SDI Final Exam Questions and Answers
(2026) | Comprehensive Solutions with
Step-by-Step Rationales | A+ Verified
• What happens to colors under water -✓✓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: -✓✓Sound's increases speed under
water makes it harder to determine the direction from which it is coming.
• Water conducts heat away from your body ___ times faster than air does -✓✓25
• The presence of thermoclines means that -✓✓divers may require more in the way
of exposure protection at depth than they will at the surface.
• Tides can: -✓✓- make water seem deeper or shallower, stronger and difficult,
adverse effect on visibility
• Cause of permanent ocean currents -✓✓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 -✓✓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 -✓✓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 -✓✓Surge is the back-and-forth movement of water caused by
waves passing over head.
• What causes most aquatic animal bites? -✓✓An animal's defensive response to a
perceived threat & mistaken identity
• To be injured by an animal with poisonous spines, you must: -✓✓Be the
aggressor and touch the animal first.
,• The states of buoyancy include all of the following except: -✓✓Passive
• If you feel pain or discomfort during descent: -✓✓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? -
✓✓
• Any time you cannot inhale while scuba diving (such as when a regulator is out
of your mouth), you must be -✓✓Exhaling.
• What can help prevent decompression sickness (DCS) -✓✓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: -✓✓Rapid ascents,
'Pushing" or exceeding your computer's no-decompression limits, Heavy exertion
and/or dehydration.
• best way to prevent or reduce nitrogen narcosis? -✓✓Avoid dives below 20
meters/66 feet.
• Which of the following may indicate that air in a scuba cylinder is contaminated
and potentially toxic? -✓✓color, odor, taste
• Desirable mask features include -✓✓1: Soft, silicone skirt.
2: Low internal volume.
3: Snug, comfortable fit.
• The types of fins commonly used by recreational scuba divers include -✓✓full
foot and open heel
• Basic post-dive equipment maintenance and care includes -✓✓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 -✓✓1: Dive skins.
2: Wet suits.
3: Dry suits.
• Your body loses the greatest amount of heat through the -✓✓Head.
• Which of the following is/are important features of a weight system? -✓✓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 -✓✓Jacket-style (wraparound), Back-inflation style
• A regulator system may include -✓✓1: A first stage and primary second stage.
2: An alternate air source second stage (or a connection to an alternate-air-source
inflator on the BC).
3: A submersible pressure gauge (SPG), which is usually part of an instrument
console.
• A regulator equipped with a conventional alternate-air-source second stage: -
✓✓Conventional alternate-air-source second stages offer the benefit of being
widely understood and used, and enable either diver to use either second stage.
• Scuba cylinders must periodically undergo: -✓✓visual inspections and
hydrostatic tests, at intervals determined by local laws and regulations, or
prevailing standards of practice.
• The minimum information most dive computers provide you with while in Dive
mode include: -✓✓1: Current and maximum dive depth.
2: Actual bottom time.
3: Decompression status (no-deco limit or required deco).
• A dive knife or cutting tool can be used to -✓✓help free entangled divers or
signal others under water.
• Steps in equipment assembly include all of the following except -✓✓You want to
pressurize (not depressurize) your regulator and then test each second stage.
, • What piece of equipment should never be allowed to dangle freely? -✓✓Your
alternate-air-source second stage and submersible pressure gauge or instrument
console should never be allowed to dangle freely. (It would be nice to clip off the
BC power inflator as well, but that is not possible.)
• After your buddy checks to see that your air is turned all the way on: -✓✓take
several deep breaths from your regulator while watching your SPG for changes in
pressure.
• Which is the most common boat entry technique for deep water entry on large
dive boats? -✓✓A giant stride is the most common boat entry technique.
• The preferred way to remove moisture from a dust cap prior to putting it back in
place is to: -✓✓The preferred way to remove moisture from a dust cap prior to
putting it back in place is to wipe it with a clean, dry towel or cloth.
• Air passages such as your trachea (windpipe), which may contain air your body
can't use, are known as: -✓✓Dead air spaces.
• Common methods for clearing water from a regulator second stage include: -
✓✓exhaling into the second stage and depressing the purge button.
• The two most common methods for recovering a regulator that has fallen behind
your shoulder are: -✓✓Reach, Sweep
• Contact lens wearers should not close their eyes when clearing a mask. -✓✓It is
important that contact lens wearers close their eyes when performing this skill, to
help prevent accidental lens loss.
• The key to venting a BC, at the surface or under water, is to: -✓✓turn your body
so the the exhaust valve is the highest point on the BC air cell.
• Before adding air to your BC under water, you must: -✓✓You need to continue
to breathe normally while adding air to your BC.
• The three As of buoyancy control include -✓✓1: Awareness.
2: Anticipation.
