Scuba

why? or how? you have many elements that make scuba diving safe. being aware of your limitations such as amount of time you can dive, the speed of descending and ascending in the water, using the buddy system where you have someone with you under water, a gauge to monitor your air level, you learn certain hand signals to communicate to your buddy in order to understand each other in case your out of air or there is a problem. also knowing weather conditions such as water currents that could drift you from your boat or land. the biggest part of being safe is being aware of your surroundings and well aware of the training material when you get certified.

It depends entirely on the circumstance - how deep was the dive, how long, how long was the ascent etc etc.

Oxygen can not penetrate to great depth.

I don't see why not. The Duke of Edinburgh Award encompasses many different skills and I think Scuba diving would be afab one to do. When I done my gold award I used cross stitch embrodiery for mine!! good luck..

The biggest challenges is oxygen and nitrogen concentration. Oxygen becomes toxic at two atmospheres or about 300 feet since it is 1/5 atmosphere at the surface. Nitrogen is dangerous at lower concentrations if the diver doesn't rise very slowly. It also become like a narcotic about that depth. It is possible to regulate the concentration and use helium and selected gases and you can go down to at least about 1500 feet.

LOW PRESSURE HOSE:

Yes, a low pressure hose. A high pressure hose has a very small diameter opening since it is just used to measure pressure and it is not performing any work. A low pressure hose is used to perform work and has a larger diameter opening so air can move through it.

The quick answer is that a diver breathing air should descend no deeper than about 218 feet of seawater due to concerns of oxygen toxcity.

Here's the longer answer:

Oxygen can become toxic to a diver as the partial pressure of the gas increases with increasing depth. The point at which this occurs varies based on the metabolism of the individual diver and time at depth. A general rule of thumb is 1.6 atm PPO2. The NOAA Diving Manual quotes the following maximum times at various oxygen partial pressures:

1.6 45 minutes

1.5 120 minutes

1.4 150 minutes

1.3 180 minutes

1.2 210 minutes

It is important to understand that these are not fixed limits. An individual diver's reaction to high pressures of oxygen varies greatly. Most mixed gas rebreathers are set to maintain 1.2 to 1.4 PPO2, allowing for this variability.

To understand what this means to a diver in terms of maximum depth, we need to understand how depth affects the partial pressure of oxygen. The partial pressure of any gas is the total pressure the gas is under, times the fractional percentage of the gas. Each foot of seawater increases the total pressure of the breathing gas by .030303 atm. This means that the total pressure at 33 feet is 2 atm (1 at the surface plus one of water). Total pressure at 66 feet is 2 atm, 99 feet is 3 atm, and so on.

Since air is about 21% oxygen, the PPO2 of air is .21 at the surface, where the total pressure is 1 atm. At a depth of 33 feet of seawater, the total pressure is 2 atm, making the PPO2 (2 X .21) or .42. Accordingly a PPO2 of 1.6 is reached at about 218 feet of sea water. This depth, 218 fsw, is generally considered the maximum safe depth for a diver breathing air.

The same formula can be used for other breathing gases. A diver breathing pure oxygen reaches 1.6 PPO2 at about 20 feet of seawater. A diver breathing Nitrox32, containing 32% oxygen, reaches 1.6 PPO2 at 132 feet.

Note that much of this is moot for most recreational divers. Recreational dive training agencies set a maximum depth of 40 meters (130 feet) for a variety of reasons including avoidance of decompression illness.

Scuba gear comes in many different colors. Most scuba suites are black but they do make them in other colors some women like pink. You can get your mask and fins in a variety of colors from blue to yellow to red. Scuba gear has come along way and offers multiple choices.

Black Dog Divers is in Tempe, AZ and Andy teaches his diving classes at Sport Chalet in Tempe, AZ. Check out http://www.blackdogdivers.net

Scuba buoyancy is the most fundamental diving skill. Mastering buoyancy control enables a diver to use less effort to maintain his position while diving.

So that the divers are able to take pictures, provide research, and monitor the sea life and the changing temperature

One of the major advantage of personal submersibles over scuba gear is you can't feel the changing pressure while ascending and descending.

Oxygen toxicity can cause seizures and spasms. That implies to me that flickering eyes may be a symptom of O2 toxicity, but not a common or likely one. While possible, I'd personally look elsewhere for the cause.

Yes, extremely thick plate glass has been used for windows, and glass is also utilized for external cameras.

There is no depth limit, so as deep as a diver can stay comfortably warm in that particular suit in the water temperature.

Jacques Cousteau was very famous in developing early diving technology. He invented equipment and did a lot of marine research especially into underwater habitats. He is famous not only as a diver but as a film maker and marine explorer.

Divers use substances with high density (ie. lead) to help them sink, and substances with low density (ie. air) to help them float. That way they control their bouyancy.

By re-compression in a hyperbaric chamber with set periods of breathing 100% oxygen- the treatment plans are called 'Tables' and there are about 4 tables that are used to treat DCS.

Some props you might see in dive environments are pool toys, or in real environments it could be anything from a small plane to a large navy vessel.

PADI and most other agencies recommend the limit be 60'.

It has to do with the change in pressure on the body. The Bends happen when the body experiences a quick decrease in pressure. We mostly associate The Bends with a diver ascending too quickly from a deep depth back to the surface. But "decompression sickness", as it is more formally called, can happen from changes in altitude, too, or even after exiting mines and going back to the surface.

A red flag with a diagonal white stripe

There is no minimum interval. A dive directly from 70 fsw for 29 minuts can immediately be followed to a dive to 50 fsw for 39 mins, and would be classed as a "Combined Dive"

To calculate decompression from this Combined Dive, is by taking the depest depth, (70 fsw), and total time (68 mins), and decompress on an appropriate table.

Using the USN repetitive dive times, this varies on the residual nitrogen remaining in solution.