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Scuba
S.C.U.B.A. = Self Contained Underwater Breathing Apparatus. Here is all the information you need to learn and be safe while enjoying this great sport. Explore the last frontier and uncharted depths in the S.C.U.B.A. category.
999 Questions
Who was the first person to deep sea dive?
The official world record is held by Nuno Gomez (South Africa) who recorded a dive to 1,076 feet in 2005.
Unofficially, most people accept that Pascal Bernabe (France) actually accomplished a slightly deeper dive (1,089 feet) later in 2005, but Bernabe's dive was not accepted by the Guiness Book of World Records for reasons that are unclear.
How long does a scuba diving certification last?
There are no exact numbers, but PADI, the largest diver training organisation publishes statistics on its certifications, and it certifies approximately 950,000 divers per year. However, only about 550,000 of those are new divers - the rest are divers who are already certified but who have received further advanced training.
It has been estimated (by the NY Times) that PADI certifies about 70% of divers trained in the US, and about 55% of the divers trained worldwide. If we extrapolate those numbers, then that suggests that every year about 1,725,000 diving certifications are issued, of which approximately 1,000,000are new divers.
But obviously the more one extrapolates statistics and estimates, the fuzzier the maths gets, so I would treat those as very rough estimates.
What is scuba diving used for?
S.C.U.B.A. is an acronym for Self Contained Underwater Breathing Apparatus.
No one should attempt to use scuba gear unless they are trained. While scuba is a safe sport, proper training is required. Check with your local clubs for instruction courses.
What is the maximum depth ever reached in a scuba dive?
Given a solid suit or vehicle, where pressure is maintained near normal sea-level (1 atmosphere), there is obviously no limit, except that we haven't yet built a machine that can with-hold that type of pressure yet. But for humans without such protection, the pressure levels in water below 1000 feet (300 m) present severe problems.
(see related links)
Modern recordsA Navy diver submerged 2,000 feet (609.6 m), setting a record using the new Atmospheric Diving System (ADS hardshell suit), off the coast of La Jolla, CA, on Aug. 1 2007.The deepest open circuit scuba dive was accomplished by Pascal Bernabé (Ralf Tech/WR1 Team) who on July 5, 2005 descended to 1,083 feet (330 m). The dive took place near Propriano, Corsica.
Re-Breather UseThe options for modern exploration are most commonly open circuit scuba and re-breather. Diving is limited by the correct mixture of breathable gases. On open circuit "classic" scuba the gas must be mixed ahead of time, while on re-breathers a diver always has the right mix of gas for the depth. Australian diver David Shaw successfully used a modified recreational re-breather to reach a depth of 888 ft (270 m) in fresh water in 2004. (Shaw died on an attempt to recover a fellow diver's body in 2005.) Oxygen RequirementsThe maximum depth that you can dive safely on air is dependent upon the partial pressure of oxygen. The air that we breathe at the surface is at a partial pressure of 0.2 bar .The partial pressure increases as your depth increases : at 10 metres it will be 0.4 bar and at 20 metres it will be at 0.6 bar. Oxygen becomes toxic at approximately 1.6 bar partial pressure, giving a maximum safe diving depth on ordinary air of around 70 metres (230 ft) . Diving to this extreme depth is not recommended, as individuals tolerances may vary. Deep-diving Gas MixturesThe maximum depth someone can dive will be directly related to the percent of oxygen in the breathing mixture. The air mixture we as humans breath is mostly made up of oxygen and nitrogen. The ratio is around 80% nitrogen and 19% oxygen and 1% other gasses. The same gas, oxygen, that keeps us alive can become toxic and kill us under high pressure. But one way to prevent oxygen toxicity is to reduce the concentration of oxygen and replace it with a different gas, such as helium. Since our bodies only use about 5% of the 19% of oxygen in air, we can replace a portion of the gas with something that is relatively safe under pressure. This is called a tri-mix gas. It can be used to dive much deeper than the recreation limit of 130 feet (40 m). Another physiological problemAs the previous answers all indicate in one way or another, the primary limiting factor in most cases at least is PPO2 (partial pressure of oxygen) and various gas results including hypothermia, which gases like helium exacerbate. However, in super-high pressures, there is a problem with denaturing of various proteins in the human system. This rare and unlikely problem is still in the books and not reality, as human descent to such depths and ambient pressures has never been tried. When the Trieste descended to 36,000 ft (10,900 m) in 1960 (Marianas Trench), the people inside were protected at one atmosphere. It's likely that with exposure to extremely high pressure, human physiology may fail, for reasons unrelated to gas problems.Proteins denaturing is detectable by increased neuropathy. Given a "perfect" gas mixture, this could eventually prove fatal. Divers Alert Network (DAN) was the source of this, with the USC Catalina Chamber circa 1970, and may have indicated problems with the medullary sheath as well.
