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175 Cards in this Set
- Front
- Back
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an object is positively bouyant when:
a. it displaces a volume of water weighing less than its own weight b. it displaces a volume of water weighing more than its own weight c. it displaces a volume of water weighing equall to its own weight. |
b. it displaces a volume of water weighting more than its own weight.
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what two peices of equipment do you use to control your bouyancy?
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BCD and Lead weight
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buoyancy controls is on of the most important skills you can master because it allows you to control where you are in the water. True or Flase?
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True
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an object will be more bouyant in ___ water than it would be in ___ water.
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salt water than in fresh water.
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when you exhale, your lung volume decreases. this means oou have ____ buoyancy.
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less
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you usually feel pressure only in body air spaces because:
a. your body is moslty made of incompressible liquid, but air is compressible and changes volume with pressue changes. b. water is denser than air, which resists prssure better. |
a.
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pressure changes in water for a given ascent or descent are much more substantial than the same distance ascent or descent in air because water weights more. True or False?
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True
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what are the absolute pressure, in atmospheres or bar, for:
a. 10metres/33ft b. 20metres/66ft c. 30metres/99ft d. 40metres/132ft |
a. 2 bars/ata
b. 3 bars/ata c. 4 bars/ata d. 5 bars/ata |
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what are the volume of air and density of air at these depths?
a. 0metres/0ft b. 10metres/33ft c. 20metres/66ft d. 30metres/99ft e. 40metres/132ft |
volume:
a. 1 b. 1/2 c. 1/3 d. 1/4 e. 1/5 density: a. x1 b. x2 c. x3 d. x4 e. x5 |
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the three major ait spaces affected by pressure when you descend are what?
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mask, ears, and sinuses
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a pressure imbalance in which pressure outside an air space exceeds pressure inside an air space, resulting in pain or discomfort
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squeeze
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adding air to an air space as you descend so the pressure in an air space equals the surrounding water pressure
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equalization
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what are the techniques for equalizing your ears?
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pinch you mose and blow gently against it
swallow and wiggle your jaw from side to side |
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when do you want to equalize your ears?
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every metre/ft before you feel discomfort
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if you feel discomfort and can't qualize, ascend until you relieve the discomfprt and try again. Don't be forceful in equalizing. If you can't equalize, discontinue the dive. True or False?
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True
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what is the most important rule in scuba diving?
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breathe continuously and never hold your breath.
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what can ascending while holding your breath cause?
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lung over expansion injuries and serious injuries like paralysis and death
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pain and discomfort cused by expanding air trapped inside an air space during ascent.
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reverse block
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if you feel discomfot during ascent due to a reverse block you should do what?
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slow or stop you acent and give the trapped ait time to work its way out.
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the deeper you go the ___ you use up air supply.
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faster
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you need a mask to see underwater because:
a. the human eye can't focus in water b. the mask specially filters the light underwater c. the mask is an important part of looking really sharp. |
a.
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a mask needs to enclose you nose:
a. for a better feild of view b. so you can equalize the mask c. so you can pinch you nose and equalize you ears. |
b.
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the features you look for in a mask include what?
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low profile, nose or finger pockets, and wide vision field
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the most important factors when buying a mask are what?
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fit and comfort
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to prepare a new mask for use you:
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scrub off the protective film left from manufacturing and adjust the strap
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maintenance for you mask include:
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rinsing in fresh water after use and storing in a cool, dry place
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why do you need a snorkel when scuba diving?
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to conserve air while swimming or resting at the surface,
to make it easier to breathewhen the surface is a bit rough, and in case you have a long swim with an empty cylinder |
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what does an easy breathing snorkel have?
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lorge bore and smoth, round bends
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where does the snorkel sit?
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at the left side of your mask
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fins help you move more effectively by letting you use your leg muscles to swim. True or False
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True
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of the three styles of BCD, the one recreational divers use the most commonly is:
a. jacket style b. back mount c. front mount |
a. Jacket style
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what additional maintenance requirements do you have with a BCD?
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rinse the interior with fresh water and store partially inflated
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the two metals scuba cylinders are commonly made from are:
a. aluminum and copper b. aluminum and steel c. copper and steel |
b. aluminum and steel
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A ___ valve is an on-off valve, and a ___ valve has a built in reserve.
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K, J
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you connect a regulator to a ___ by screwing it into the valve.
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DIN
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relieves pressure from an overfilled or heated cylinder.
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burst disk
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a regulator reduse high pressure cylinder air in ___ steps
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two
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a _____ needs an annual visual inspection and periodic pressure testing.
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scuba cylinder
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a regulator's most important feature is ____.
