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Aquatic Science Dive Test
Klein Oak High School- Aquatic Science- Mr. Christian
Terms in this set (47)
What was the first effective means of staying underwater?
What diving technology did the US navy adopt in 1917?
The Mark V Diving Helmet. (a deep diving suit)
Who invented the aqualung?
Cousteau and Gagnan
What reduces the high pressure in the diving cylinder to ambient pressure?
The function of the "demand regulator" attached to the diving cylinder is to reduce the high-pressure gas supplied by the scuba cylinder to the ambient pressure surrounding the diver at depth.
What is a BCD and what is its purpose?
A buoyancy compensator device. Almost all BCDs are worn like a vest and include a band for mounting the air cylinder. The BCD contains an air bladder that the diver inflates or deflates to maintain control over buoyancy, thereby avoiding uncontrolled ascents and descents.
State the principal of buoyancy.
An object placed in water is buoyed up by a force equal to the weight of the water displaced. As an object is submerged it displaces a quantity of water equal to its volume.
What does Boyle's law tell us?
Boyle's law states that at a constant temperature, the volume of gas will vary inversely with pressure, while the density of the gas varies directly with the pressure. This pressure pushes in on flexible air spaces (such as your ears) compressing them and reducing their volume. The reduction of the volume is proportional to the amount of pressure and therefore the depth. When the total pressure is double the surface pressure, the air volume is halved. When the pressure is triple the surface pressure, the volume is reduced to one third, and so on.
How many atmospheres of pressure is a diver exposed to at 99 feet?
How does one maintain an air space at its original volume when pressure in increased?
To maintain an air space at its original volume when pressure is increased, more air must be added to the space.
What can happen if you hold your breath on ascent from a dive?
Pressure also comes into play as a diver ascends. At depth, the air in the lungs is compressed and more dense, as the diver ascends the air expands and can over-inflate the lungs producing serious injury or death. NEVER hold your breath when scuba diving, ascend slower than the smallest bubbles and continue to breath. Remember that a breath of air from a tank at 33 feet will double in volume as you approach the surface. An injury produced from pressure is referred to as barotrauma.
What is the composition of our atmosphere?
78% nitrogen and 21% oxygen.
What two conditions are a result of Henry's law and nitrogen?
In 1876, Englishmen, Henry Fleuss invented a closed circuit, oxygen rebreather. His invention was originally intended to be used in the repair of an iron door of a flooded ship's chamber. Fleuss then decided to use his invention for a thirty-foot deep dive underwater. He died from the pure oxygen; oxygen is toxic to humans under pressure.
Why are objects closer and larger when using a dive mask?
As the light travels from the water into the mask it is refracted slightly and as it travels from the air in the mask into your eye it is refracted again. The net result is that objects are in focus but magnified, objects appear 25% larger and closer.
Why is red the first wavelength of light absorbed by water?
Water absorbs light so as you descend there is less light. Because it is absorbed by wavelength the colors contained in white light (ROYGB) are absorbed at different depths. Red has the longest wavelength and lowest energy so it is absorbed the most and is therefore not present below about 30 feet. At depth, red objects appear brownish, gray, or black.
Breathing air at depths over 100 feet can cause this-
Reduces cylinder pressure to about 140 psi-
Travels farther in water than air-
14.7 psi equals one of these-
The number of atmospheres experienced by a diver at 33 feet of depth-
Self contained underwater breathing apparatus-
Used to calculate nitrogen content in tissues-
Breathing high consentrations of this gas at depth is toxic-
Doubles in the first 33 feet when diving-
Color of light absorbed first as depth increases-
Hold your nose and swallow-
Method used to relieve ear squeeze-
Used more rapidly the deeper you dive-
How many times faster sound moves in water than air-
Buoyancy experienced when you displace a volume of water that is less than your weight-
Number of feet required for an increase of one atmosphere-
Seventy eight percent of atmosphere-
What increases about the air in your lungs when free diving-
Type of buoyancy experienced when an object displaces a volume of water equal to its weight-
Reduces intermediate pressure to ambient pressure-
Illness caused when nitrogen bubbles form in tissues as pressure is reduced-
Used to treat decompression sickness-
First effective means of staying underwater-
Makes objects appear twenty five percent larger and closer-
Injury produced by pressure-
Relieved by breathing out of your nose-
Name given to the first scuba diving system-
Buoyancy compensating device-
What happens to the volume of gas as pressure is halved-
Force on an object equal to the weight of the water displaced-
US Navy diving system used well into the 1980's-
As pressure on a gas increases, what decreases-
What you should never hold when diving-
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