SDI Open Water Exam 2025 Questions
and Answers
What is the absolute pressure (in atm) at 66 feet? - ANSWER-2 atm
What will be the volume in a ball that is filled with two cubic feet of air at 99 feet
when it's taken to the surface? - ANSWER-8 cubic feet
How many more times dense is the air in a balloon at 4 atm compared to the air
density at the surface? - ANSWER-4 X as dense
What is the abbreviation for an atmosphere? - ANSWER-atm
If a scuba cylindar lasts 2 hours (120 minutes) at sea level, how long will it last at
66 feet? - ANSWER-40 minutes
How often should a diver equalize during a descent? - ANSWER-Early and often
What should you do if you experience discomfort in your ears while descending? -
ANSWER-Stop descent, ascend a few feet. Equalize, then descend again.
What is a reverse block? - ANSWER-Pressure caused by air spaces in your body
expanding during ascent.
COPYRIGHT ©️ 2025 ALL RIGHTS RESERVED...TRUSTED & VERIFIED 1
, What is squeeze? - ANSWER-The painful compression of air spaces in your body
or equipment during descent.
What should you do if you experience a reverse block upon ascending? -
ANSWER-Descend a few feet until the pain subsides. Wait a few moments. Then,
ascend again.
What is the most important rule in scuba diving? - ANSWER-Never hold your
breath!
What is the most serious injury that a diver can suffer from if they hold their
breath while ascending? - ANSWER-Lung over-expansion injury (possibly fatal)
Which gas component in air causes decompression sickness and narcosis? -
ANSWER-Nitrogen
What medical problem can occur if a diver ascends much too rapidly for nitrogen
to be slowly released, or off-gassed? - ANSWER-Decompression Sickness
List at least 5 factors that can predispose a diver to decompression sickness. -
ANSWER-1. Obesity
2. Age
3. Illness
4. Past/Present Injuries
5. Prior History of DCS
COPYRIGHT ©️ 2025 ALL RIGHTS RESERVED...TRUSTED & VERIFIED 2
and Answers
What is the absolute pressure (in atm) at 66 feet? - ANSWER-2 atm
What will be the volume in a ball that is filled with two cubic feet of air at 99 feet
when it's taken to the surface? - ANSWER-8 cubic feet
How many more times dense is the air in a balloon at 4 atm compared to the air
density at the surface? - ANSWER-4 X as dense
What is the abbreviation for an atmosphere? - ANSWER-atm
If a scuba cylindar lasts 2 hours (120 minutes) at sea level, how long will it last at
66 feet? - ANSWER-40 minutes
How often should a diver equalize during a descent? - ANSWER-Early and often
What should you do if you experience discomfort in your ears while descending? -
ANSWER-Stop descent, ascend a few feet. Equalize, then descend again.
What is a reverse block? - ANSWER-Pressure caused by air spaces in your body
expanding during ascent.
COPYRIGHT ©️ 2025 ALL RIGHTS RESERVED...TRUSTED & VERIFIED 1
, What is squeeze? - ANSWER-The painful compression of air spaces in your body
or equipment during descent.
What should you do if you experience a reverse block upon ascending? -
ANSWER-Descend a few feet until the pain subsides. Wait a few moments. Then,
ascend again.
What is the most important rule in scuba diving? - ANSWER-Never hold your
breath!
What is the most serious injury that a diver can suffer from if they hold their
breath while ascending? - ANSWER-Lung over-expansion injury (possibly fatal)
Which gas component in air causes decompression sickness and narcosis? -
ANSWER-Nitrogen
What medical problem can occur if a diver ascends much too rapidly for nitrogen
to be slowly released, or off-gassed? - ANSWER-Decompression Sickness
List at least 5 factors that can predispose a diver to decompression sickness. -
ANSWER-1. Obesity
2. Age
3. Illness
4. Past/Present Injuries
5. Prior History of DCS
COPYRIGHT ©️ 2025 ALL RIGHTS RESERVED...TRUSTED & VERIFIED 2