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ease of breathing
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the _____ tells how much air you have at any time during the dive.
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SPG
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whats the best way to prevent water from entering you scuba cylinder?
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never allow your cylinder to completely empty
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underwater, what you look at will be:
a. larger and/or farther away b. smaller and/or closer c. smaller and/or farther d. larger and/or closer. |
d. larger and/or closer
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water absorbs light, causing it to get ___ as you go deeper and colors become ____ vivd with dept.
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darker; less
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underwater, sounds:
a. don't travel very far. b. are easy to locate. c. often seem to come from directly overhead |
c.
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water absorbs heat about ___ time faster than air.
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20
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beginning to shiver continuously means what?
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you should immediately end the dive, dry off and seek warmth.
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whats the best way to move underwater?
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slowly and smoothly, relaxed.
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for maximum efficiency, underwater you should breathe how?
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slowly and deeply
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what are some symptoms of overexertion?
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labored breathing, euphoria, a feeling of suffocation
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what do you do to prevent overexertion?
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pace yourself, know your limits, and avoid prolonged heavy exertion
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what are some techniques for airway control?
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inhaling slowly if water enters your regulator, inhaling cautiously after clearing your regulator or snorkel, and using your tongue as a splash guard.
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the twp reasons for waring an exposure suit are what?
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thermal protection and to protect
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a ___ suit insulates you with a layer of neoprene against your skin, whereas a ___ suit nsulates you with a layer of air and other insulating material.
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wet, dry
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a wet suit must fit snugly to do what?
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minimze water circulation and retain heat
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as you go deeper, a wet suit may lose what two properties?
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buoyancy and insulation
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when purchasing an exposure suit, you need to consider what?
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fit, comfort, and thermal protection
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to care for you exposure suit, you should do what?
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rinse it after each use,
dry inside out, and store on a hanger |
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you need a hood b/c as much as ____ persent of body heat loss can occur there.
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75%
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you shouldn't wear an excessively tight hood b/c why?
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it can make you faint
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why do you wear gloves?
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insulation and protection
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to prevent overheating before a dive you should:
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put your suit on at the last possible moment,
keep your hood off as long as possible, and cool off in the water |
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what are the two types of weight systems?
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weight belt and the integrated weight system
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what is the most important feature of a weight system?
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a quick release
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if your'e properly weighted, you will what?
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float at eye level with an empty BCD and holding a normal breath
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what is an alternate air source?
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any mouthpiece, other than your primary, that you can ascend with while breathing nromally
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the ___ is an example of alternate air source that requires buddy assistance
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alternate second stage
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it is important to mark your alternate air source clearly so:
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you or a buddy can locate it without confucion in an emergency
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you want to secure the alternate air source how?
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in the triangle formed by your chin and the corners of your rib cage.
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you need a low pressre inflator to do what?
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to allow you to quickly and easily inflate your BCD with one hand.
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you need a dive knife for what?
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as a practicle tool and for saftey
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what are the three features to look for in a dive knife?
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smooth edge, serrated edge, and sheath
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what is ideal way to pack our bad for diving?
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in the reverse order in which you will need it.
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the reference information you get from dive instruments include what?
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time, temp, and direction
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underwater timepieces can be what?
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dive watches and bottom timers
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you need a depth gauge because
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underwater times limits relate to depth
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determines your dive time remaining based on your depth and the elapse dive time
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dive computer
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what are some reasons for having an underwater compass?
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determining where to find your exit point and following a course
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to get your buddy's attention underwater you can touch your buddy or ___.
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rap on your cylinder
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what are the two methods of communicating underwater?
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hand signals and slate
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if you receive an underwater recall, you should do what?
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cautiously surface and look to the boat for instructions, or as directed in the briefing.
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dive plan considerations to discuss with your buddy include what?
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dive objective, what to do if separated, time and depth limits, and the course to follow
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the BWRAF of the predive safety check stands for what?
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BCD
Weights Releases Air Final okay |
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if you lose contact with your buddy, the general procedure is what?
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search no more than a minutes, then reunite on the surface
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since it travels about ___ times faster in water than in air, you will have difficulty determining the origin of sound underwater.
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four times
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conditions that can affect you as a diver in any aquatic environment inculde:
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sunlight, temp, water movement, and bottom compostition
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as you descend, most commonly you can expect a temperature change to ___ water.
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cooler
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an abrupt change to a layer of colder water.
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thermocline
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the approximate distance you can see horizontally.
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underwater visibility
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what are some factors that affect underwater visibity?
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water movement, suspended particules, and bottom composition
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restricted visibility can cause what?
