PADI Open Water Diver Final Exam 2026 -
Complete Study Guide with Questions,
Correct Answers and Detailed Rationales |
Latest Update -Graded A+
Question 1
If an object is neutrally buoyant (does not sink or float) in fresh water, the same object
placed into salt water would
A. Sink
B. Either sink or float
C. Do nothing
D. Float
Correct Answer: D
Rationale: Salt water is heavier than fresh water because it has dissolved minerals in
it. This means it causes more upward force (buoyancy) on an object. An object that is
neutrally buoyant in fresh water would float in salt water because there is greater
upward force.
See Being a Diver I - Buoyancy and Controlling Buoyancy.
Question 2
I blow up a balloon, tie it off, and take it to the bottom of the swimming pool. What will
happen to the balloon and the air inside it?
A. The balloon will get bigger and the air inside the balloon will be less dense (molecules
move further apart).
B. The balloon will get smaller and the air inside the balloon will be more dense
(molecules move closer together).
C. The balloon will get bigger and the air inside the balloon will be more dense.
D. The balloon will get smaller and the air inside the balloon will be less dense.
Correct Answer: B
pg. 1
,Rationale: As water pressure increases, the volume of an air space will decrease. This
causes the density of the air inside to increase and air molecules are pushed closer
together. The balloon would get smaller and the air density inside would be greater.
See Being a Diver I - Water Pressure and Air Volume Effects.
Question 3
I turn a glass upside down, trap the air in it by putting it in water, and then I take the
glass down to 10 meters. The air space would
A. Become half the size it was at the surface.
B. Not change in size.
C. Become 1/3 the size it was at the surface.
D. Become 2/3 the size it was at the surface.
Correct Answer: A
Rationale: At 10 meters, the pressure is 2 bar (1 atm at surface + 1 atm from water). An
air volume taken to this depth from the surface would decrease and become half the
size. This follows Boyle's Law: volume is inversely proportional to pressure.
See Being a Diver I - Water Pressure and Air Volume Effects.
Question 4
If I am not able to equalize (clear) my body air spaces, it may be because I have
A. Seasickness.
B. Heart disease and high blood pressure.
C. A cold, allergy or another medical problem.
D. Anxiety.
Correct Answer: C
Rationale: A cold, or any congestion, can block air passages in your ears and sinuses,
making equalization difficult or impossible. Seasickness, heart disease, high blood
pressure, and anxiety are not direct causes of equalization problems.
See Being a Diver I - The Effects of Increasing Pressure on Body Air Spaces.
Question 5
If my ears or sinuses hurt while I am descending (going down), it usually means
pg. 2
, A. My air spaces are equalized.
B. My mask strap is too tight.
C. I am feeling a squeeze and need to equalize.
D. My mask is too small.
Correct Answer: C
Rationale: Pain in your ears or sinuses means that they aren't equalized. Stop your
descent and ascend slightly to relieve pressure on your ears. Then attempt to equalize
again. If you can't equalize, end the dive.
See Being a Diver I - The Effects of Increasing Pressure on Body Air Spaces.
Question 6
The best place for me to position an alternate air source is
A. Loose by my side so I can find it fast.
B. In the triangle area formed by my chin and the lower corners of my rib cage.
C. To the base of my cylinder.
D. To the back of my BCD between my shoulder blades and waist.
Correct Answer: B
Rationale: Your alternate air source attaches with a quick release in the triangle area
formed by your chin and the lower corners of your rib cage. Avoid letting your alternate
air source dangle unsecured from your kit.
See Equipment I - Regulators.
