2025 PADI OPEN WATER DIVER CERTIFICATION EXAM QUESTIONS AND
VERIFIED ANSWERS GRADED A+
1. SCUBA: Self contained underwater breathing apparatus
2. What is the pressure change for each 10m/33ft of depth change? -CORRECT ANSWER-- 1 bar/1 ata/1
atmosphere
3. What is the relationship between my depth in water and the pressure? -CORRECT ANSWER-- The
deeper you go in water, the more the pressure increases
Pressure is expressed as the weight of air
4. What is the relationship between pressure, and the volume and the density of air? -CORRECT
ANSWER-- As pressure increases, the gas volume decreases and the gas density increases
5. If I take a volume of air from one depth to another depth, how much will the volume and density change?
CORRECT ANSWER--
Volume will be 1/ata#
Density will be ata#
6. What 3 major body air spaces does increasing pressure affect as I de- scend? -CORRECT ANSWER-- Ea
sinuses, mask
7. What is a "squeeze"? -CORRECT ANSWER-- The discomfort caused by pressure imbalance pulling tissue into
the air space
8. What is "equalization"? -CORRECT ANSWER-- The addition of air to your air spaces as you descend
9. How do I equalize as I descend? -CORRECT ANSWER-- For ears and sinuses, pinch your nose and
blow gently, or wiggle your jaw and swallow
For mask, blow into it with nose
10. How often should I equalize? -CORRECT ANSWER-- Every meter/few feet, BEFORE you feel discom- fort
11. What should I do if I can't equalize? -CORRECT ANSWER-- Stop your descent, signal problem and
point to your ear, ascend a bit, and try again
12. What can happen if I don't or can't equalize gently and keep descending?-
: Fluid can rupture the eardrum Bruising around the face
can occur
13. Why does a congestion from a cold or allergy temporarily keep me from diving? -CORRECT
ANSWER-- Congestion might block normal air flow, making equalization difficult or impossible
14. Why should I never dive with earplugs? -CORRECT ANSWER-- They create air spaces that you can't
equalize
15. What other body air spaces are affected by increasing pressure? How do I equalize them? -
CORRECT ANSWER-- In filled teeth - go to a dentist
In a dry suit - learn from an instructor Lungs - breathe
,normally and continuously
16. What is the most important rule in scuba diving? -CORRECT ANSWER-- Breathe continuously and never
hold your breath
, 17. What can happen if I don't follow the most important rule in scuba diving?-
: Your lungs will over expand and rupture
18. What is a "reverse block"? -CORRECT ANSWER-- When expanding air becomes trapped in your body air
spaces as you ascend
19. What should I do if I feel discomfort in my ears, sinuses, stomach, in- testines, or teeth while
ascending? -CORRECT ANSWER-- Stop your ascent and descend a meter/few feet to reduce discomfort and
give trapped air time to work its way out
20. How does depth affect how long my air supply lasts? -CORRECT ANSWER-- The deeper you are, the
more dense air you breathe, and the faster you use the air in your cylinder. Compared to the surface, air supply
lasts 1/#ata as long along with other factors
21. What's the most efficient way to breathe dense air underwater? -CORRECT ANSWER-- Take slow, deep
breaths
22. How do I breathe to reduce anxiety when under stress? -CORRECT ANSWER-- Do NOT breathe faster -
keep breathing slowly
23. What are my 4 breathing rules as a scuba diver? -CORRECT ANSWER-- 1. Breathe continuously and neve
hold your breath
2. Breathe slowly and deeply
3. Don't allow yourself to get winded or out of breath
4. If faced with a problem, stop, and reduce anxiety by breathing slowly and deeply
24. What is buoyancy? -CORRECT ANSWER-- An upward force acting on an object in the water, canceling the p
of gravity
25. What causes buoyancy? -CORRECT ANSWER-- The upwards force is caused by the water displaced
by the object, and is equal to the weight of displaced water
26. positive buoyancy: The object weighs less than the water it displaces, so it floats
27. neutral buoyancy: The object weighs the same as the water it displaces, neither sinking nor floating
28. negative buoyancy: The object weighs more than the water it displaces, so it sinks
29. Why does salt water cause more buoyancy than fresh water? -CORRECT ANSWER-- It has dis-
solved minerals in it, so a given volume weighs more than fresh water
30. What 2 pieces of equipment do I normally use to control buoyancy? -CORRECT ANSWER--
The weight system and the BCD (buoyancy control device)
31. How does descending affect my buoyancy? -CORRECT ANSWER-- The volume decreases, reduc- ing
buoyancy, so you ADD air to the BC
32. How does ascending affect my buoyancy? -CORRECT ANSWER-- The volume increases, adding
buoyancy, so you RELEASE air from the BC
VERIFIED ANSWERS GRADED A+
1. SCUBA: Self contained underwater breathing apparatus
2. What is the pressure change for each 10m/33ft of depth change? -CORRECT ANSWER-- 1 bar/1 ata/1
atmosphere
3. What is the relationship between my depth in water and the pressure? -CORRECT ANSWER-- The
deeper you go in water, the more the pressure increases
Pressure is expressed as the weight of air
4. What is the relationship between pressure, and the volume and the density of air? -CORRECT
ANSWER-- As pressure increases, the gas volume decreases and the gas density increases