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buddy separation, disorientation, loss of direction
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when diving in clear water, it's recommended that you:
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use a line or other reference when ascending and descending
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what are some causes of currents?
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waves, wind and tides
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under most circumstances, if there's a current you should begin your dive:
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swimming against the current
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if a current carries you past your planned exit point you should
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swim across the current to some other exit point, a line trailed from the boat, or out of the current.
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when diving from a boat, of ou get exhausted and caught in a current at the surface, you should:
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establish positive buoyancy, signal for help and rest.
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what are six bottom compositions?
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1. silt
2. mud 3. sand 4. rock 5. coral 6. vegetation |
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to avoid bottom contact you do what?
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remain neutrally buoyant and seim with you feet up off the bottom
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what are the two types of interactions you can have with aquatic life?
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passive and active
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nearly all injuires from aquatic life result from what?
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diver carlessness
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if you sight an aggressive animal underwater, you should watch it and leave the area calmly on the bottom if it remains or appears aggressive. True or Flase
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true
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what are three precautions you can take to avoid injury by an aquatic animal?
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1. wearing an exposure suit and gloves
2. watching where you put your hands, feet and knees 3. not touching anything you don't recognize |
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you don't have to worry about sunburn when it's overcast, or when you're in the water. True or False
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False
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Freshwater dive considerations include what four things?
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deep water, altitude, thermoclines, and limited visibility
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saltwater dive considerations include what four things?
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surf, tides, marine life, and waves
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____ create surge, which you avoid by ____
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waves, going deeper
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longshore currents tend to do what?
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push you parallel to the shore
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how can you recognize a rip current?
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1. turbid, foamy water
2. strong flow away from shore 3. disruption of the waves |
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If you are caought in a rip, you should do what?
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swim parallel to shore
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an upwelling tends to cause ___ dive conditions.
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excellent
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How do tides affect diving conditions?
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causing currents and affecting visibility
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generally, the best tidal level fo diving is low tide or high tide.
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high tide
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How do you divide dive planning?
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advance planning, preparation, last minute preparation, and predive planning
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what are the three steps in advance planning?
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1. choosing a buddy
2. agreeing on an objective 3. agreeing on logistics |
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in the preparation you ___ need to inspect your equipment.
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do
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what are three last minute preparations?
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1. letting someone know where you're going and when you plan to return
2. packing items like ice chest, jackets, etc. 3. checking the weather |
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what are three benifits from diving from a boat?
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1. reaching dive sites inaccessible from shore.
2. avoiding long surface swims 3. fun |
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the ___ is the front of the boat; the __ is the bathroom.
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bow, head
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panicked divers typically do what?
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push off their masks and spit out thier regulators and need immediate help
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The general best all round option if you run out of air is to do what?
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use an alternate air source
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to breathe from a free flowing regulator you do what?
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don't seal your lips around the mouthpiece and allow excess air to escape
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if you become entangled underwater, your first response should be to do what?
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slowly untangle yourself
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what should you do if a diver becomes unresponsive underwater?
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bring he diver immediately to the surface and check for breathing
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nearly all injuries from aquatic life are caused by ___ action on the part of the animal
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defensive
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a rip current ca be recognized as a lline of turbid, foamy water moving what direction?
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seaward
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what are the five low-on-air/out-of-air emergency procedures in order of priority?
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1. normal ascent
2. alternate air source ascent 3. controlled emergency swimming ascent 4. buddy breathing 5. bouyant emergency ascent |
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what are four uses for a dive float?
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1. assisting another diver,
2. resting, 3. supporting a dive flag, 4. and carrying accessories |
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what should you do to avoid entanglement with a line to your surface float?
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use a reel of line caddie
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what are two reasons you sould use a dive flag?
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it warns off boaters and local law may require it
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if no laws stipulate otherwise, the rule of thumb is that you should stay withing ___ of your dive flag, and boaters should stay ____ away.
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15metres/50ft; 30-60 metres/100-200ft
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reasons for keeping a log book include :
a. documenting your history as a diver. b. that it's required to keep your certification c. recording specific dive site details d. helping you remeber your experiences |
a., c., d.
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Before a dive you want to avoid what?
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drinking, smoking, and drugs
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it's recommended that you have a complelt physical examination every ___ yrs.
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two
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immunizations divers should keep up to date are ____ and ____.
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tetanus and typhoid
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it recommended that pregnant women dive or don't dive?
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don't dive
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the two primar gases that make up air are what?
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oxygen and nitrogen
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symptoms of contaminated air include what?
