SDI OPEN WATER SCUBA DIVER ACTUAL
EXAM 2026 QUESTIONS WITH ANSWERS
GRADED A+
◉Refraction Answer: A magnifying effect created as light passes from
the water through the mask lens and BENDING into the space inside.
◉Why are dive mask needed to be worn from a visual aspect? Answer:
To focus under water, our eyes require an air space in front of them, just
as they do on land.
◉How much closer and larger do items appear under water? Answer:
Underwater, objects appear 25% closer and 1/3 larger than they do on
land.
◉How does depth affect the appearance of colors under water? Answer:
-As light passes through water, the water absorbs much of its color.
-Reds are the first to disappear, followed by oranges, yellows, greens,
and other colors of the spectrum.
-At a depth of 30m/99ft, little color remains other than blues, grays,
blacks, and whites.
**This is why divers often carry dive lights with them, even during day
operations.
, ◉Turbidity Answer: A measure of how clear water is. Often measured
by suspended particles in a measured amount of water. These particles
not only reduce visibility, but can also affect color underwater.
◉How does the speed with which sound travels under water compare to
the speed of sound in air? Answer: -Water is approximately 800x
denser than air, which allows it to conduct sounds both further and faster
than air.
-Sound waves move approximately 4x faster in water than in air.
◉How does the speed with which sound travels under water compare to
the speed of sound in air? Answer: -Above water, we are able to
determine a sound's direction between when a sound arrives at one ear
and when it arrives at the other.
-Under water, sounds arrive almost simultaneously at each ear, making it
difficult to sometimes determine the direction from which a sound is
coming.
◉Water conducts heat away from your body how many times faster than
air? Answer: About 25x faster than air does.
◉What is the abrupt change in temperature between layers of water?
Answer: -An abrupt change in water temperature is called a
Thermocline.
-Thermoclines can occur in any body of water.
EXAM 2026 QUESTIONS WITH ANSWERS
GRADED A+
◉Refraction Answer: A magnifying effect created as light passes from
the water through the mask lens and BENDING into the space inside.
◉Why are dive mask needed to be worn from a visual aspect? Answer:
To focus under water, our eyes require an air space in front of them, just
as they do on land.
◉How much closer and larger do items appear under water? Answer:
Underwater, objects appear 25% closer and 1/3 larger than they do on
land.
◉How does depth affect the appearance of colors under water? Answer:
-As light passes through water, the water absorbs much of its color.
-Reds are the first to disappear, followed by oranges, yellows, greens,
and other colors of the spectrum.
-At a depth of 30m/99ft, little color remains other than blues, grays,
blacks, and whites.
**This is why divers often carry dive lights with them, even during day
operations.
, ◉Turbidity Answer: A measure of how clear water is. Often measured
by suspended particles in a measured amount of water. These particles
not only reduce visibility, but can also affect color underwater.
◉How does the speed with which sound travels under water compare to
the speed of sound in air? Answer: -Water is approximately 800x
denser than air, which allows it to conduct sounds both further and faster
than air.
-Sound waves move approximately 4x faster in water than in air.
◉How does the speed with which sound travels under water compare to
the speed of sound in air? Answer: -Above water, we are able to
determine a sound's direction between when a sound arrives at one ear
and when it arrives at the other.
-Under water, sounds arrive almost simultaneously at each ear, making it
difficult to sometimes determine the direction from which a sound is
coming.
◉Water conducts heat away from your body how many times faster than
air? Answer: About 25x faster than air does.
◉What is the abrupt change in temperature between layers of water?
Answer: -An abrupt change in water temperature is called a
Thermocline.
-Thermoclines can occur in any body of water.
