Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
78 Cards in this Set
- Front
- Back
When diving in tropical waters, what potential danger is often ignored to the divers regret?
|
Sunburn
|
|
Name 5 non-aggressive, but potentially harmful, sea creatures.
|
Shark, moray eel, sting ray, sea urchin, fire coral, portuguese man-o-war, jelly fish, octopus, barracuda
|
|
Give 3 water conditions that would prohibit ocean diving.
|
Current, tides, visibility, wave, surf, pollution.
|
|
Why does the moray eel pose a particular threat to divers gathering lobsters?
|
The eel and the lobster live in the same holes and crevices. A diver may reach into one of these holes while seeking a lobster and get bit by the eel.
|
|
When diving in tropical waters, what procedures would you use to avoid stings and injury from a Portuguese Man-O-War or a jelly fish?
|
By using your octopus and "blowing" them away. Look up and circle 360 degrees as you ascend to the surface
|
|
How would you recognize fire coral and why would you want to avoid it?
|
Mustard yellow with white tips. Takes on form of various corals, has many stinging cells.
|
|
What are 2 ways to avoid injury from a sting ray?
|
1)Shuffle feet in water when entering a beach area. 2) Do not swim close to bottom.
|
|
Explain the proper procedure to follow if caught in a "rip-current".
|
Inflate your B.C. and ride with the current If possible, swim perpendicular to current until our of it.
|
|
What is the danger of touching a stone fish/ scorpion fish?
|
Their defense is being able to blend into the bottom. Their dorsal spines contain a toxin which can be fatal to humans.
|
|
Why would a diver want to make a night dive?
|
Different forms of life come out to feed, opportunity to see nocturnal animals..
|
|
Air is a mixture of several gases. State the two main components and their relative percentages of the mixture.
|
Oxygen: 20%
Nitrogen: 80% |
|
What is the pressure increase per foot of depth, in psi for: 1)Salt water 2)Fresh Water
|
S.W. .445 psi/ft
F.W. .432 psi/ft |
|
One half cubic foot of salt water displaced will give a buoyant force of how many pounds? What law is this related to?
|
(64 lbs/ft cu.)x(.5 ft cu.) = 32 lbs
Related to Archimedes Principle |
|
One half cubic foot of fresh water displaced will give a buoyant force of how many pounds?
|
(62.4 lbs/ft cu)x(.5 ft cu.) = 31.2 lbs
Archimedes Principle |
|
What is Boyle's Law?
|
Pressure and Volume are inversely related. As pressure increases, volume decreases, and vice versa...
|
|
The pressure at sea level is equal to what? (in psi and in atm)
|
14.7 psi which equals 1 atm
|
|
Describe the difference between absolute pressure and gauge pressure.
|
Gauge pressure tells the pressure of the surrounding water, absolute pressure includes the 1 atm of pressure from the above air.
|
|
What is the #1 rule of scuba diving?
|
Never Hold Your Breath!
|
|
State Henry's Law.
|
The solubility of a gas in a liquid is almost proportional to the partial pressure of that gas.
|
|
How does Henry's Law relate to scuba diving?
|
At increased depth (and pressure), more Nitrogen from the air goes into solution in the diver's body tissues.
|
|
A diver fills his balloon with air from his tank at a depth of 66ft(salt water). What will the volume be when brought to the surface?
|
V2=(D1+33)xV1/(D2+33)
V2=(66+33)x 2/(0+33) V2=99 x 2 / 33 V2=6 ft cu. (1/3 the pressure, 3x the volume) |
|
A diver fills his tank to 3 cubic ft of air in his tank at 99 ft of fresh water. What will the volume be when brought to the surface?
|
V2=(D1+34)xV1/(D2+34)
V2=(99+34)x 3/(0+34) V2=133 x 3 / 34 V2= approx 12 ft cu.(1/4 the pressure, 4x the volume) |
|
What 2 problems can Nitrogen cause when scuba diving?
|
1) Nitrogen Narcosis
2) Decompression Sickness (the Bends) |
|
What is the sequence of colors to be filtered out as you descend?
|
ROY G BIV
(red, orange, yellow, green, blue, indigo, violet) |
|
Why will a diver become chilled in 80 degree water?
