SDI Scuba Certification Exam Study Guide with Verified
Answers Graded A+
Define SCUBA - -S - self because water is about 800 times denser than
C - contained air.
U - underwater
B - breathing
A - apparatus
What is the first color to be absorbed
underwater? - -Red (within first 25 feet)
List 3 important scuba diving changes that
occurred in 1950s - -1) published USN
dive tables When diving from shore, the best time to dive is
2) invented the personal dive computer when there is the least amount of tidal current.
3) equipment manufacturers made improvements _______ tide is when there is no horizontal water
to the design and workmanship of gear movement. - -Slack tide
Name 3 different devices that modern dive If you are caught in a rip current, first swim _____
computers replace - -1) dive tables to the current to get out of it before swimming
2) J-valves towards shore. - -Parallel
3) depth gauges
Waves are usually caused by - -Wind
What sets SDI apart from other training pushing water on the surface
agencies? - -First dive training agency to
provide entry level scuba instruction that
incorporates the use of personal dive computers
--> more streamlined scuba course w/ more T or F: Anticipate surge action to avoid contact
instruction time in the water with stationary objects - -True
How much larger and closer do objects appear What type of marine life cause most diving
underwater and why? - -Objects injuries? - -Most diving injuries result from
underwater appear 25% larger and 25% closer animal's defensive response to a perceived threat
As light travels through the airspace created by
the mask, it bends, creating a magnifying effect.
What should you do if you see a potentially
dangerous animal underwater and it does not
leave the area? - -Remain still and calm.
How much faster does sound move through Slowly leave area if necessary.
water than air and why? - -4 times faster
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, SDI Scuba Certification Exam Study Guide with Verified
Answers Graded A+
in your ears upon descending? - -Stop,
ascend a few feet until you no longer feel
List three different reasons that it is advisable to discomfort, equalize again, then continue with
check with your local dive center before descent
conducting a dive in an area you are unfamiliar
with? - -1) tidal conditions
2) marine life
3) first aid for potential injuries in area What is a reverse block? - -When air
cannot escape freely from an air space during
ascent
What is the absolute pressure (in atm/bar) at 20 causes pain and discomfort in the ears and
meters (66 feet)? - -3 atm/bar sinuses
What will be the volume in a ball that is filled with What should you do if you experience a reverse
2 cubic feet/liters of air at 30 meters (90 feet) block upon ascending? - -Stop, descend a
when it is taken to surface? - -8 cubic few feet until pain subsides, wait to allow air to
feet/liter (4x the volume) vent, then continue with ascent
How many more times dense is the air in a ballon What is the most important rule in scuba diving? -
at 4 atm/bar compared to air density at surface? - -Breathe continuously and never hold your
-4x breath
If a scuba cylinder lasts two hours at sea level, What is the most serious injury that a diver could
how long will it last at 20 m/66 ft? - -40 suffer from if they hold their breath upon
minutes ascending? - -Lung over-expansion
120 min x 1/3 (vol) = 40 min
Which gas component in air causes
decompression sickness and narcosis? - -
How often should a scuba diver equalize during Nitrogen
descent? - -At the surface before descent
and every couple of feet
What medical problem can occur if a diver
ascends much too rapidly for nitrogen to be
What should you do if you experience discomfort slowly released? - -Decompression
2/8
Answers Graded A+
Define SCUBA - -S - self because water is about 800 times denser than
C - contained air.
U - underwater
B - breathing
A - apparatus
What is the first color to be absorbed
underwater? - -Red (within first 25 feet)
List 3 important scuba diving changes that
occurred in 1950s - -1) published USN
dive tables When diving from shore, the best time to dive is
2) invented the personal dive computer when there is the least amount of tidal current.
3) equipment manufacturers made improvements _______ tide is when there is no horizontal water
to the design and workmanship of gear movement. - -Slack tide
Name 3 different devices that modern dive If you are caught in a rip current, first swim _____
computers replace - -1) dive tables to the current to get out of it before swimming
2) J-valves towards shore. - -Parallel
3) depth gauges
Waves are usually caused by - -Wind
What sets SDI apart from other training pushing water on the surface
agencies? - -First dive training agency to
provide entry level scuba instruction that
incorporates the use of personal dive computers
--> more streamlined scuba course w/ more T or F: Anticipate surge action to avoid contact
instruction time in the water with stationary objects - -True
How much larger and closer do objects appear What type of marine life cause most diving
underwater and why? - -Objects injuries? - -Most diving injuries result from
underwater appear 25% larger and 25% closer animal's defensive response to a perceived threat
As light travels through the airspace created by
the mask, it bends, creating a magnifying effect.
What should you do if you see a potentially
dangerous animal underwater and it does not
leave the area? - -Remain still and calm.
How much faster does sound move through Slowly leave area if necessary.
water than air and why? - -4 times faster
1/8
, SDI Scuba Certification Exam Study Guide with Verified
Answers Graded A+
in your ears upon descending? - -Stop,
ascend a few feet until you no longer feel
List three different reasons that it is advisable to discomfort, equalize again, then continue with
check with your local dive center before descent
conducting a dive in an area you are unfamiliar
with? - -1) tidal conditions
2) marine life
3) first aid for potential injuries in area What is a reverse block? - -When air
cannot escape freely from an air space during
ascent
What is the absolute pressure (in atm/bar) at 20 causes pain and discomfort in the ears and
meters (66 feet)? - -3 atm/bar sinuses
What will be the volume in a ball that is filled with What should you do if you experience a reverse
2 cubic feet/liters of air at 30 meters (90 feet) block upon ascending? - -Stop, descend a
when it is taken to surface? - -8 cubic few feet until pain subsides, wait to allow air to
feet/liter (4x the volume) vent, then continue with ascent
How many more times dense is the air in a ballon What is the most important rule in scuba diving? -
at 4 atm/bar compared to air density at surface? - -Breathe continuously and never hold your
-4x breath
If a scuba cylinder lasts two hours at sea level, What is the most serious injury that a diver could
how long will it last at 20 m/66 ft? - -40 suffer from if they hold their breath upon
minutes ascending? - -Lung over-expansion
120 min x 1/3 (vol) = 40 min
Which gas component in air causes
decompression sickness and narcosis? - -
How often should a scuba diver equalize during Nitrogen
descent? - -At the surface before descent
and every couple of feet
What medical problem can occur if a diver
ascends much too rapidly for nitrogen to be
What should you do if you experience discomfort slowly released? - -Decompression
2/8
