PADI Open Water Diver Certification
SCUBA - Self contained underwater breathing apparatus
What is the pressure change for each 10m/33ft of depth change? - ANS - 1 bar/1 ata/1
atmosphere
What is the relationship betwe
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PADI Open Water Diver Certification
SCUBA - Self contained underwater breathing apparatus
What is the pressure change for each 10m/33ft of depth change? - ANS - 1 bar/1 ata/1
atmosphere
What is the relationship between my depth in water and the pressure? - ANS - 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? - ANS - 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? - ANS - Volume will be 1/ata#
Density will be ata#
What 3 major body air spaces does increasing pressure affect as I descend? - ANS - Ears,
sinuses, mask
What is a "squeeze"? - ANS - The discomfort caused by pressure imbalance pulling tissue into
the air space
What is "equalization"? - ANS - The addition of air to your air spaces as you descend
How do I equalize as I descend? - ANS - 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? - ANS - Every meter/few feet, BEFORE you feel discomfort
What should I do if I can't equalize? - ANS - 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? - ANS - 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? - ANS -
Congestion might block normal air flow, making equalization difficult or impossible
Why should I never dive with earplugs? - ANS - They create air spaces that you can't equalize
What other body air spaces are affected by increasing pressure? How do I equalize them? - ANS
- 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? - ANS - Breathe continuously and never hold
your breath
What can happen if I don't follow the most important rule in scuba diving? - ANS - Your lungs
will over expand and rupture
What is a "reverse block"? - ANS - 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? - ANS - 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? - ANS - 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? - ANS - Take slow, deep breaths
How do I breathe to reduce anxiety when under stress? - ANS - Do NOT breathe faster - keep
breathing slowly
What are my 4 breathing rules as a scuba diver? - ANS - 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? - ANS - An upward force acting on an object in the water, canceling the pull
of gravity
What causes buoyancy? - ANS - The upwards force is caused by the water displaced by the
object, and is equal to the weight of displaced water
positive buoyancy - ANS - The object weighs less than the water it displaces, so it floats
neutral buoyancy - ANS - The object weighs the same as the water it displaces, neither sinking
nor floating
negative buoyancy - ANS - The object weighs more than the water it displaces, so it sinks
Why does salt water cause more buoyancy than fresh water? - ANS - It has dissolved minerals in
it, so a given volume weighs more than fresh water
What 2 pieces of equipment do I normally use to control buoyancy? - ANS - The weight system
and the BCD (buoyancy control device)
How does descending affect my buoyancy
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