PADI Open Water Diver Certification – Study Guide, Key Concepts & Practice
Questions Review
SCUBA - correct answer ✔✔Self-contained underwater breathing apparatus
What is the pressure change for each 10m/33ft of depth change? - correct answer ✔✔1 bar/1
ata/1 atmosphere
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
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
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#
What 3 major body air spaces does increasing pressure affect as I descend? - correct answer
✔✔Ears, sinuses, mask
What is a "squeeze"? - correct answer ✔✔The discomfort caused by pressure imbalance pulling
tissue into the air space
What is "equalization"? - correct answer ✔✔The addition of air to your air spaces as you
descend
,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
How often should I equalize? - correct answer ✔✔Every meter/few feet, BEFORE you feel
discomfort
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
What can happen if I don't or can't equalize gently and keep descending? - correct answer
✔✔Fluid can rupture the eardrum
Bruising around the face can occur
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
Why should I never dive with earplugs? - correct answer ✔✔They create air spaces that you
can't equalize
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
What is the most important rule in scuba diving? - correct answer ✔✔Breathe continuously and
never hold your breath
, What can happen if I don't follow the most important rule in scuba diving? - correct answer
✔✔Your lungs will over expand and rupture
What is a "reverse block"? - correct answer ✔✔When expanding air becomes trapped in your
body air spaces as you ascend
What should I do if I feel discomfort in my ears, sinuses, stomach, intestines, 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
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
What's the most efficient way to breathe dense air underwater? - correct answer ✔✔Take slow,
deep breaths
How do I breathe to reduce anxiety when under stress? - correct answer ✔✔Do NOT breathe
faster - keep breathing slowly
What are my 4 breathing rules as a scuba diver? - correct answer ✔✔1. Breathe continuously
and never 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
What is buoyancy? - correct answer ✔✔An upward force acting on an object in the water,
canceling the pull of gravity
Questions Review
SCUBA - correct answer ✔✔Self-contained underwater breathing apparatus
What is the pressure change for each 10m/33ft of depth change? - correct answer ✔✔1 bar/1
ata/1 atmosphere
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
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
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#
What 3 major body air spaces does increasing pressure affect as I descend? - correct answer
✔✔Ears, sinuses, mask
What is a "squeeze"? - correct answer ✔✔The discomfort caused by pressure imbalance pulling
tissue into the air space
What is "equalization"? - correct answer ✔✔The addition of air to your air spaces as you
descend
,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
How often should I equalize? - correct answer ✔✔Every meter/few feet, BEFORE you feel
discomfort
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
What can happen if I don't or can't equalize gently and keep descending? - correct answer
✔✔Fluid can rupture the eardrum
Bruising around the face can occur
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
Why should I never dive with earplugs? - correct answer ✔✔They create air spaces that you
can't equalize
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
What is the most important rule in scuba diving? - correct answer ✔✔Breathe continuously and
never hold your breath
, What can happen if I don't follow the most important rule in scuba diving? - correct answer
✔✔Your lungs will over expand and rupture
What is a "reverse block"? - correct answer ✔✔When expanding air becomes trapped in your
body air spaces as you ascend
What should I do if I feel discomfort in my ears, sinuses, stomach, intestines, 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
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
What's the most efficient way to breathe dense air underwater? - correct answer ✔✔Take slow,
deep breaths
How do I breathe to reduce anxiety when under stress? - correct answer ✔✔Do NOT breathe
faster - keep breathing slowly
What are my 4 breathing rules as a scuba diver? - correct answer ✔✔1. Breathe continuously
and never 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
What is buoyancy? - correct answer ✔✔An upward force acting on an object in the water,
canceling the pull of gravity
