SDI Open Water Scuba Diver Exam
UPDATED Exam Questions and CORRECT
Answers
How does the size and distance of objects under water differ from their appearance in air? -
CORRECT ANSWER - Water is denser than air, therefore both light and sound travel
differently under water than they do on the surface.
Refraction - CORRECT 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? - CORRECT 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? - CORRECT 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? - CORRECT 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 - CORRECT 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?
- CORRECT ANSWER - -Water is approximately 800x denser than air, which allows it to
conduct sounds both further and faster than air.
UPDATED Exam Questions and CORRECT
Answers
How does the size and distance of objects under water differ from their appearance in air? -
CORRECT ANSWER - Water is denser than air, therefore both light and sound travel
differently under water than they do on the surface.
Refraction - CORRECT 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? - CORRECT 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? - CORRECT 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? - CORRECT 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 - CORRECT 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?
- CORRECT ANSWER - -Water is approximately 800x denser than air, which allows it to
conduct sounds both further and faster than air.
