rebreathers and in surface supplied and deep saturation diving, all of which conserve breathing gas.

Helium also conducts heat six times more efficiently than air. This introduces the risk of hypothermia if a diver uses their heliox breathing gas to inflate their dry suit. Commercial and technical divers using heliox as a breathing gas often carry a separate cylinder of argon to keep their dry suit inflated at depth.

Trimix, consisting of oxygen, helium and nitrogen is often used in place of pure heliox. This achieves some of the advantages of heliox at a greatly reduced cost. A typical trimix mixture used in deeper diving is trimix 10/70. This consists of 10% oxygen, 70% helium and 20% nitrogen. This gas mix won't support consciousness at the surface (10% oxygen is considered hypoxic), but it does allow diving to 100 meters. Most trimix gas mixes are bespoke, with the mix percentages being designed for a particular dive profile.

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. These rebreaters all shared the common trait of using pure oxygen as the breathing gas. This limited their use to very shallow water (<30 feet [10M]) due to the toxic effects of oxygen at the increased partial pressures of greater depths. 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 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 [9.6 BAR]) 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.

I would call it the Great White Pucker Factor.

SCUBA stands for self contained underwater breathing apparatus.

This is mainly do to the pressure that the water above the diver is putting on the diver. On the surface air is putting pressure on you but it has less weight than water and as you dive deeper the pressure increases because the amount of water above you also increases.

Ancient swimmers used cut hollow reeds to breathe air, the first rudimentary snorkel used to enhance our abilities underwater. Around 1300, Persian divers were making rudimentary eye goggles from the thinly sliced and polished shells of tortoises. By the 16th century, wooden barrels were used as primitive diving bells, and for the first time divers could travel underwater with more than one breath of air, but not much more than one.In 1942, redesigned a car regulator and invented a demand regulator that would automatically fresh air when a diver breathed. A year later in 1943, Cousteau and Gagnan began selling the Aqua-Lung. Depending on how specific you want to be on methods of using contained air underwater for diving.

No one knows exactly how much pressure the human body can withstand, but it is deeper than 1,500 feet.

Scuba Diving lessons can be a lot of fun! The key decision is finding a reputable dive shop to take your lessons with. The first certification that most people choose to do is an Open Water Certification, once complete you will be able to dive anywhere in the world. PADI is the most reputable SCUBA certification agency in the world, with over a million certifications a year.

After choosing your reputable dive shop, you want to make sure you work with a good dive instructor. This key decision can make or break your entire experience. Ask to meet some of the dive instructors, discuss with them any goals or fears you might have.

The first portion of your lessons will be online or in a classroom, where you will learn all about sorts of things about scuba diving. Your first water experience will be in a pool, where you can stand up at anytime. This is to help you get familiar with what it's like to breathe underwater, if at any point you are uncomfortable, you can just stand up. In your open water pool session you learn many valuable skills. Some of those skills are, how to set up you gear, how to clear your mask and how to surface.

Normally you have to do at least three confined pool session before you can go out in to open water in the ocean or a lake.

The first open water experience is a ton fun, allowing you to get comfortable with an open water environment. Here you will have really good chance to play around with your buoyancy underwater.

In your open water sessions you will have to perform the skills you learned in your confined pool sessions. You must pass your skills tests in an open water environment to pass this portion of the class. Once you have successfully completed your multiple-choice test and open water skills test, you earn your open water certification.

Overall, the experience is worthwhile and very fun. You open up the window to explore the the amazing underwater world. For many scuba diving is not a hobby, it's a passion.

There are two types of "Diver Down" flags: the well known US version and an international version.

The US version is a rectangular red flag with a single, wide white stripe running diagonally from the top left corner to bottom right corner.

The international "Diver Down" flag is blue and white. It has a vertical white strip with two blue swallow tails. This flag is International Flag Code A (pronounced phonetically as 'alfa' or 'alpha'.) When flown as part of a message, this flag represents the character "A". When this flag is flown independently, it takes on the meaning of the "Diver Down" flag.

Both flags are intended to send the following message to other vessels: "I have a diver down. Keep well clear at slow speed." Check the links for images and specifications.

Let's start with understanding the question. Partial pressure is defined as the fractional percentage of the gas in the overall gas mixture times the total pressure in Atmospheres. If we assume we're scuba diving using air as our breathing gas, then the fractional percentage of nitrogen is 79% (or .79). Oxygen make up the majority of the balance at 21% (.21) Air is made up primarily of these two gasses. All other gasses that comprise air are considered "trace" gasses. Carbon dioxide is one of these trace gases, and accounts for about 0.039% percent of air by volume.

If we assume for a moment that we're at sea level, then the total pressure, by definition, is 1 Atmosphere (atm). This means that the partial pressure of nitrogen in air at sea level is .79. Oxygen is .21. Carbon dioxide is .00039.

Every 33 feet a diver descends in sea water adds one additional Atmosphere to the Total Pressure. This means that Total Pressure at 33 feet is 2atm and at 66 feet is 3atm. PPO2 (partial pressure of oxygen) at 33 feet is .42. PPN (nitrogen) is 1.58. PPCO2 (carbon dioxide) is .00078. At 66 feet of sea water PPCO2 is .00117 (.00039 X 3atm).