1 | P a g e | © copyright 2024/2025 | Grade A+
SDI Open Water Set Questions and
Answers | Latest Update 2024/2025
What is the absolute pressure (in atm) at 66 feet?
✓ ~~> 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?
✓ ~~> 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?
✓ ~~> 4 X as dense
What is the abbreviation for an atmosphere?
✓ ~~> atm
If a scuba cylindar lasts 2 hours (120 minutes) at sea level, how long will it last
at 66 feet?
✓ ~~> 40 minutes
How often should a diver equalize during a descent?
✓ ~~> Early and often
Master01 | September, 2024/2025 | Latest update
, 2 | P a g e | © copyright 2024/2025 | Grade A+
What should you do if you experience discomfort in your ears while
descending?
✓ ~~> Stop descent, ascend a few feet. Equalize, then descend again.
What is a reverse block?
✓ ~~> Pressure caused by air spaces in your body expanding during
ascent.
What is squeeze?
✓ ~~> 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?
✓ ~~> Descend a few feet until the pain subsides. Wait a few moments.
Then, ascend again.
What is the most important rule in scuba diving?
✓ ~~> Never hold your breath!
What is the most serious injury that a diver can suffer from if they hold their
breath while ascending?
✓ ~~> Lung over-expansion injury (possibly fatal)
Master01 | September, 2024/2025 | Latest update
, 3 | P a g e | © copyright 2024/2025 | Grade A+
Which gas component in air causes decompression sickness and narcosis?
✓ ~~> Nitrogen
What medical problem can occur if a diver ascends much too rapidly for
nitrogen to be slowly released, or off-gassed?
✓ ~~> Decompression Sickness
List at least 5 factors that can predispose a diver to decompression sickness.
✓ ~~> 1. Obesity
2. Age
3. Illness
4. Past/Present Injuries
5. Prior History of DCS
6. Fatigue
7. Dehydration
8. Smoke inhalation
9. Use of drugs/alcohol prior to dive
10. Repetative Dives
11. Overexertion
12. Cold Water
13. Diving at higher altitudes
Describe the symptoms of DCS, including mild to severe signs and symptoms.
Master01 | September, 2024/2025 | Latest update
SDI Open Water Set Questions and
Answers | Latest Update 2024/2025
What is the absolute pressure (in atm) at 66 feet?
✓ ~~> 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?
✓ ~~> 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?
✓ ~~> 4 X as dense
What is the abbreviation for an atmosphere?
✓ ~~> atm
If a scuba cylindar lasts 2 hours (120 minutes) at sea level, how long will it last
at 66 feet?
✓ ~~> 40 minutes
How often should a diver equalize during a descent?
✓ ~~> Early and often
Master01 | September, 2024/2025 | Latest update
, 2 | P a g e | © copyright 2024/2025 | Grade A+
What should you do if you experience discomfort in your ears while
descending?
✓ ~~> Stop descent, ascend a few feet. Equalize, then descend again.
What is a reverse block?
✓ ~~> Pressure caused by air spaces in your body expanding during
ascent.
What is squeeze?
✓ ~~> 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?
✓ ~~> Descend a few feet until the pain subsides. Wait a few moments.
Then, ascend again.
What is the most important rule in scuba diving?
✓ ~~> Never hold your breath!
What is the most serious injury that a diver can suffer from if they hold their
breath while ascending?
✓ ~~> Lung over-expansion injury (possibly fatal)
Master01 | September, 2024/2025 | Latest update
, 3 | P a g e | © copyright 2024/2025 | Grade A+
Which gas component in air causes decompression sickness and narcosis?
✓ ~~> Nitrogen
What medical problem can occur if a diver ascends much too rapidly for
nitrogen to be slowly released, or off-gassed?
✓ ~~> Decompression Sickness
List at least 5 factors that can predispose a diver to decompression sickness.
✓ ~~> 1. Obesity
2. Age
3. Illness
4. Past/Present Injuries
5. Prior History of DCS
6. Fatigue
7. Dehydration
8. Smoke inhalation
9. Use of drugs/alcohol prior to dive
10. Repetative Dives
11. Overexertion
12. Cold Water
13. Diving at higher altitudes
Describe the symptoms of DCS, including mild to severe signs and symptoms.
Master01 | September, 2024/2025 | Latest update
