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Helium is actually only rarely used in Scuba tanks, and then only when blended with other gases (most commonl oxygen and nitrogen to make trimix). However, the main purpose of adding helium is to reduce the narcotic effects of other gases when you descend to greater depths.
Breathing normal air, divers begin to experience nitrogen narcosis (or the "rapture of the deep") at about 100 feet. Beyond about 130 feet it starts to become debilitating. Beyond about 170 feet, divers can be rendered completely insensible. But with helium mixes, divers have been able to dive safely as deep at 300 - 400 feet.
It is often mixed with other gasses to create a mixture that will extend divers endurance, in extreme diving & deep diving mainly though.
*At extreme depths the pressure is high enough that if you had nitrogen in the tank it would become saturated enough in your blood that you would develop nitrogen narcosis. Helium wont be absorbed across the alveoli and will not react with your body so it is used for extreme depth's.
Improvement
It has nothing to do with endurance. Also, helium is absorbed in the blood in the aveoli and is absorbed by the bodies tissues. Helium is used for deep diver (diving deeper than 100 to 130 feet in the US) since helium is not as narcotic as nitrogen and a diver will have a clearer mind.
Because when Scuba Divers go deep, the normal air goes poisonous.
Improved Answer
Helium is used since it has very low (almost non-existent) narcotic properties. The nitrogen in air is highly narcotic at depth and adding helium allows one to dive without the effects of narcosis (where one's mind is impaired).
Helium has many benefits as well as disadvantages. This answer could get very involved, but keeping it simple, the nitrogen in normal air is narcotic which affects the divers ability to properly think and function on deeper dives. Helium is far less narcotic, so it is added to the air on deeper dives so the diver can function and think clearly since the narcotic effect is overall removed. Helium used to just be used on decompression dives, but now it is being used for recreational dives too in combination with air and oxygen for a mix called tri-mix since it contains the 3 gases of oxygen, helium and nitrogen. Recreational divers are now getting the benefit of a less narcotic gas by adding helium to their scuba cylinder to do 100 foot dives.
One benefit of helium is it is less soluble than nitrogen which is a positive benefit for the body when breathing a gas. However it also enters the divers tissues faster than nitrogen - which is a drawback since a diver will build up more gas in the body faster. But it also leaves the body faster than nitrogen - which is a benefit for technical divers that must do decompression stops. This rapid off-gassing effect can be further increased when a diver switches from a dive gas containing helium to a different gas at a decompression stop that does not contain helium. By switching to a gas during decompression that does not contain helium, then the helium in the body encounters no resistance in leaving the body which allows it to off-gas even faster. But helium has another drawback ... it has bad thermal property and will cause you to lose body heat faster as you are exhaling your body heat. If diving in colder water, this needs to be accounted for so you have plenty of underwater insulation.
So to sum up, helium is less soluble (a benefit during any dive) and will leave the body faster during decompression, but it also has the drawback of entering your body faster and being another expense that must be paid for. Therefore divers will use helium on some dives and not on others depending on the type of dive being made.
Helium is a very low narcotic gas. By adding helium, there is less nitrogen percent in the cylinder and therefore the gas being breathed is less narcotic. This allows divers to dive deeper with very little narcosis.
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What are the gases that scuba divier breathe?
In recreational diving, most divers use compressed air (as in the normal air we breather at the surface). Some divers are also trained to use special gas mixes called Nitrox which have a higher oxygen content and lower Nitrogen. Professional (or commerical) divers tend to use more advance mixes such as Heliox or Trimix which combine Oxygen, Nitrogen and Helium.
Who uses a scuba-suit?
Many people use a SCUBA suit for diving. Sport divers, police divers and some Navy recovery divers.
What Type of gas scuba divers use?
