SDI SCUBA CERTIFICATION EXAM STUDY GUIDE WITH CORRECT
ANSWERS | 100% VERIFIED|GRADED A+
Define SCUBA - (answers)S - self
C - contained
U - underwater
B - breathing
A - apparatus
List 3 important scuba diving changes that occurred in 1950s - (answers)1) published
USN dive tables
2) invented the personal dive computer
3) equipment manufacturers made improvements to the design and workmanship of
gear
Name 3 different devices that modern dive computers replace - (answers)1) dive tables
2) J-valves
3) depth gauges
What sets SDI apart from other training agencies? - (answers)First dive training agency
to provide entry level scuba instruction that incorporates the use of personal dive
computers --> more streamlined scuba course w/ more instruction time in the water
How much larger and closer do objects appear underwater and why? -
(answers)Objects underwater appear 25% larger and 25% closer
As light travels through the airspace created by the mask, it bends, creating a
magnifying effect.
How much faster does sound move through water than air and why? - (answers)4 times
faster because water is about 800 times denser than air.
What is the first color to be absorbed underwater? - (answers)Red (within first 25 feet)
When diving from shore, the best time to dive is when there is the least amount of tidal
current. _______ tide is when there is no horizontal water movement. - (answers)Slack
tide
If you are caught in a rip current, first swim _____ to the current to get out of it before
swimming towards shore. - (answers)Parallel
Waves are usually caused by - (answers)Wind pushing water on the surface
T or F: Anticipate surge action to avoid contact with stationary objects - (answers)True
, What type of marine life cause most diving injuries? - (answers)Most diving injuries
result from animal's defensive response to a perceived threat
What should you do if you see a potentially dangerous animal underwater and it does
not leave the area? - (answers)Remain still and calm. Slowly leave area if necessary.
List three different reasons that it is advisable to check with your local dive center before
conducting a dive in an area you are unfamiliar with? - (answers)1) tidal conditions
2) marine life
3) first aid for potential injuries in area
What is the absolute pressure (in atm/bar) at 20 meters (66 feet)? - (answers)3 atm/bar
What will be the volume in a ball that is filled with 2 cubic feet/liters of air at 30 meters
(90 feet) when it is taken to surface? - (answers)8 cubic feet/liter (4x the volume)
How many more times dense is the air in a ballon at 4 atm/bar compared to air density
at surface? - (answers)4x
If a scuba cylinder lasts two hours at sea level, how long will it last at 20 m/66 ft? -
(answers)40 minutes
120 min x 1/3 (vol) = 40 min
How often should a scuba diver equalize during descent? - (answers)At the surface
before descent and every couple of feet
What should you do if you experience discomfort in your ears upon descending? -
(answers)Stop, ascend a few feet until you no longer feel discomfort, equalize again,
then continue with descent
What is a reverse block? - (answers)When air cannot escape freely from an air space
during ascent
causes pain and discomfort in the ears and sinuses
What should you do if you experience a reverse block upon ascending? -
(answers)Stop, descend a few feet until pain subsides, wait to allow air to vent, then
continue with ascent
What is the most important rule in scuba diving? - (answers)Breathe continuously and
never hold your breath
What is the most serious injury that a diver could suffer from if they hold their breath
upon ascending? - (answers)Lung over-expansion
ANSWERS | 100% VERIFIED|GRADED A+
Define SCUBA - (answers)S - self
C - contained
U - underwater
B - breathing
A - apparatus
List 3 important scuba diving changes that occurred in 1950s - (answers)1) published
USN dive tables
2) invented the personal dive computer
3) equipment manufacturers made improvements to the design and workmanship of
gear
Name 3 different devices that modern dive computers replace - (answers)1) dive tables
2) J-valves
3) depth gauges
What sets SDI apart from other training agencies? - (answers)First dive training agency
to provide entry level scuba instruction that incorporates the use of personal dive
computers --> more streamlined scuba course w/ more instruction time in the water
How much larger and closer do objects appear underwater and why? -
(answers)Objects underwater appear 25% larger and 25% closer
As light travels through the airspace created by the mask, it bends, creating a
magnifying effect.
How much faster does sound move through water than air and why? - (answers)4 times
faster because water is about 800 times denser than air.
What is the first color to be absorbed underwater? - (answers)Red (within first 25 feet)
When diving from shore, the best time to dive is when there is the least amount of tidal
current. _______ tide is when there is no horizontal water movement. - (answers)Slack
tide
If you are caught in a rip current, first swim _____ to the current to get out of it before
swimming towards shore. - (answers)Parallel
Waves are usually caused by - (answers)Wind pushing water on the surface
T or F: Anticipate surge action to avoid contact with stationary objects - (answers)True
, What type of marine life cause most diving injuries? - (answers)Most diving injuries
result from animal's defensive response to a perceived threat
What should you do if you see a potentially dangerous animal underwater and it does
not leave the area? - (answers)Remain still and calm. Slowly leave area if necessary.
List three different reasons that it is advisable to check with your local dive center before
conducting a dive in an area you are unfamiliar with? - (answers)1) tidal conditions
2) marine life
3) first aid for potential injuries in area
What is the absolute pressure (in atm/bar) at 20 meters (66 feet)? - (answers)3 atm/bar
What will be the volume in a ball that is filled with 2 cubic feet/liters of air at 30 meters
(90 feet) when it is taken to surface? - (answers)8 cubic feet/liter (4x the volume)
How many more times dense is the air in a ballon at 4 atm/bar compared to air density
at surface? - (answers)4x
If a scuba cylinder lasts two hours at sea level, how long will it last at 20 m/66 ft? -
(answers)40 minutes
120 min x 1/3 (vol) = 40 min
How often should a scuba diver equalize during descent? - (answers)At the surface
before descent and every couple of feet
What should you do if you experience discomfort in your ears upon descending? -
(answers)Stop, ascend a few feet until you no longer feel discomfort, equalize again,
then continue with descent
What is a reverse block? - (answers)When air cannot escape freely from an air space
during ascent
causes pain and discomfort in the ears and sinuses
What should you do if you experience a reverse block upon ascending? -
(answers)Stop, descend a few feet until pain subsides, wait to allow air to vent, then
continue with ascent
What is the most important rule in scuba diving? - (answers)Breathe continuously and
never hold your breath
What is the most serious injury that a diver could suffer from if they hold their breath
upon ascending? - (answers)Lung over-expansion
