1 | P a g e | © copyright 2024/2025 | Grade A+
SDI Certification Exam Review
Questions and Answers | Latest
Update 2024/2025
What does SCUBA stand for?
✓ ~~> Self
✓ Contained
✓ Underwater
✓ Breathing
✓ Apparatus
List the three important scuba diving changes that occurred in the 1950s
✓ ~~> 1) Dive tables published for repetitive dives
✓ 2) Improved design/quality of scuba gear
✓ 3) Dive computers commercially available
Name three different devices that modern dive computers replace
✓ ~~> Depth gauge, dive tables, watch
What sets SDI apart from other training agencies?
✓ ~~> Students use a personal dive computer for all instruction and
certification dives
Master01 | September, 2024/2025 | Latest update
, 2 | P a g e | © copyright 2024/2025 | Grade A+
How much larger and closer do objects appear under water and why?
✓ ~~> 33% larger, 25% closer
Light bends in the air-space between the lens and your eyes.
How much faster does sound move through water than air and why?
✓ ~~> 4 times faster in water
Water is 800x denser than air; sound travels through denser mediums at faster
rates
What is the first color absorbed underwater?
✓ ~~> RED (followed by OYGBIV)
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
If you are caught in a rip current, first swim _____ to the current to get out of it
before swimming towards shore.
✓ ~~> Perpendicular
Start your dive by swimming ____ the current
Master01 | September, 2024/2025 | Latest update
SDI Certification Exam Review
Questions and Answers | Latest
Update 2024/2025
What does SCUBA stand for?
✓ ~~> Self
✓ Contained
✓ Underwater
✓ Breathing
✓ Apparatus
List the three important scuba diving changes that occurred in the 1950s
✓ ~~> 1) Dive tables published for repetitive dives
✓ 2) Improved design/quality of scuba gear
✓ 3) Dive computers commercially available
Name three different devices that modern dive computers replace
✓ ~~> Depth gauge, dive tables, watch
What sets SDI apart from other training agencies?
✓ ~~> Students use a personal dive computer for all instruction and
certification dives
Master01 | September, 2024/2025 | Latest update
, 2 | P a g e | © copyright 2024/2025 | Grade A+
How much larger and closer do objects appear under water and why?
✓ ~~> 33% larger, 25% closer
Light bends in the air-space between the lens and your eyes.
How much faster does sound move through water than air and why?
✓ ~~> 4 times faster in water
Water is 800x denser than air; sound travels through denser mediums at faster
rates
What is the first color absorbed underwater?
✓ ~~> RED (followed by OYGBIV)
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
If you are caught in a rip current, first swim _____ to the current to get out of it
before swimming towards shore.
✓ ~~> Perpendicular
Start your dive by swimming ____ the current
Master01 | September, 2024/2025 | Latest update