Diving gases which are used (in order of frequency in everyday use):Most scuba dives use conventional air as a gas mixture.However, some divers use nitrox, which is oxygen enriched air. The increased oxygen content (well, actually it is the reduced nitrogen content) allows divers to stay underwater for longer without decompression stops.Some advanced technical divers who go deeper use a mix of oxygen, nitrogen and helium called trimix. The helium in the mix reduces the effects of nitrogen narcosis, and the oxygen content is usually reduced to lower the risk of oxygen toxicity at great depths.If the dive is so deep that nitrogen cannot be present at all, the diver may simply use a helium-oxygen mix, usually called heliox.For very-very-very deep diving (usually very deep commercial or military operations), the diver can use a blend of hydrogen, helium and oxygen called hydreliox. The hydrogen is used to reduce the effect of high pressure nervous syndrome (HPNS) caused by breathing helium at great pressures.Also extremely rare, and used on occasionally in commercial diving is a mix of neon and oxygen called neox. Neox has the same benefits as heliox, but helium can affect the voice and so if divers need to communicate vocally underwater they may elect to use neox.There are two other "varieties" of trimix which have been given their own names over the years. Heliair is used to refer to any mix of helium and ordinary air. It is quicker and cheaper to blend than customised trimix, and so is often called "poor man's trimix". More common in the 70s and 80s, it is rarely used today. Conversely, some divers used trimix with hyperoxic contents (ie. more than 21% oxygen). This can be used in the narrow corridor of water between about 100 and 160 feet to offset nitrogen narcosis and also to marginally reduce decompression limits. Such mixes are referred to either as TriOx or as Helitrox, but are not in common usage.
Is there a risk when you inhale helium?
Helium is an inert gas, so it has no effect on the body. Divers use it mixed with oxygen when they dive deeply. The only real danger is breathing in so much that you don't get enough oxygen.
The gas element used in deep-sea diving?
Deep-sea diving act of descending into deep water, with some breathing apparatus, help them to remain there for an extended period. There can be multiple gases used depending on desired depth and length of dive the common is a tri-mixed gas of Nitrogen, Oxygen, and Helium.
Why scuba divers use mixture of nitrogen and oxygen?
Scuba divers use a mixture of nitrogen and oxygen in their tanks because it reduces the risk of decompression sickness. This mixture, known as nitrox, has a higher oxygen content than normal air, allowing divers to stay at depth for longer periods of time. Nitrox also helps to reduce the amount of nitrogen absorbed by the body, which can help prevent nitrogen toxicity.
What is the name of the suit that divers use to survive high pressure?
The suit that divers use to survive high pressure is called a diving suit or a pressure suit. These suits are designed to protect divers from the effects of high pressure underwater, such as decompression sickness.
How do the elderly use helium?
Elderly individuals may use helium for medical purposes, such as in helium-oxygen therapy to help with respiratory issues like chronic obstructive pulmonary disease. Some may also use helium-filled balloons for special occasions or decorations. However, it is important for elderly individuals to use helium safely, as inhaling too much can be harmful and even fatal.
A person who dives?
People who dive are usually just referred to as divers. You can break them up into roughly four categories:Skin divers - who hold their breath, and do not use scuba equipment. Also sometimes called free divers.Sport divers - who dive for fun (they used to be called 'recreational divers', but now this term is used to distinguish sport divers from 'technical divers' who also dive for fun, but dive outside of WRSTC 'recreational' limits).Commercial divers - who dive for their jobs. By convention, this excludes recreational diving instructors, to differentiate from commercial divers who use equipment underwater, engage in saturation diving and use of elaborate gas mixes.Military divers - who form a sub-set of the navy.Not all divers fit neatly into these categories (police divers, rescue divers, fisherman who dive for their catch), but those tend to be the broad categories used.
What does helium smell of?
No. Helium is one of the "inert" gasses, also called "noble gasses", because they undergo virtually no chemical reactions at all.Helium is odorless, tasteless, and based in its atomic number of 2 and atomic weight of 4, practically massless. Helium is very light, does not support combustion and does not support life. Helium is not poisonous, but if you are "huffing" from a helium balloon, you aren't getting any oxygen - and oxygen is one of the things that you need for life.Warning! Taking one or two breaths from a helium balloon is harmless, because there is plenty of oxygen still left in your system. But there is no oxygen in a helium balloon.Because it is completely inert, it does not bind at all with the body. So deep-sea divers use a mixture of helium and oxygen for their breathing tanks, because nitrogen in pressure causes "nitrogen narcosis" - the so-called "Rapture of the Deeps" - and oxygen is flat-out poisonous at high pressures. So divers use a mixture of 95% helium and 5% (or less!) oxygen for long-duration, high-pressure diving.
What are the differences between trimix and air?
"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.
What contribution did eads and roebling's make to bridge construction?
Use of and invention of deep water caisons for divers, the diving bell
