SDI Open Water Questions
with correct simplified Answers
What is the absolute pressure (in atm) at 66 feet? - correct 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? - correct 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? -
correct answer-4 X as dense
What is the abbreviation for an atmosphere? - correct answer-atm
If a scuba cylindar lasts 2 hours (120 minutes) at sea level, how long will it last at 66 feet? - correct
answer-40 minutes
How often should a diver equalize during a descent? - correct answer-Early and often
What should you do if you experience discomfort in your ears while descending? - correct answer-Stop
descent, ascend a few feet. Equalize, then descend again.
What is a reverse block? - correct answer-Pressure caused by air spaces in your body expanding during
ascent.
What is squeeze? - correct 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? - correct 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? - correct answer-Never hold your breath!
What is the most serious injury that a diver can suffer from if they hold their breath while ascending? -
correct answer-Lung over-expansion injury (possibly fatal)
Which gas component in air causes decompression sickness and narcosis? - correct answer-Nitrogen
What medical problem can occur if a diver ascends much too rapidly for nitrogen to be slowly released,
or off-gassed? - correct answer-Decompression Sickness
List at least 5 factors that can predispose a diver to decompression sickness. - correct answer-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. - correct answer-1. Rash or
Crackling Skin
2. Joint Pain (most common symptom)
with correct simplified Answers
What is the absolute pressure (in atm) at 66 feet? - correct 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? - correct 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? -
correct answer-4 X as dense
What is the abbreviation for an atmosphere? - correct answer-atm
If a scuba cylindar lasts 2 hours (120 minutes) at sea level, how long will it last at 66 feet? - correct
answer-40 minutes
How often should a diver equalize during a descent? - correct answer-Early and often
What should you do if you experience discomfort in your ears while descending? - correct answer-Stop
descent, ascend a few feet. Equalize, then descend again.
What is a reverse block? - correct answer-Pressure caused by air spaces in your body expanding during
ascent.
What is squeeze? - correct 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? - correct 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? - correct answer-Never hold your breath!
What is the most serious injury that a diver can suffer from if they hold their breath while ascending? -
correct answer-Lung over-expansion injury (possibly fatal)
Which gas component in air causes decompression sickness and narcosis? - correct answer-Nitrogen
What medical problem can occur if a diver ascends much too rapidly for nitrogen to be slowly released,
or off-gassed? - correct answer-Decompression Sickness
List at least 5 factors that can predispose a diver to decompression sickness. - correct answer-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. - correct answer-1. Rash or
Crackling Skin
2. Joint Pain (most common symptom)