|
Water transfers heat away 25x faster than air. 80 degrees is 18 degrees cooler than our body temp (98.6)
|
|
How much larger and closer to objects appear in water?
|
1/3 (33%) larger, and 25% closer.
|
|
Does sound travel faster in air or water? How does it affect a diver?
|
Travels 4x faster in water. Makes it difficult to distinguish what direction sounds are coming from.
|
|
What is the absolute pressure, in psi, at 100 ft of salt water?
|
P=(D+33)x.445
P=(100+33)x.445 P=133x.445 P=59.2 psi |
|
What is the absolute pressure, in psi, at 66 ft of fresh water?
|
P=(D+34)x.432
P=(66+34)x.432 P=100x.432 P=43.2 psi |
|
What are alveoli and what are their function?
|
Alveoli are the small sacs found in the lungs where gasses are exchanged between the inhaled air in the sacs and the capillaries surrounding the sacs.
|
|
When diving, what is the pressure of the air we breathe from the regulator?
|
The regulator delivers air to the diver at the ambient water pressure.
|
|
What is the function of the Eustachian tube, and why do divers care about it?
|
It connects the middle ear cavity to the back of the throat. It maintains pressure between the out and middle ear which are separated by the ear drum.
|
|
What is squeeze?
|
The affect of unequalized pressure on any of the body's internal or attached crevices.
|
|
What are some examples of parts affected by "squeeze"?
|
Ear, sinus, thoracic, tooth, intestinal, mask, hood, and suit squeeze.
|
|
Will a tank of air last longer at a depth of 30ft or 90ft? Why?
|
30 ft. It takes almost twice as many air molecules to fill your lungs at 90 ft as at 30 ft. (Boyle's Law)
|
|
What is the danger of diving with a head cold?
|
1) Sinus squeeze
2) Ruptured ear drum |
|
What is the danger of taking decongestants before a dive?
|
If the decongestant wears off during the dive, you may encounter reverse squeeze, and may not be able to clear ears and/or sinuses on ascent.
|
|
Describe two possible ways of rupturing an ear drum.
|
1) Not clearing the ears during descent.
2) Hood squeeze |
|
How does a diver avoid mask squeeze?
|
Exhale into mask during the descent in order to equalize pressure between inside of mask and surrounding water.
|
|
What should a diver do when he/she encounters ear or sinus squeeze?
|
Ascend until symptoms disappear, if ears or sinuses don't clear after several attempts to descend, abort dive.
|
|
What is the Valsalva Maneuver?
|
Pinch nose and exhale in order to equalize pressure in ears.
|
|
What is the Toynbee Maneuver?
|
Pinch nose, close mouth and swallow to equalize pressure in ears.
|
|
What do you experience when an ear drum blows?
|
Causes vertigo: disorientation, loss of balance
|
|
At 130ft your buddy starts acting funny: a) what do you do? b) what is the name of this problem? c) what is the cause of this problem?
|
a) Get your buddy to ascend 20-30 ft or until he behaves normally. b) Nitrogen Narcosis. c) Breathing nitrogen at a high partial pressure.
|
|
Name 2 ways a scuba diver can incure Oxygen poisoning.
|
(occurs when breathing Oxygen at a partial pressure above 1.5 atm) 1) compressed air below 218ft. 2) Nitrox below recommended depth 3) oxygen rebreather below 33ft
|
|
What is the primary sign of Oxygen poisoning?
|
Convulsions
|
|
What is the danger facing a skin diver who hyperventilates excessively before a deep dive?
|
Shallow Water Blackout
|
|
During a dive, you are working hard and begin to feel anxious and out of breath, a) what do you do, b) What do you think the problem is?
|
a) slow down and catch your breath. b) carbon dioxide buildup.
|
|
When breathing from a new tank, the air has a burnt or oily taste, a) what is the risk of using the tank? b) what could cause this strange taste?
|
a) carbon monoxide buildup b) dieseling in the compressor, or air inlet to compressor is too close to a source of engine exhaust
|
|
What is hypoclycemia? How can it be prevented?
|
Hypoglycemia is low blood sugar. In scuba, usually result of poor diet. To avoie eat healthy meals before diving.
