PADI Open Water Exam Study Guide
2025
When is an object positively buoyant? - correct answer-When it displaces a volume of
water weighing more than its own weight.
When is an object negatively buoyant? - correct answer-When it displaces a volume of
water weighing less than its own weight.
When is an object neutrally buoyant? - correct answer-When it displaces a volume of
water weighing the same as its own weight.
Why two pieces of equipment do you use to control your buoyancy? - correct answer-
BCD, Lead weight
What does buoyancy help with when you are underwater? - correct answer-Controlling
where you are
What does buoyancy help with when you are at the surface? - correct answer-
Floatation, conserving energy
How does the buoyancy of an object differ in fresh/salt water? - correct answer-More
buoyant in salt than fresh
When you exhale what happens? - correct answer-Lung volume decreases so you have
less buoyancy.
When you inhale what happens? - correct answer-Lung volume increases so you have
more buoyancy.
Why don't you feel air pressure? - correct answer-Your body is primarily liquid, which is
incompressible and distribute pressure equally throughout your whole body.
Where are some air spaces located in the body? - correct answer-Ears, sinuses, lungs
Do you always feel the pressure in body air spaces? - correct answer-Only if the
pressure is different inside and outside the air spaces.
1 bar is what depth? - correct answer-0m/0ft
2 bar is what depth? - correct answer-33ft/10m
, 3 bar is what depth? - correct answer-66ft/20m
4 bar is what depth? - correct answer-99ft/30m
How is air volume affected when depth is increased? - correct answer-It decreases
How is air density affected when depth is increased? - correct answer-It increases
What happens if you take an air volume underwater with you in a flexible container or
inverted jar? - correct answer-As pressure increases the volume decreases, same air
but smaller space.
How do you maintain air volume as you descend? - correct answer-Equalize
What is a "squeeze"? - correct answer-As volume decreases, pressure pushes body
tissues inwards toward air space, causing discomfort. Pressure outside air space is
more than pressure inside air space.
Where can you get a squeeze? - correct answer-Ears, sinuses, mask, lungs, teeth
How do you equalise air spaces in ears? - correct answer-Blow and squeeze nose,
wiggle jaw, swallowing
How often should you equalise? - correct answer-Every metre before discomfort
What do you do if you feel discomfort? - correct answer-Ascend until discomfort eases,
equalise, continue descent slowly
Why can't you scuba while sick? - correct answer-Congestion can plug air passages so
you can't equalize
What is mask equalisation? - correct answer-exhale into mask by nose
What does your nose need to be in the mask? - correct answer-To equalize
First rule of diving - correct answer-Always breathe continuously
What happens if you hold your breath during ascent? - correct answer-Lung over
expansion, forces air into bloodstream and chest cavity, leading to paralysis or death.
What is a reverse block? - correct answer-When air cannot escape from a air space
during ascent
How do you react to reverse block? - correct answer-Slow/stop ascent and give air time
to work its way out
2025
When is an object positively buoyant? - correct answer-When it displaces a volume of
water weighing more than its own weight.
When is an object negatively buoyant? - correct answer-When it displaces a volume of
water weighing less than its own weight.
When is an object neutrally buoyant? - correct answer-When it displaces a volume of
water weighing the same as its own weight.
Why two pieces of equipment do you use to control your buoyancy? - correct answer-
BCD, Lead weight
What does buoyancy help with when you are underwater? - correct answer-Controlling
where you are
What does buoyancy help with when you are at the surface? - correct answer-
Floatation, conserving energy
How does the buoyancy of an object differ in fresh/salt water? - correct answer-More
buoyant in salt than fresh
When you exhale what happens? - correct answer-Lung volume decreases so you have
less buoyancy.
When you inhale what happens? - correct answer-Lung volume increases so you have
more buoyancy.
Why don't you feel air pressure? - correct answer-Your body is primarily liquid, which is
incompressible and distribute pressure equally throughout your whole body.
Where are some air spaces located in the body? - correct answer-Ears, sinuses, lungs
Do you always feel the pressure in body air spaces? - correct answer-Only if the
pressure is different inside and outside the air spaces.
1 bar is what depth? - correct answer-0m/0ft
2 bar is what depth? - correct answer-33ft/10m
, 3 bar is what depth? - correct answer-66ft/20m
4 bar is what depth? - correct answer-99ft/30m
How is air volume affected when depth is increased? - correct answer-It decreases
How is air density affected when depth is increased? - correct answer-It increases
What happens if you take an air volume underwater with you in a flexible container or
inverted jar? - correct answer-As pressure increases the volume decreases, same air
but smaller space.
How do you maintain air volume as you descend? - correct answer-Equalize
What is a "squeeze"? - correct answer-As volume decreases, pressure pushes body
tissues inwards toward air space, causing discomfort. Pressure outside air space is
more than pressure inside air space.
Where can you get a squeeze? - correct answer-Ears, sinuses, mask, lungs, teeth
How do you equalise air spaces in ears? - correct answer-Blow and squeeze nose,
wiggle jaw, swallowing
How often should you equalise? - correct answer-Every metre before discomfort
What do you do if you feel discomfort? - correct answer-Ascend until discomfort eases,
equalise, continue descent slowly
Why can't you scuba while sick? - correct answer-Congestion can plug air passages so
you can't equalize
What is mask equalisation? - correct answer-exhale into mask by nose
What does your nose need to be in the mask? - correct answer-To equalize
First rule of diving - correct answer-Always breathe continuously
What happens if you hold your breath during ascent? - correct answer-Lung over
expansion, forces air into bloodstream and chest cavity, leading to paralysis or death.
What is a reverse block? - correct answer-When air cannot escape from a air space
during ascent
How do you react to reverse block? - correct answer-Slow/stop ascent and give air time
to work its way out
