Padi Open Water
Positive Buoyancy - correct answerThe tendency of an object to float or rise in a fluid because the object
weighs less than the fluid it displaces
Neutral Buoyancy - correct answerA condition in which an object's mass equals the mass it displaces in a
surrounding medium. The object neither sinks nor floats.
Negative Buoyancy - correct answerThe tendency of an object to sink in a fluid because the object
weighs more than the fluid it displaces
What equipment do you use to control your buoyancy - correct answerBCD (buoyancy control device) &
lead weights
and also your lungs by breathing out (sink) and in (float)
Salt water weighs more than fresh making you.. - correct answermore buoyant
Why do you usually only feel changes of pressure in your body air spaces - correct answerYour body is
primarily liquid, which is incompressible and distributes pressure equally throughout the body.
Why are pressure changes while ascending or descending underwater much more substantial than
pressure changes when doing the same in air - correct answerWater is much denser and heavier than
air, pressure changes much more significantly for a given distance ascent or descent.
Air pressure at sea level is - correct answerStandard Atmospheric Pressure 1 ata or 1 bar
How many ata/bar do you add for every ten meters you descend under water - correct answer1 ata/bar
for each 10m/33ft you descend
10m/33ft 2 bar/ata
20m/66ft 3 bar/ata
, 30m/99ft 4 bar/ata
What is the relationship between air volume and density - correct answeras pressure increases volume
decreases:
at 10m/33ft you have 1/2 volume (2bar)
at 20m/66ft you have 1/3 volume (3bar)
at 30m/99ft you have 1/4 volume (4bar)
what do you do to maintain air volume as you descend? - correct answeryou need to add air to the
space to keep up with the volume reduction (equalization)
if you added air to a space to maintain its volume while under pressure what happens to that air as the
pressure decreases - as you ascend - correct answerthe air expands
what two air spaces should concern you as a diver - correct answerears & sinuses
what is squeeze - correct answera pressure imbalance in which pressure outside an air space exceeds
pressure inside an air space resulting in pain or discomfort (ears, sinuses, lungs, teeth can squeeze)
how can you avoid discomfort from squeeze - correct answeradd air to the space during descent
(equalization)
lungs automatically equalize as you... - correct answerbreathe!
three ways to equalize during descent - correct answer1. pinch nose and gently blow
2. swallow and wiggle jaw side to side
3. swallow, wiggle jaw and blow with nose pinched
how often should you equalize during descent - correct answerevery meter/few feet before you feel any
discomfort
Positive Buoyancy - correct answerThe tendency of an object to float or rise in a fluid because the object
weighs less than the fluid it displaces
Neutral Buoyancy - correct answerA condition in which an object's mass equals the mass it displaces in a
surrounding medium. The object neither sinks nor floats.
Negative Buoyancy - correct answerThe tendency of an object to sink in a fluid because the object
weighs more than the fluid it displaces
What equipment do you use to control your buoyancy - correct answerBCD (buoyancy control device) &
lead weights
and also your lungs by breathing out (sink) and in (float)
Salt water weighs more than fresh making you.. - correct answermore buoyant
Why do you usually only feel changes of pressure in your body air spaces - correct answerYour body is
primarily liquid, which is incompressible and distributes pressure equally throughout the body.
Why are pressure changes while ascending or descending underwater much more substantial than
pressure changes when doing the same in air - correct answerWater is much denser and heavier than
air, pressure changes much more significantly for a given distance ascent or descent.
Air pressure at sea level is - correct answerStandard Atmospheric Pressure 1 ata or 1 bar
How many ata/bar do you add for every ten meters you descend under water - correct answer1 ata/bar
for each 10m/33ft you descend
10m/33ft 2 bar/ata
20m/66ft 3 bar/ata
, 30m/99ft 4 bar/ata
What is the relationship between air volume and density - correct answeras pressure increases volume
decreases:
at 10m/33ft you have 1/2 volume (2bar)
at 20m/66ft you have 1/3 volume (3bar)
at 30m/99ft you have 1/4 volume (4bar)
what do you do to maintain air volume as you descend? - correct answeryou need to add air to the
space to keep up with the volume reduction (equalization)
if you added air to a space to maintain its volume while under pressure what happens to that air as the
pressure decreases - as you ascend - correct answerthe air expands
what two air spaces should concern you as a diver - correct answerears & sinuses
what is squeeze - correct answera pressure imbalance in which pressure outside an air space exceeds
pressure inside an air space resulting in pain or discomfort (ears, sinuses, lungs, teeth can squeeze)
how can you avoid discomfort from squeeze - correct answeradd air to the space during descent
(equalization)
lungs automatically equalize as you... - correct answerbreathe!
three ways to equalize during descent - correct answer1. pinch nose and gently blow
2. swallow and wiggle jaw side to side
3. swallow, wiggle jaw and blow with nose pinched
how often should you equalize during descent - correct answerevery meter/few feet before you feel any
discomfort
