1 | P a g e | © copyright 2024/2025 | Grade A+
SDI Scuba Certification Exam Study
Guide Questions and Answers | Latest
Update 2024/2025
Define SCUBA
✓ ~~> S - self
C - contained
U - underwater
B - breathing
A - apparatus
List 3 important scuba diving changes that occurred in 1950s
✓ ~~> 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
✓ ~~> 1) dive tables
2) J-valves
3) depth gauges
What sets SDI apart from other training agencies?
Master01 | September, 2024/2025 | Latest update
, 2 | P a g e | © copyright 2024/2025 | Grade A+
✓ ~~> 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?
✓ ~~> 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?
✓ ~~> 4 times faster because water is about 800 times denser than air.
What is the first color to be absorbed underwater?
✓ ~~> 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.
✓ ~~> Slack tide
If you are caught in a rip current, first swim _____ to the current to get out of it
before swimming towards shore.
Master01 | September, 2024/2025 | Latest update
, 3 | P a g e | © copyright 2024/2025 | Grade A+
✓ ~~> Parallel
Waves are usually caused by
✓ ~~> Wind pushing water on the surface
T or F: Anticipate surge action to avoid contact with stationary objects
✓ ~~> True
What type of marine life cause most diving injuries?
✓ ~~> 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?
✓ ~~> 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?
✓ ~~> 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)?
Master01 | September, 2024/2025 | Latest update
SDI Scuba Certification Exam Study
Guide Questions and Answers | Latest
Update 2024/2025
Define SCUBA
✓ ~~> S - self
C - contained
U - underwater
B - breathing
A - apparatus
List 3 important scuba diving changes that occurred in 1950s
✓ ~~> 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
✓ ~~> 1) dive tables
2) J-valves
3) depth gauges
What sets SDI apart from other training agencies?
Master01 | September, 2024/2025 | Latest update
, 2 | P a g e | © copyright 2024/2025 | Grade A+
✓ ~~> 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?
✓ ~~> 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?
✓ ~~> 4 times faster because water is about 800 times denser than air.
What is the first color to be absorbed underwater?
✓ ~~> 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.
✓ ~~> Slack tide
If you are caught in a rip current, first swim _____ to the current to get out of it
before swimming towards shore.
Master01 | September, 2024/2025 | Latest update
, 3 | P a g e | © copyright 2024/2025 | Grade A+
✓ ~~> Parallel
Waves are usually caused by
✓ ~~> Wind pushing water on the surface
T or F: Anticipate surge action to avoid contact with stationary objects
✓ ~~> True
What type of marine life cause most diving injuries?
✓ ~~> 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?
✓ ~~> 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?
✓ ~~> 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)?
Master01 | September, 2024/2025 | Latest update
