1 | P a g e | © copyright 2024/2025 | Grade A+
SDI Scuba Certification Exam Study
Guide Questions and Answers (100%
Pass)
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 com puter
→ 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
Master01 | September, 2024/2025 | Latest update
, 1 | P a g e | © copyright 2024/2025 | Grade A+
→ 3) depth gauges
What sets SDI apart from other training 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
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?
Master01 | September, 2024/2025 | Latest update
, 1 | P a g e | © copyright 2024/2025 | Grade A+
→ 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.
→ 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?
Master01 | September, 2024/2025 | Latest update
SDI Scuba Certification Exam Study
Guide Questions and Answers (100%
Pass)
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 com puter
→ 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
Master01 | September, 2024/2025 | Latest update
, 1 | P a g e | © copyright 2024/2025 | Grade A+
→ 3) depth gauges
What sets SDI apart from other training 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
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?
Master01 | September, 2024/2025 | Latest update
, 1 | P a g e | © copyright 2024/2025 | Grade A+
→ 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.
→ 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?
Master01 | September, 2024/2025 | Latest update
