SDI Exam Questions with 100% Correct
Answers Updated 2026
Water conducts heat away from your body ___ times faster than air does - ANSWER-25
The presence of thermoclines means that - ANSWER-divers may require more in the
way of exposure protection at depth than they will at the surface.
Tides can: - ANSWER-- make water seem deeper or shallower, stronger and difficult,
adverse effect on visibility
Cause of permanent ocean currents - ANSWER-The sun warming water near the
equator, coupled with the earth's rotation, is the primary cause of permanent ocean
currents.
Wave height and length - ANSWER-Wave height is the distance from its highest point
(crest) to its lowest point (trough). Wave length is the distance from crest to crest.
formation of surf - ANSWER-A wave encountering shallow water begins to slow at its
bottom, while the top of the wave continues at its previous speed. This causes the wave
to break.
what is surge - ANSWER-Surge is the back-and-forth movement of water caused by
waves passing over head.
What causes most aquatic animal bites? - ANSWER-An animal's defensive response to
a perceived threat & mistaken identity
To be injured by an animal with poisonous spines, you must: - ANSWER-Be the
aggressor and touch the animal first.
The states of buoyancy include all of the following except: - ANSWER-Passive
If you feel pain or discomfort during descent: - ANSWER-Ascend to the point where you
can comfortably equalize, and only then continue your descent.
Which of the following is the best way to prevent or reduce nitrogen narcosis? -
ANSWER-
Objects under water appear: - ANSWER-Closer and larger than they do on land
What happens to colors under water - ANSWER-As you descend, colors appear to
fade, not intensify. Blues and grays are the last remaining colors at depth.
, Because sound travels faster under water: - ANSWER-Sound's increases speed under
water makes it harder to determine the direction from which it is coming.
Any time you cannot inhale while scuba diving (such as when a regulator is out of your
mouth), you must be - ANSWER-Exhaling.
What can help prevent decompression sickness (DCS) - ANSWER-safety stops,
Remain well within your dive computer's no-decompression limit, Ascend no faster than
the rate allowed by the dive computer
Contributing factors to decompression sickness can include: - ANSWER-Rapid ascents,
'Pushing" or exceeding your computer's no-decompression limits, Heavy exertion and/or
dehydration.
best way to prevent or reduce nitrogen narcosis? - ANSWER-Avoid dives below 20
meters/66 feet.
Which of the following may indicate that air in a scuba cylinder is contaminated and
potentially toxic? - ANSWER-color, odor, taste
Desirable mask features include - ANSWER-1: Soft, silicone skirt.
2: Low internal volume.
3: Snug, comfortable fit.
The types of fins commonly used by recreational scuba divers include - ANSWER-full
foot and open heel
Basic post-dive equipment maintenance and care includes - ANSWER-1: Rinsing
thoroughly with fresh water.
2: Allowing to dry completely.
3: Storing in a cool, dry place, away from direct sunlight.
Common exposure suit types include - ANSWER-1: Dive skins.
2: Wet suits.
3: Dry suits.
Your body loses the greatest amount of heat through the - ANSWER-Head.
Which of the following is/are important features of a weight system? - ANSWER-There
is no established minimum capacity for a weight system. So long as it has a quick-
release mechanism and is easy to adjust the amount of weight used, any system that
enables you to carry enough ballast to be properly weighted is fine.
Popular BC styles include - ANSWER-Jacket-style (wraparound), Back-inflation style
A regulator system may include - ANSWER-1: A first stage and primary second stage.
Answers Updated 2026
Water conducts heat away from your body ___ times faster than air does - ANSWER-25
The presence of thermoclines means that - ANSWER-divers may require more in the
way of exposure protection at depth than they will at the surface.
Tides can: - ANSWER-- make water seem deeper or shallower, stronger and difficult,
adverse effect on visibility
Cause of permanent ocean currents - ANSWER-The sun warming water near the
equator, coupled with the earth's rotation, is the primary cause of permanent ocean
currents.
Wave height and length - ANSWER-Wave height is the distance from its highest point
(crest) to its lowest point (trough). Wave length is the distance from crest to crest.
formation of surf - ANSWER-A wave encountering shallow water begins to slow at its
bottom, while the top of the wave continues at its previous speed. This causes the wave
to break.
what is surge - ANSWER-Surge is the back-and-forth movement of water caused by
waves passing over head.
What causes most aquatic animal bites? - ANSWER-An animal's defensive response to
a perceived threat & mistaken identity
To be injured by an animal with poisonous spines, you must: - ANSWER-Be the
aggressor and touch the animal first.
The states of buoyancy include all of the following except: - ANSWER-Passive
If you feel pain or discomfort during descent: - ANSWER-Ascend to the point where you
can comfortably equalize, and only then continue your descent.
Which of the following is the best way to prevent or reduce nitrogen narcosis? -
ANSWER-
Objects under water appear: - ANSWER-Closer and larger than they do on land
What happens to colors under water - ANSWER-As you descend, colors appear to
fade, not intensify. Blues and grays are the last remaining colors at depth.
, Because sound travels faster under water: - ANSWER-Sound's increases speed under
water makes it harder to determine the direction from which it is coming.
Any time you cannot inhale while scuba diving (such as when a regulator is out of your
mouth), you must be - ANSWER-Exhaling.
What can help prevent decompression sickness (DCS) - ANSWER-safety stops,
Remain well within your dive computer's no-decompression limit, Ascend no faster than
the rate allowed by the dive computer
Contributing factors to decompression sickness can include: - ANSWER-Rapid ascents,
'Pushing" or exceeding your computer's no-decompression limits, Heavy exertion and/or
dehydration.
best way to prevent or reduce nitrogen narcosis? - ANSWER-Avoid dives below 20
meters/66 feet.
Which of the following may indicate that air in a scuba cylinder is contaminated and
potentially toxic? - ANSWER-color, odor, taste
Desirable mask features include - ANSWER-1: Soft, silicone skirt.
2: Low internal volume.
3: Snug, comfortable fit.
The types of fins commonly used by recreational scuba divers include - ANSWER-full
foot and open heel
Basic post-dive equipment maintenance and care includes - ANSWER-1: Rinsing
thoroughly with fresh water.
2: Allowing to dry completely.
3: Storing in a cool, dry place, away from direct sunlight.
Common exposure suit types include - ANSWER-1: Dive skins.
2: Wet suits.
3: Dry suits.
Your body loses the greatest amount of heat through the - ANSWER-Head.
Which of the following is/are important features of a weight system? - ANSWER-There
is no established minimum capacity for a weight system. So long as it has a quick-
release mechanism and is easy to adjust the amount of weight used, any system that
enables you to carry enough ballast to be properly weighted is fine.
Popular BC styles include - ANSWER-Jacket-style (wraparound), Back-inflation style
A regulator system may include - ANSWER-1: A first stage and primary second stage.