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Obviously the limit for recreational diving as it is defined by PADI (Professional Association of Diving Instructors) is 40m. This would be achieved using ordinary nitrox (a mixture of oxygen and nitrogen; basically air but with a slightly higher percentage of oxygen). For BSAC and SSAC (British Sub Aqua Club and Scottish Sub Aqua Club) the limit is 50m, but it is generally acknowledged that beyond 40m a decompression stop on ascent is required. BSAC and SSAC both teach deco as a part of their dive training courses. The purpose of decompression is to allow bubbles of nitrogen to escape from the blood and prevent DCI (Decompression Injuries); also to increase and decrease the air volume in the lungs and sinuses at a safe rate to minimise the effects of barotrauma on the air spaces (which are otherwise liable to implode). Technical divers scuba dive at greater depths, and one of the methods they might use is an open circuit rebreather as has been discussed above; alternatively multiple cylinders and pony bottles. Oxygen toxicity occurs as a result of the increased pressure and can result in seizures (the pressure increases with depth at a rate of one atmosphere per 10 metres) and for this reason the maximum depth at which air can safely be breathed is much debated. The general consensus is that it is around the 60m mark but of course it varies from person to person and it would be unwise to venture beyond the defined limits of recreational diving without appropriate technical training.
Through diving with various complex gas mixtures individuals have managed to reach maximum depths of around 300m, but would probably have to be taken straight to an onsite hyperbaric chamber afterwards. Pressure underwater increases at a rate of an additional atmosphere per 10 metres. The effect of this upon the lungs and sinuses is that they experience a 'squeeze' - the air volume within these air spaces in fact halves with every additional atmosphere! Divers are taught to 'equalise' (add air to the air space) their sinuses to maintain the same air volume and avoid discomfort or worse when diving. They are supposed to do this as they ascend or descend and it is achieved by pinching the nose inside the mask and breathing out, thus using the air from the lungs. The effect of the increased pressure on the lungs is less noticeable because the lungs are comparatively so large and flexible, but obviously there is little that can be done to equalise them. Generally speaking the lungs are not dangerously subject to barotrauma at depths safe to dive using air, but as you can imagine, at 300 metres the pressure has increased by 30 atmospheres, meaning the air volume of the lungs has been compacted 30 times! At greater depths than this the lungs would quite simply implode, or else could explode on returning to the surface due to excessive expansion.
What happens to the buoyant force when the amount if the density is increased?
Yes. Buoyancy force = weight of liquid displaced.If an object is less dense than the liquid, it floats. In this case no liquid is displaced. If the object is more dense than th4 liquid, it will sink displacing some liquid. the displaced liquid weight is the buoyancy force.
How do firefighters and scuba divers protect themselves from extreme temperatures?
The primary purpose of a "diving suit" is thermal protection. According to a study done by the University of Michigan, the average temperature of water near the ocean surface is about 17°C (62.6°F). This, coupled with the fact that water is a very good thermal conductor (it conducts heat away from your body about 22 times more efficiently than air) makes hypothermia one of the most significant risks to a scuba diver. The primary purpose of a diving suit is to prevent this.
There are two general categories of diving suit in common use: the wet suit and the dry suit. The goal of both is the same. They're designed to keep you warm. A wet suit, usually made of neoprene, sometimes sandwiched between two layers of fabric, is open to the surrounding water. It operates by trapping a very thin layer of water between the diver's body and the thermally insulating neoprene. The diver's body quickly heats this thin layer of water, which then serves as a further thermal insulator.