5. If I take a volume of air from one depth to another depth, how much will the volume and density change?
CORRECT ANSWER--
Volume will be 1/ata#
Density will be ata#
6. What 3 major body air spaces does increasing pressure affect as I de- scend? -CORRECT ANSWER-- Ea
sinuses, mask
7. What is a "squeeze"? -CORRECT ANSWER-- The discomfort caused by pressure imbalance pulling tissue into
the air space
8. What is "equalization"? -CORRECT ANSWER-- The addition of air to your air spaces as you descend
9. How do I equalize as I descend? -CORRECT ANSWER-- For ears and sinuses, pinch your nose and
blow gently, or wiggle your jaw and swallow
For mask, blow into it with nose
10. How often should I equalize? -CORRECT ANSWER-- Every meter/few feet, BEFORE you feel discom- fort
11. What should I do if I can't equalize? -CORRECT ANSWER-- Stop your descent, signal problem and
point to your ear, ascend a bit, and try again
12. What can happen if I don't or can't equalize gently and keep descending?-
: Fluid can rupture the eardrum Bruising around the face
can occur
13. Why does a congestion from a cold or allergy temporarily keep me from diving? -CORRECT
ANSWER-- Congestion might block normal air flow, making equalization difficult or impossible
14. Why should I never dive with earplugs? -CORRECT ANSWER-- They create air spaces that you can't
equalize
15. What other body air spaces are affected by increasing pressure? How do I equalize them? -
CORRECT ANSWER-- In filled teeth - go to a dentist
In a dry suit - learn from an instructor Lungs - breathe
,normally and continuously
16. What is the most important rule in scuba diving? -CORRECT ANSWER-- Breathe continuously and never
hold your breath
, 17. What can happen if I don't follow the most important rule in scuba diving?-
: Your lungs will over expand and rupture
18. What is a "reverse block"? -CORRECT ANSWER-- When expanding air becomes trapped in your body air
spaces as you ascend
19. What should I do if I feel discomfort in my ears, sinuses, stomach, in- testines, or teeth while
ascending? -CORRECT ANSWER-- Stop your ascent and descend a meter/few feet to reduce discomfort and
give trapped air time to work its way out
20. How does depth affect how long my air supply lasts? -CORRECT ANSWER-- The deeper you are, the
more dense air you breathe, and the faster you use the air in your cylinder. Compared to the surface, air supply
lasts 1/#ata as long along with other factors
21. What's the most efficient way to breathe dense air underwater? -CORRECT ANSWER-- Take slow, deep
breaths
22. How do I breathe to reduce anxiety when under stress? -CORRECT ANSWER-- Do NOT breathe faster -
keep breathing slowly
23. What are my 4 breathing rules as a scuba diver? -CORRECT ANSWER-- 1. Breathe continuously and neve
hold your breath
2. Breathe slowly and deeply
3. Don't allow yourself to get winded or out of breath
4. If faced with a problem, stop, and reduce anxiety by breathing slowly and deeply
24. What is buoyancy? -CORRECT ANSWER-- An upward force acting on an object in the water, canceling the p
of gravity
25. What causes buoyancy? -CORRECT ANSWER-- The upwards force is caused by the water displaced
by the object, and is equal to the weight of displaced water
26. positive buoyancy: The object weighs less than the water it displaces, so it floats
27. neutral buoyancy: The object weighs the same as the water it displaces, neither sinking nor floating
28. negative buoyancy: The object weighs more than the water it displaces, so it sinks
29. Why does salt water cause more buoyancy than fresh water? -CORRECT ANSWER-- It has dis-
solved minerals in it, so a given volume weighs more than fresh water
30. What 2 pieces of equipment do I normally use to control buoyancy? -CORRECT ANSWER--
The weight system and the BCD (buoyancy control device)
31. How does descending affect my buoyancy? -CORRECT ANSWER-- The volume decreases, reduc- ing
buoyancy, so you ADD air to the BC
32. How does ascending affect my buoyancy? -CORRECT ANSWER-- The volume increases, adding
buoyancy, so you RELEASE air from the BC
