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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

How many meters below sea level is 1 ATM?

1 ATM is actually equal to mean sea level itself. Now if you filled a balloon with air and put it under the water, you would notice that the volume will decrease. This decrement will increase as you go further down. Since the volume is decreasing, pressure must be building up inside (PV=nRT), assuming that the temperature doesn't change. Thus undersea pressure will be higher than 1 ATM.

Addition

For water pressure alone, 10 meters of water is equivalent to 1 atmosphere of air pressure.

How is the quality of a pearl diver is judged?

they can change the pressure on their body to help them from drowning

What problems are there for people making deep sea dives?

Normally there is a risk of the bends (hydrogen bubbles building up in the blood stream)

Correction:

The above is incorrect. Decompression sickness (or the bends) is caused by gas bubbles comprised mostly of nitrogen (not hydrogen).

What does spg stand for in reference to scuba diving?

In reference to scuba diving, "SPG" stands for "Submersible Pressure Guage", which tells you how much air is in your tank so you can resurface before going too low on oxygen.

Why do objects placed in fluids experience a buoyant force?

All fluids exert pressure on the surface of any object in that fluid, but the pressure is not uniform over the surface of the object. Parts of the object that are deeper in the fluid will have more pressure from the fluid pressing against them than parts that are shallower. The amount of the object's surface that is being pressed down by fluid above it will be equal to the amount of surface being pressed up, but the pressure per unit area pressing up will be greater, on average, than the pressure that is pressing down.

A 1 square inch column of salt water 1 foot tall weighs just under 0.45 pounds, so it exerts a pressure of (about) 0.45 PSI. That pressure will be in addition to the pressure of any fluid that is pressing down on the top of the water column, such as the atmosphere. Thus the pressure on the surface of the ocean is about 14.7 PSI and the pressure at a depth of 1 foot is about 14.7 + 0.45, or 15.15 PSI.

If a cubic object 1 foot on each side was placed in the water with its top right at the surface the top of the cube would have 14.7 PSI * 144 square inches, or 2116.8 pounds of pressure pushing down on it. The bottom would have 15.15 PSI * 144 square inches, or 2181.6 pounds of pressure pushing up on it. The pressure on each side would equal the pressure on the opposite side, so there would be no net pressure pushing sideways. The difference in pressure pushing up and pressure pushing down would be 64.8 pounds, so there would be a buoyant force of 64.8 pounds pressing the object upward. Since the actual weight of the water column is a little bit less than 0.45 that actual buoyant force would be 64 pounds, which is the weight of 1 cubic foot of water. Thus the object is buoyed up by a force equal to the weight of the fluid it displaces.

How do the Filipino Clam Divers stay underwater for so long without tanks?

I have seen this in tv. Some divers were underwater for about 3 minutes. I think it takes a life to achieve that.

How do you get rid of dirt diver?

To get rid of dirt daubers, start by removing any existing nests you find, as these insects typically build their homes in sheltered areas. Seal any entry points around your home to prevent them from returning. Additionally, keeping your yard tidy and free of debris can reduce their attraction to your property. If the problem persists, consider using insecticides specifically designed for wasps or consulting a pest control professional.

Who holds the record for the deepest dive in the ocean?

The deepest ever dive on scuba (excluding military) was 1,083 feet (330 m) by Pascal Bernabé of France.

The official Guinness world record is 1,044 feet (318 m) by Nuno Gomez of South Africa.

It is not clear why the Guinness book of world records did not recognise Bernabé's dive.

What pressure will a scuba cylinder with a rated working pressure of 3000 psig be exposed to during a hydrostatic test?

The test pressure is always stamped on the cylinder along with the working pressure, physical volume, manufacture date etc. It is generally about twice the working pressure of the cylinder.

Is there a certain depth where oxygen becomes toxic?

The answer to this question depends on the oxygen concentration that you are using and, to a degree, your body chemistry. Hal Watts has reportedly made many "bounce" dives on "air" (21% oxygen 79% nitrogen) in excess of 400 feet in sea water. Discounting the narcotic effect of nitrogen, ambient O2 or "air" becomes toxic at around 240 feet in salt water. You should never dive without proper training, and even properly trained SCUBA divers would not dive beyond recreational limits (130 ft) without special training. Oxygen concentrations higher than 21%, or enriched air (Nitrox) will have MOD Maximum Operating Depths based upon the specific concentration of oxygen. 100% oxygen is dangerous below 20 feet and, unless you are trained in the use of military rebreathers, you should not be diving 100% oxygen. Technical divers frequently use concentrations of oxygen up to 100% for decompression in stage tanks, but they are not diving on oxygen. Many will undoubtedly realize that I am not distinguishing between 1.6 ATA and 2.0 ATA... Nor have I discussed the 24 hour clock and the cumulative effect of oxygen exposure. If you are still wanting to know the depth at which a specific concentration of oxygen or an exposure to oxygen over time can become toxic, you should take a class in Nitrox or enriched air from a internationally recognized SCUBA agency. Many questions will be answered and you will learn the formulas to determine oxygen toxicity for a given concentration. I hope this helps

How does repetition enhance the meaning and beauty of the message?

Repetition can serve to really make the receiver of a message analyze the words more closely. Also, repetition can offer different perspectives on the same message, attaching contrasting meanings and showing a new message altogether.

Can a body get sucked up into a deep sea diving helmet?

Yes it can! The extremely high external pressure caused by all the water around a diver plus the low pressure inside the helmet of old diving gear can cause such disaster.

There's actually an episode of mythbusters when this is explicitly tested.

What are different parts of breathing apparatus?

Different parts of breathing apparatus are:

face mask,Cylinder, back plate, main valve of the cylinder, harness of back plate, spider straps of face mask,neck strap,waist belt, speech transmittor, exhale valve, inhale valve,lung demand valve, first stage reducer, second stage reducer, inner face mask, o ring,

What is scuba tank VIP?

It stand for "Visual Inspection Programme", and it means a dive professional taking the valve off the tank and inspecting inside to check for cracks or contamination. It is different from the hydrostatic testing that tanks are required to undergo every 5 years, in that the inspection is purely visual.

In the US and Canada this is normally done every year.

In Europe it is normally done every two and a half years.

A scuba diver descended 51 feet from the water's surface. what would be an integer of this?

51 feet is an integer, an integer is simply a whole number (no decimal place).

Not too sure what relevance it has to diving either? My best guess at what you are after is what depth should you use on the RDP?

If so you use the next biggest number, in this case 60ft

What grade breathing air is used in SCUBA cylinders?


* The CGA Grade "E" quality verification level has become the specification most widely referenced for sport diving. CGA Grade "E" is generally considered to be the absolute minimum acceptable breathing gas quality for SCUBA diving, and many consider it to be too liberal. Filling an "Oxygen Clean" cylinder with CGA Grade "E" will introduce hydrocarbon contamination such that the cylinder is no longer considered O2 clean and may not be used for partial-pressure blending.

* "Oxygen-Compatible" is CGA Grade "E" with reduced maximum acceptable carbon monoxide, hydrocarbon and particulate levels. The International Association of Nitrox Divers (IANTD) and American Nitrox Divers International (ANDI) created this designation for gases used in technical diving and gas blending. The U.S. Navy and the American Academy of Underwater Sciences (AAUS) have also issued "Oxygen-Compatible" specifications. All the "Oxygen-Compatible" specifications are similar but not identical. For the purposes of this discussion we'll use the IANTD "Oxygen-Compatible"