Dry suits are exactly that: dry. Made of a variety of waterproof materials including crushed neoprene and rubber treated fabric, dry suits are fitted with water-tight cuffs and neck seals. Divers typically wear insulating underwear under dry suits. The underwear and the air trapped in the suit insulate the diver from the cold water.
In both cases, diving suits increase a diver's buoyancy by displacing water with either the neoprene suit itself or by the air trapped inside the suit. This is problematic in that it requires supplementary weight to compensate for the buoyancy to make the diver neutrally buoyant. Without supplementary weight, a diving suit wearing diver would not be able to descend in water.
A secondary benefit of both wet and dry diving suits is physical protection of the diver's skin against abrasion and attack by sea life such as jellyfish and coral. Divers diving in warm water often use thin lycra or spandex suits called dive skins. Dive skins provide minimal thermal protection but do provide a measure of physical protection.
Can a tooth implant break at depth while scuba diving?
It's unlikely that fillings would ever crush, but theoretically an extremely badly made filling could crush from the pressure of a deep descent. A more common dental issue associated with diving is empty pockets of air in a filling expanding as you ascend and causing pain.
It's worth mentioning that you're a scuba diver to your dentist, and check out DAN(.org?) (Divers Alert Network) for dental health related issues.
AnswerNo, fillings do not crush, and no, they do not trap air. This is an urban myth. There has never been even one authenticated case of either ever recorded. If you think its your teeth, its most likely your ears, believe it or not, its really hard to tell the difference.
Answer Improvement.
Far more frequent than problems with dental work are sinus problems. One old, hoary way of testing if your toothache is really a sinus problem is to hop on the heel of one foot on the side that hurts. If it throbs every hop, it's sinus and not dentistry.
I realize this sounds like voodoo. The science of it is that a swollen sinus cavity will press down on the same nerve plexus that hurts when an upper tooth gets problematic. However, that bouncing motion will really throb with a swollen sinus but won't do a thing to a tooth ache.
Doubt me? Try it :}
Another answer
I don't think a filling can be crushed, but if it is fitted badly and there is a pocket of air underneath the filling there is a possibility that as you ascend the air will expand causing the filling to pop out, however I think this rarely happens. Someone mentioned telling your dentist that you are a diver, but unless they are a diver themselves they will have no idea why you are telling them that so you will probably jut get an answer along the lines of'oh really? ? That'snice'
2 what happens if a diver comes to the surface too quickly?
it depends on the depth you are assenting from and the speed.
However if your were on 30m deep and assented too fast without equalizing and continuance breathing you can hurt your lung and ears
What happens to water pressure as a diver descend?
Water presure doubles every 33 feet. Water presure doesn't actually double every 33 feet. It actually increases in pressure by one atmosphere every 33ft. Thus at 33ft the pressure would be twice what it is at the surface. At 66ft however the the pressure would be three times that at the surface... 99ft, 4 times and so on.
Is compressed air in a scuba tank homogeneous?
When you put a gas into a cylinder the particles move all over the place by a process called diffusion. Even though they have a different molecular weight, the heavier molecules do not settle at the bottom of the tank. You could take a sample of air from anywhere in the tank and it would be similar. This means it is homogeneous.
How old do you have to be to get a scuba diving license?
Kids as young as 10 years old can enroll in Junior Open Water courses and those 15 years and older can enroll in an Open Water course. When offered, Junior Open Water (diving with adult supervision only) certified divers are automatically upgraded to Open Water divers on their 15th birthday with no need for re certification. This can vary depending on the certification agency involved.
You'll also need to be in good health with no major health problems.
How do divers handle The Bends?
Because it can seriously injure or even kill you.
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Because a rapid ascent from the pressure of the deep can cause nitrogen bubbles to form inside your body. It is like taking the pressure off of a can of soda and watching the gas fizz all over. Now imagine a similar even taking place in your blood and the fluid in your tissues! This causes pain in the joints, and can even block the flow of blood in your body. Chaz
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How much saturation diving course?
To become a saturation diver you must first qualify and work as an air diver. Once you have a set amount of logged dive hours, working in surface supplied equipment in open water, you can complete a training course to gain your saturation (also known as mixed gas or closed bell) diving certification. The Underwater Centre in Tasmania provides ADAS diving certifications in both air and saturation diving, and The Underwater Centre in Fort William provides HSE diving certifications in both air and saturation diving. Both ADAS and HSE certificatoins are internationally recognised, allowing you to work anywhere in the world.