|
|
Descibe symptoms of vertigo and give to possible causes.
|
Symptoms include spatial disorientation, dizziness, and nausea. Caused by ruptured ear drum, lack of visual reference, and ascent vertigo.
|
|
A skin diver fills his lungs to 10 pints, then dives down to 20 ft in the ocean, what is the volume of air in his lungs at 20 ft?
|
V2=((D1+33)xV1)/(D2+33)
V2=((0+33)x10)/(20+33) V2=(33x10)/53 V2=330/53 =approx 6 pints |
|
Calculate partial pressure of Oxygen in 67 ft of salt water. (in psi)
|
P02 = (D+33) x .445 x .2
P02 = (67+33) x .445 x .2 P02 = 100 x .445 x .2 P02 = .089 psi |
|
A sport diver has developed a case of the bends. What mistake has the diver made?
|
Stayed too deep for too long.
|
|
List 3 things to prevent getting the bends.
|
Plan dive/dive plan
don't dive too deep drink plent of fluids before ascend properly make a safety stop |
|
What are the primary symptoms of the bends?
|
Pain in the joints after dive, fatigue, skin itches, dizziness, numbness, tingling, paralysis...
|
|
What is the medical treatment for the bends?
|
Use 100% oxygen with a demand regulator. Then recompression chamber.
|
|
A sport diver has developed an air embolism. What mistake did the diver make?
|
Not properly vented air volume building in lungs. Held breath on ascent.
|
|
How could a diver prevent getting an air embolism?
|
Don't hold breath, breath normally, don't dive if lungs are congested, ascend at 30ft/min or slower.
|
|
What are the primary symptoms of an air embolism?
|
Unconsciousness and/or bloody froth in mouth.
|
|
What is the treatment for an air embolism?
|
100% oxygen on demand regulator, then recompression chamber.
|
|
Where are are the bubbles lodged in a diver with a ruptured lung for the followin: a) air embolism, b) subcutaneous emphysema, c) mediastinal emphysema, d) pneumothorax ?
|
a) brain b)under the skin of the neck and shoulders, c) center of chest cavity surrounding heart, d) between lungs and the walls of the chest cavity
|
|
What is the recommended safe rate of ascent for a diver?
|
30 ft/min or slower.
|
|
What are the 2 types of nitrogen narcosis?
|
warm/clear water: euphoric joyous sensation. cold/low visibility water: melancholy, gloomy, fearful.
|
|
What is a major problem of nitrogen narcosis?
|
Divers indifference to following safety precautions!
|
|
What are symptoms of Carbon dioxide excess?
|
Cyanosis (blue-black discoloration of the skin, lips, nails), rapid breathing, headache, dizziness, vommiting.
|
|
How do you prevent carbon dioxide buildup?
|
Normal deep and continuous breathing. Avoid heavy exercise. If breathing hard, slow and catch breath.
|
|
What are the 3 triggers that urge us to breathe?
|
1) High carbon dioxide level
2) Low partial pressure of oxygen 3) Decreased lung volume. |
|
By law, how often must a SCUBA tank be hydrostatically tested?
|
Every 5 years
|
|
How often must tanks be visually inspected?
|
Every year
|
|
What is the purpose of a "burst disk" in a tank?
|
Part of the tank valve which will rupture at a certain pressure, safely venting the tank.
|
|
Why should you always return from a dive with 500 psi remaining in your tank?
|
1) safety: it's important to have some reserve, just in case. 2) prevent moisture from getting into the tank.
|
|
Why shouldn't you breath a tank dry?
|
Having some air in tank prevents moisture from getting in.
|
|
What is the approximate pressure in the 1st stage of a 2-stage regulator?
|
140 psi (120-180 psi)
|
|
What is the approximate pressure of the 2nd stage of a 2-stage regulator?
|
The ambient pressure at the 2nd stage.
|
|
What is the difference between a "J" valve and a "K" valve?
|
K = on/off
J = constant pressure reserve (about 300 psi) |
|
What is the purpose of a "dust cap"?
|
To keep moisture out of the first stage of the regulator.
|
|
What information can you obtain from the markings on the neck of a tank?
|
Date of manufacture, manufacturer, material, serial number, subsequent hydro dates, working pressure
|