3. Action.
(2026) | Comprehensive Solutions with
Step-by-Step Rationales | A+ Verified
• What happens to colors under water -✓✓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: -✓✓Sound's increases speed under
water makes it harder to determine the direction from which it is coming.
• Water conducts heat away from your body ___ times faster than air does -✓✓25
• The presence of thermoclines means that -✓✓divers may require more in the way
of exposure protection at depth than they will at the surface.
• Tides can: -✓✓- make water seem deeper or shallower, stronger and difficult,
adverse effect on visibility
• Cause of permanent ocean currents -✓✓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 -✓✓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 -✓✓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 -✓✓Surge is the back-and-forth movement of water caused by
waves passing over head.
• What causes most aquatic animal bites? -✓✓An animal's defensive response to a
perceived threat & mistaken identity
• To be injured by an animal with poisonous spines, you must: -✓✓Be the
aggressor and touch the animal first.
,• The states of buoyancy include all of the following except: -✓✓Passive
• If you feel pain or discomfort during descent: -✓✓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? -
✓✓
• Any time you cannot inhale while scuba diving (such as when a regulator is out
of your mouth), you must be -✓✓Exhaling.
• What can help prevent decompression sickness (DCS) -✓✓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: -✓✓Rapid ascents,
'Pushing" or exceeding your computer's no-decompression limits, Heavy exertion
and/or dehydration.
• best way to prevent or reduce nitrogen narcosis? -✓✓Avoid dives below 20
meters/66 feet.
• Which of the following may indicate that air in a scuba cylinder is contaminated
and potentially toxic? -✓✓color, odor, taste
• Desirable mask features include -✓✓1: Soft, silicone skirt.
2: Low internal volume.
3: Snug, comfortable fit.
• The types of fins commonly used by recreational scuba divers include -✓✓full
foot and open heel
• Basic post-dive equipment maintenance and care includes -✓✓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 -✓✓1: Dive skins.
2: Wet suits.
3: Dry suits.
• Your body loses the greatest amount of heat through the -✓✓Head.
• Which of the following is/are important features of a weight system? -✓✓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 -✓✓Jacket-style (wraparound), Back-inflation style
• A regulator system may include -✓✓1: A first stage and primary second stage.
2: An alternate air source second stage (or a connection to an alternate-air-source
inflator on the BC).
3: A submersible pressure gauge (SPG), which is usually part of an instrument
console.
• A regulator equipped with a conventional alternate-air-source second stage: -
✓✓Conventional alternate-air-source second stages offer the benefit of being
widely understood and used, and enable either diver to use either second stage.
• Scuba cylinders must periodically undergo: -✓✓visual inspections and
hydrostatic tests, at intervals determined by local laws and regulations, or
prevailing standards of practice.
• The minimum information most dive computers provide you with while in Dive
mode include: -✓✓1: Current and maximum dive depth.
2: Actual bottom time.
3: Decompression status (no-deco limit or required deco).
• A dive knife or cutting tool can be used to -✓✓help free entangled divers or
signal others under water.
• Steps in equipment assembly include all of the following except -✓✓You want to
pressurize (not depressurize) your regulator and then test each second stage.
, • What piece of equipment should never be allowed to dangle freely? -✓✓Your
alternate-air-source second stage and submersible pressure gauge or instrument
console should never be allowed to dangle freely. (It would be nice to clip off the
BC power inflator as well, but that is not possible.)
• After your buddy checks to see that your air is turned all the way on: -✓✓take
several deep breaths from your regulator while watching your SPG for changes in
pressure.
• Which is the most common boat entry technique for deep water entry on large
dive boats? -✓✓A giant stride is the most common boat entry technique.
• The preferred way to remove moisture from a dust cap prior to putting it back in
place is to: -✓✓The preferred way to remove moisture from a dust cap prior to
putting it back in place is to wipe it with a clean, dry towel or cloth.
• Air passages such as your trachea (windpipe), which may contain air your body
can't use, are known as: -✓✓Dead air spaces.
• Common methods for clearing water from a regulator second stage include: -
✓✓exhaling into the second stage and depressing the purge button.
• The two most common methods for recovering a regulator that has fallen behind
your shoulder are: -✓✓Reach, Sweep
• Contact lens wearers should not close their eyes when clearing a mask. -✓✓It is
important that contact lens wearers close their eyes when performing this skill, to
help prevent accidental lens loss.
• The key to venting a BC, at the surface or under water, is to: -✓✓turn your body
so the the exhaust valve is the highest point on the BC air cell.
• Before adding air to your BC under water, you must: -✓✓You need to continue
to breathe normally while adding air to your BC.
• The three As of buoyancy control include -✓✓1: Awareness.
2: Anticipation.
3. Action.