Why is decompression sickness also called The Bends?
Decompression sickness the bends is a painful and potentially fatal malady an environment of high pressure to one of lower pressure.
You may also want to see the answer in the question "What does decompression mean in diving?"
It is a device that looks like a bell and helps you dive into very deep places. the bell hosts the people in it sheilding them from the pressure.
I personally like the wetsuits form Patagonia. I also like the way their products are made and the way Patagonia thinks. Google them and you will be able to view their selection of apparel, and sports wear and gear.
What is the acronoym for scuba?
Self Contained Underwater Breathing Apparatus
Scuba is an acronym which stands for, Self Contained Underwater Breathing Apparatus.
Scuba stands for Self-Contained Underwater Breathing Apparatus.
Self Contained Underwater Breathing Apparatus
Not sure who originally "coined" it, but it means "Self-contained underwater breathing apparatus"
Jean-Jacques Cousteau, the French explorer/ environmentalist was the inventor of the SCUBA. In fact, he coined the term.
Self-Contained Underwater Breathing Apparatus.
How does a scuba diver control their depth?
WARNING: A BIT OF MATH FOLLOWS
A diver's buoyancy is determined by the mass of the water they (and their attached equipment) displace. Water density varies with temperature and salinity, but a good rule of thumb is that 1 cubic meter of water "weighs" about 1029 kilograms. That pencils out to about 64 pounds per cubic foot.
A typical diver displaces about 2.5 to 3 cubic feet of water. That's equivalent to about 160 to 192 pounds of sea water. Let's assume the diver displaces 2.5 cuft of water. That means that the water they displace will "support" 160 pounds. If the diver weights less than 160 pounds, she'll be positively buoyant and will float. If she weights more, she'll be negatively buoyant ad will sink. The ideal circumstance that a diver strives for is to be neutrally buoyant, so no energy is expended to keep from sinking or floating.
If our diver and her gear weigh 160 pounds, she'll be neutrally buoyant. In practice, our diver will carry enough weight to make her approximately neutrally buoyant. If she inhales air from her scuba cylinder, her chest cavity will expand, displacing a higher equivalent weight of water, and she'll ascend. If she exhales, she'll displace less water, and will descend.
This ideal neutrally buoyant state allows a diver to ascend and descend with minimal effort. In practice, however, things are constantly changing during a dive. Wetsuits compress with depth, meaning the deeper our diver goes, the less water she'll displace. So as she descends, she'll have a tendency to descend more quickly.
Her scuba cylinder displaces a constant amount of water, but the more air is used, the less it will weigh. This means that our diver will have a tendency to become more positively buoyant... she'll "float" more... as the dive progresses.
In order to adjust for all of these variables, divers wear a "Buoyancy Compensation Device" (BCD). This is generally a vest shaped bladder that can be inflated using air from the scuba cylinder. It is fitted with a dump valve that allows fine tuning of the amount of inflation, and thus the amount of water it displaces.
During a dive, our diver will adjust the amount of air in her BCD to maintain neutral buoyancy. Then she'll use her breathing to make fine adjustments in her vertical position.
Divers diving in colder environments will often use a dry suit in place of the wet suit worn by most recreational divers. This dry suit is filled with variable amounts of air from the scuba cylinder, much the same way a BCD is. A dry suit can be used alone, or together with a BCD, to control buoyancy.
In all cases, a diver will use a depth gauge, or a dive computer which measures depth, to monitor their depth throughout a dive.
The History of Scuba diving goes back through the centuries
People have been diving underwater throughout the ages, probably for as long as people have been swimming….. It may not have been Scuba but it is the beginnings of the quest throughout the history of scuba diving to be able to dive underwater and be able to breath underwater.
There are records, in some cases little more than myth, of the methods used and what was done while diving.
Read more at this site:
What would happen to a diver who does not exhale while surfacing from a 30 m dive?