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headache, nausea, and cherry red lips/nail beds
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if a diver is suspected of breathing contaminated air you should do what?
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give the diver fresh air and oxygen if available and get medical attention
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you avoid contaminated air problems by having your cylinder filled only by a reputable air source with a compressor system intended for breathing air. True or False?
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True
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what are three symptoms of nitrogen narcosis?
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false sense of security, foolish behavior, and anxiety
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if nitrogen narcosis becomes a problem you should do what?
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ascend to a shallower depth
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to prevent nitrogen narcosis you should do what?
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avoid deep dives
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what are the two primary factors influencing how much nitrogen ou absorv during a dive?
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dive time and dive depth
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the condition that ooccurs when a diver exceeds established depth and time limits, producing bubbles in the body following ascent, is called what?
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decompression sickness
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secondary factors that can influence nitrogen absorption and elimination include what ?
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alcohol consumptiong before or immediately after dive, dehydration, age, and being overweight.
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signs and symptons of decompression sickness include what three things?
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1. limb and joint pain
2. mild tingling and fatigue 3. paraysis and inconsciousness |
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a clinical terms that means bothe decompression sickness and lung over expansion injuries.
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decompression illness
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a diver with decompression illness requires treatment how?
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in a recompression chamber
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what are four first aid for decompression illness?
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1. emergency oxygen
2. lying on the left side if unresponsve and breathing 3. contacting local emergency medical care. 4. contacting a dive physician or local diver emergency service |
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how do you reduce the risk of decompression sickness?
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staying within the limits provided by your dive table or computer, diving conservativel, and making slow safe ascents.
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air is __ % nitrogen and ___ % oxygen.
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79 N and 21 O
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what is the primary use of dive tables and dive computers?
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tell you the allowable dive time at a given depth
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no decompression diving means that you can do what?
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ascend directly to the surface at any time without significant risk of DCS
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a no decompression limit means what?
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the max time you can spend at a given depth and still make a no decopression dive
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why should you avoid the max limits of dive tables and dive computers?
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ppl differ in their susceptibilty to DCS
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why does the RDP differ from other tables?
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it was designed specifically for recreational no decompression diving
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nitrogen that remain in your body for several hours after a dive is called what?
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residual nitrogen
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the time from when you leave the surface to the time when you leave the bottom for your final ascent to the surface.
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bottom time.
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what does being a SAFE diver mean?
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slowly ascend from every dive.
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what is the depth limit for scuba divers? open water divers? general recreational limits and max depth limit?
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scuba diving: 12m/40ft
open water: 18m/60ft genreal recreational diving: 30m/100ft maximum limit: 40m/130ft |
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according to the recreational dive planner, the no-decompression limit for 18m/60ft is __ minutes.
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one minute
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the recommended general depth and time for a safety stop is what?
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5m/15ft for 3 minutes
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what is the purpose for a saftey stop?
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to give your body extra time to eliminate nitrogen and to allow you to stablize and control your ascent.
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a safety stop is considered requires when?
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you dive to 30m/100ft or deeper
you reach any limit on your table or computer and your dive comes within three pressure groups of an NDL on the RDP |
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if you exceed you no decompression limit or adjusted no decompression limit by less than five minutes when using the RDP you should do what?
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slowly ascend to 5m/15ft and make an 8 minute stop then not dive for at least 6 hours
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if you exceed your no decompression limit or adjusted no decompression limit by more than five minutes when using the RDP, you should do what?
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slowly ascend to 5m/15ft and make a stpo for at least 15 minutes, air supply permitting, then not dive for at least 24 hours
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if you exceed the no decompression limit of you dive computer you should do what?
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make an emergency decompression stop as it directs in its decompression mode, and do nt make a repetitive dive
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when using the RDP, you need to use special dive procedures above what altitude?
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300m/1000ft
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the minimum recommended surface interval for flying after diving is ____.
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12 hours
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using the RDP, under cold and strenuous conditions you plan your dive as thought ___.
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it were 4m/10ft deeper than actual
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any dive that your computer provides no decompression dive time for is acceptable. True of False?
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False. your computer may provide data for dives that aren't recommended
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what are four basic features of an underwater compass?
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1. lubber line
2. compass needle 3. index marks 4. bezel |
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when using a compass, you want to align your body center line with what?
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the lubber line
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to navigate a straight line, point the ___ in your travel and direction and then put the ___ over the ____.
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lubber line; index marks over the compass needle
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to navigate a reciprocal heading, rotate the bezel so the ___ are/is exactly opposite the initial heading.
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index marks
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the compass ___ always indicates our travel direction; the compass ____ always points north.
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lubber line; needle
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