SSI SCIENCE OF DIVING 2026/2027 STUDY GUIDE –
QUESTIONS AND ANSWERS RATED A+ – COMPLETE EXAM
PREP.
◎ If the volume of a gas is kept constant, what varies directly with temperature?
The pressure
All answers are correct
The mixing
The volume. 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%. 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. 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. 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. 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. 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. 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. 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. 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. 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. ANSWER: - Your positive buoyancy will increase
◎ For every foot of depth in freshwater, pressure changes by:
0.432 psi
0.147 psi
0.445 psi
0.864 psi. ANSWER: - 0.432 psi
◎ A diver and their equipment weighs 175 lbs. and is neutrally buoyant in saltwater. To
be neutrally buoyant in freshwater, diving with the same equipment, they must:
Remove weight
QUESTIONS AND ANSWERS RATED A+ – COMPLETE EXAM
PREP.
◎ If the volume of a gas is kept constant, what varies directly with temperature?
The pressure
All answers are correct
The mixing
The volume. 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%. 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. 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. 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. 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. 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. 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. 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. 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. 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. ANSWER: - Your positive buoyancy will increase
◎ For every foot of depth in freshwater, pressure changes by:
0.432 psi
0.147 psi
0.445 psi
0.864 psi. ANSWER: - 0.432 psi
◎ A diver and their equipment weighs 175 lbs. and is neutrally buoyant in saltwater. To
be neutrally buoyant in freshwater, diving with the same equipment, they must:
Remove weight