At depth you end up with compressed air in your lungs. If you hold your breath as you surface the gas expands and can tear the delicate structure of the lung. This can happen at much less depth than 30M. 100ft, which is a similar depth, is the depth used by the Royal Navy at HMS Dolphin in Portsmouth, England, to train submariners to escape from submarines. They are taught to exhale in a constant stream from the bottom of a tall tank to the surface. This is because it is quite unnatural when you are underwater to breathe all your air out and you want to hold your breath.
If you use scuba equipment and surface slowly breathing normally, you should not have any ill effects and it would only be under some kind of extreme emergency such as escaping from a submarine or losing all you air whilst solo diving that you would ever surface in that way. Naturally you should not dive on your own for that reason.
Where does the word scuba diving come from?
1839 Canadian inventors James Eliot and Alexander McAvity of Saint John, New Brunswick patent an "oxygen reservoir for divers", a device carried on the diver's back containing "a quantity of condensed oxygen gas or common atmospheric air proportionate to the depth of water and adequate to the time he is intended to remain below".[4] But was that SCUBA (Self Contained Underwater Breathing Apparatus) or ORFD? sounds like SCUBA, but... there is another entry:
1876: An English merchant seaman, Henry Fleuss, develops the first workable self-contained diving rig that uses compressed oxygen. This prototype of closed-circuit scuba uses rope soaked in caustic potash to absorb carbon dioxide so the exhaled gas can be re-breathed. but most people generally agree that MODERN SCUBA was invented by a couple of guys in France: 1943: Jacques Cousteau and Emile Gagnan invent and make an open-circuit diving breathing set, using a demand regulator which Gagnan modified from a demand regulator used to let a petrol-driven car run on a big bag of coal-gas carried on its roof during wartime shortages of petrol. Cousteau had his first dives with it. He made two more aqualungs: there were now 3, one each for Cousteau and his first two diving companions Frédéric Dumas and Taillez. His aqualung remained a secret until the south of France was liberated. This type of breathing set was later named the "Aqua-Lung". This word is correctly a tradename that goes with the Cousteau-Gagnan patent, but in Britain it has been commonly used as a generic and spelt "aqualung" since at least the 1950s, including in the BSAC's publications and training manuals, and describing scuba diving as "aqualunging".
How is buoyancy used by scuba divers?
SCUBA divers control their buoyancy to keep off the sea floor or from floating up to the surface, to avoid obstacles both above and below them, and to have a more relaxing dive with minimal physical effort. As a diver changes depth, they need to either add or release air from their buoyancy compensator (BC or BCD) to maintain neutral buoyancy. A diver in control of their buoyancy can move through the water with minimal fin input and breath control making the dive a lot more enjoyable (not to mention longer due to not using a lot of air inefficiently to maintain buoyancy control).
Buoyancy is not really used by scuba divers, but it does act against them. Since the human body and the gear during scuba diving is held up by the water, especially at farther down depths of the ocean, where the water is more dense because of the weight of the water and the air holding it down. Because of the buoyancy, the divers have to wear weights to offset this buoyancy. Since in scuba diving you use wetsuits, and since these suits have nitrogen bubbles to assist insulation, this makes you float even more. And since your cells contain lipids and other materiels that are lighter than the water, this makes you float even more. This means that scuba divers must use weights to offset the buoyancy.
How many scuba divers are attacked by sharks each year?
Virtually zero. The reason I say virtually is that: * The actual number of divers being attacked by shark much less getting killed is so low as to be statistically insignificant and... * Of the few that do, some don't practive even the most basic safety (consider Valerie Taylor, who made a chain-mail suit, created a feeding frenzy, and jumped into the middle to see if the suit prevented shark attack (and it did -- she wasn't killed -- only a slight nick). Basic rules of safety are: * Don't look like a fish in trouble. That's what shark eat. Don't look like food. Don't flop around -- swim purposefully and smoothly. * Don't smell like a fish in trouble. While shark probably don't react much at all to the scent of human blood, they do detect fish blood very well -- that's their prey. Clean off fish blood and don't tow bleeding strings of fish in dangerous waters. * If you are approached aggressively by a shark, back away smoothly. Shark are territorial in some cases. Get out of range. How will you know if the shark is being aggressive? You'll KNOW. If you aren't sure, act respectfully, keep a distance, and don't act like sharkbait. [[User:Cjonb|Cjonb]] 23:49, 2 Jun 2008 (UTC)