Question 7
Lung overexpansion injuries can be caused by
A. Scuba diving without a buddy.
B. Continuing a dive when not properly weighted.
C. Not drinking enough water before scuba diving.
D. Holding my breath while scuba diving.
Correct Answer: D
Rationale: Blocking off your lungs by holding your breath and ascending could cause
them to overexpand and rupture, which is a serious injury that could result in paralysis
and death. Breathing continuously while scuba diving keeps air passages open allowing
expanding air to escape.
pg. 3
Complete Study Guide with Questions,
Correct Answers and Detailed Rationales |
Latest Update -Graded A+
Question 1
If an object is neutrally buoyant (does not sink or float) in fresh water, the same object
placed into salt water would
A. Sink
B. Either sink or float
C. Do nothing
D. Float
Correct Answer: D
Rationale: Salt water is heavier than fresh water because it has dissolved minerals in
it. This means it causes more upward force (buoyancy) on an object. An object that is
neutrally buoyant in fresh water would float in salt water because there is greater
upward force.
See Being a Diver I - Buoyancy and Controlling Buoyancy.
Question 2
I blow up a balloon, tie it off, and take it to the bottom of the swimming pool. What will
happen to the balloon and the air inside it?
A. The balloon will get bigger and the air inside the balloon will be less dense (molecules
move further apart).
B. The balloon will get smaller and the air inside the balloon will be more dense
(molecules move closer together).
C. The balloon will get bigger and the air inside the balloon will be more dense.
D. The balloon will get smaller and the air inside the balloon will be less dense.
Correct Answer: B
pg. 1
,Rationale: As water pressure increases, the volume of an air space will decrease. This
causes the density of the air inside to increase and air molecules are pushed closer
together. The balloon would get smaller and the air density inside would be greater.
See Being a Diver I - Water Pressure and Air Volume Effects.
Question 3
I turn a glass upside down, trap the air in it by putting it in water, and then I take the
glass down to 10 meters. The air space would
A. Become half the size it was at the surface.
B. Not change in size.
C. Become 1/3 the size it was at the surface.
D. Become 2/3 the size it was at the surface.
Correct Answer: A
Rationale: At 10 meters, the pressure is 2 bar (1 atm at surface + 1 atm from water). An
air volume taken to this depth from the surface would decrease and become half the
size. This follows Boyle's Law: volume is inversely proportional to pressure.
See Being a Diver I - Water Pressure and Air Volume Effects.
Question 4
If I am not able to equalize (clear) my body air spaces, it may be because I have
A. Seasickness.
B. Heart disease and high blood pressure.
C. A cold, allergy or another medical problem.
D. Anxiety.
Correct Answer: C
Rationale: A cold, or any congestion, can block air passages in your ears and sinuses,
making equalization difficult or impossible. Seasickness, heart disease, high blood
pressure, and anxiety are not direct causes of equalization problems.
See Being a Diver I - The Effects of Increasing Pressure on Body Air Spaces.
Question 5
If my ears or sinuses hurt while I am descending (going down), it usually means
pg. 2
, A. My air spaces are equalized.
B. My mask strap is too tight.
C. I am feeling a squeeze and need to equalize.
D. My mask is too small.
Correct Answer: C
Rationale: Pain in your ears or sinuses means that they aren't equalized. Stop your
descent and ascend slightly to relieve pressure on your ears. Then attempt to equalize
again. If you can't equalize, end the dive.
See Being a Diver I - The Effects of Increasing Pressure on Body Air Spaces.
Question 6
The best place for me to position an alternate air source is
A. Loose by my side so I can find it fast.
B. In the triangle area formed by my chin and the lower corners of my rib cage.
C. To the base of my cylinder.
D. To the back of my BCD between my shoulder blades and waist.
Correct Answer: B
Rationale: Your alternate air source attaches with a quick release in the triangle area
formed by your chin and the lower corners of your rib cage. Avoid letting your alternate
air source dangle unsecured from your kit.
See Equipment I - Regulators.
Question 7
Lung overexpansion injuries can be caused by
A. Scuba diving without a buddy.
B. Continuing a dive when not properly weighted.
C. Not drinking enough water before scuba diving.
D. Holding my breath while scuba diving.
Correct Answer: D
Rationale: Blocking off your lungs by holding your breath and ascending could cause
them to overexpand and rupture, which is a serious injury that could result in paralysis
and death. Breathing continuously while scuba diving keeps air passages open allowing
expanding air to escape.
pg. 3
