SSI Science Of Diving 2025//2025
With questions and answers written
correctly
At an altitude of about 16,000 feet, the atmospheric pressure is approximately:
1/18th the atmospheric pressure at sea level
Equal to the atmospheric pressure at sea level
Twice the atmospheric pressure at sea level
One-half the atmospheric pressure at sea level - correct answer <<<✨✨✨One-half the atmospheric
pressure at sea level
If the volume of a gas is kept constant, what varies directly with temperature?
The pressure
All answers are correct
The mixing
The volume - correct answer <<<✨✨✨The pressure
Our perception of light changes as it travels from the water, through the glass of the mask, and into the
air pocket in front of the eyes. This gives a magnification factor of ____ to the objects we see
underwater.
None
50%
100%
33% - correct answer <<<✨✨✨33%
Sound travels differently in water than in air. The major difference is that it travels:
Approximately 4 times slower
,Approximately 10 times faster
Approximately 2 times faster
Approximately 4 times faster - correct answer <<<✨✨✨Approximately 4 times faster
The absolute pressure at a depth of 165 feet in salt water is:
5.012 ata
5.000 ata
6.000 ata
5.901 ata - correct answer <<<✨✨✨6.000 ata
The greatest expansion or compression per foot happens in which depth area?
66 to 33 ft
99 to 66 ft
First 33 ft
132 to 99 ft - correct answer <<<✨✨✨First 33 ft
Objects do not appear the same in the underwater environment as they do on land. Some major factors
that influence this difference in appearance are:
Refraction and Absorption only
Turbidity and Diffusion only
Absorption and Diffusion only
Refraction, Absorption, Diffusion and Turbidity - correct answer <<<✨✨✨Refraction, Absorption,
Diffusion and Turbidity
The absolute pressure at a depth of 132 feet in saltwater is:
5.000 ata
4.852 ata
4.084 ata
5.012 ata - correct answer <<<✨✨✨5.000 ata
, The ocean depth at which the partial pressure of oxygen in air equals 1.6 ata is _____ feet assuming O2
= 21%.
218
250
180
280 - correct answer <<<✨✨✨218
What is the surface air consumption rate (SAC) of a diver with a 3000psi-rated, 80-cubic foot cylinder,
using 650psi in 10 minutes, at a depth of 33 feet in the ocean?
34 psi/minute
28.5 psi/minute
30 psi/minute
32.5 psi/minute - correct answer <<<✨✨✨32.5 psi/minute
Breathing gas consumption:
Varies inversely with depth
Increases as depth increases
Remains the same as depth increases
Decreases as depth increases - correct answer <<<✨✨✨Increases as depth increases
If 0.10 cubic feet of air is needed in your buoyancy compensator to maintain neutral buoyancy at 30 feet
in the ocean, what will happen to your buoyancy if you ascend 10 feet without deflating?:
You will stay neutral, even if if you ascend or descend
Your positive buoyancy will increase
There will be no change in buoyancy
Your negative buoyancy will increase - correct answer <<<✨✨✨Your positive buoyancy will
increase
For every foot of depth in freshwater, pressure changes by:
With questions and answers written
correctly
At an altitude of about 16,000 feet, the atmospheric pressure is approximately:
1/18th the atmospheric pressure at sea level
Equal to the atmospheric pressure at sea level
Twice the atmospheric pressure at sea level
One-half the atmospheric pressure at sea level - correct answer <<<✨✨✨One-half the atmospheric
pressure at sea level
If the volume of a gas is kept constant, what varies directly with temperature?
The pressure
All answers are correct
The mixing
The volume - correct answer <<<✨✨✨The pressure
Our perception of light changes as it travels from the water, through the glass of the mask, and into the
air pocket in front of the eyes. This gives a magnification factor of ____ to the objects we see
underwater.
None
50%
100%
33% - correct answer <<<✨✨✨33%
Sound travels differently in water than in air. The major difference is that it travels:
Approximately 4 times slower
,Approximately 10 times faster
Approximately 2 times faster
Approximately 4 times faster - correct answer <<<✨✨✨Approximately 4 times faster
The absolute pressure at a depth of 165 feet in salt water is:
5.012 ata
5.000 ata
6.000 ata
5.901 ata - correct answer <<<✨✨✨6.000 ata
The greatest expansion or compression per foot happens in which depth area?
66 to 33 ft
99 to 66 ft
First 33 ft
132 to 99 ft - correct answer <<<✨✨✨First 33 ft
Objects do not appear the same in the underwater environment as they do on land. Some major factors
that influence this difference in appearance are:
Refraction and Absorption only
Turbidity and Diffusion only
Absorption and Diffusion only
Refraction, Absorption, Diffusion and Turbidity - correct answer <<<✨✨✨Refraction, Absorption,
Diffusion and Turbidity
The absolute pressure at a depth of 132 feet in saltwater is:
5.000 ata
4.852 ata
4.084 ata
5.012 ata - correct answer <<<✨✨✨5.000 ata
, The ocean depth at which the partial pressure of oxygen in air equals 1.6 ata is _____ feet assuming O2
= 21%.
218
250
180
280 - correct answer <<<✨✨✨218
What is the surface air consumption rate (SAC) of a diver with a 3000psi-rated, 80-cubic foot cylinder,
using 650psi in 10 minutes, at a depth of 33 feet in the ocean?
34 psi/minute
28.5 psi/minute
30 psi/minute
32.5 psi/minute - correct answer <<<✨✨✨32.5 psi/minute
Breathing gas consumption:
Varies inversely with depth
Increases as depth increases
Remains the same as depth increases
Decreases as depth increases - correct answer <<<✨✨✨Increases as depth increases
If 0.10 cubic feet of air is needed in your buoyancy compensator to maintain neutral buoyancy at 30 feet
in the ocean, what will happen to your buoyancy if you ascend 10 feet without deflating?:
You will stay neutral, even if if you ascend or descend
Your positive buoyancy will increase
There will be no change in buoyancy
Your negative buoyancy will increase - correct answer <<<✨✨✨Your positive buoyancy will
increase
For every foot of depth in freshwater, pressure changes by:
