PADI Open Water Diver 4 — Questions and Answers
Question 1: What should you do if you experience a muscle cramp in your leg while diving?
- Immediately ascend to the surface
- Stop, relax, stretch the cramped muscle, then continue or ascend (Correct answer)
- Signal your buddy and have them pull you to shore
- Descend deeper to relieve the pressure
Correct answer: Stop, relax, stretch the cramped muscle, then continue or ascend
Stopping and stretching the cramped muscle while relaxing typically resolves leg cramps; you may then continue the dive or ascend as needed.
Question 2: Which of the following is a symptom of decompression sickness (DCS)?
- Increased appetite immediately after surfacing
- Joint pain, dizziness, or numbness after a dive (Correct answer)
- Temporary color blindness while underwater
- Rapid heart rate only during descent
Correct answer: Joint pain, dizziness, or numbness after a dive
DCS symptoms include joint pain ('the bends'), dizziness, numbness, weakness, and rashes appearing after surfacing from a dive.
Question 3: What is the first aid treatment for a diver suspected of having decompression sickness?
- Have them re-enter the water and descend slowly
- Administer 100% oxygen and seek emergency medical care (Correct answer)
- Give them plenty of water and have them rest
- Apply heat packs to affected joints
Correct answer: Administer 100% oxygen and seek emergency medical care
Administering 100% oxygen and getting the diver to emergency medical care (including hyperbaric treatment) is the correct first aid for DCS.
Question 4: What does a 'kelp bed' environment require divers to be especially careful about?
- Rapid temperature changes causing hypothermia
- Entanglement in the plant growth (Correct answer)
- Reduced visibility from bioluminescence
- Increased current from wave action
Correct answer: Entanglement in the plant growth
Kelp beds pose an entanglement risk; divers should move slowly, keep equipment streamlined, and know how to calmly free themselves if tangled.
Question 5: Which factor most affects how long a scuba tank will last during a dive?
- Water temperature
- Depth and breathing rate (Correct answer)
- Type of wetsuit worn
- Color of the tank
Correct answer: Depth and breathing rate
Depth increases air consumption because each breath at depth uses more compressed air, and a higher breathing rate further depletes the tank faster.
Question 6: What is the purpose of the 'rule of thirds' in cave or overhead diving?
- Use one-third of air going in, one-third coming out, and keep one-third in reserve (Correct answer)
- Dive in groups of three for safety
- Always turn back after one-third of your dive time
- Reserve the final third of the dive for ascent
Correct answer: Use one-third of air going in, one-third coming out, and keep one-third in reserve
The rule of thirds means using one-third of your air supply to enter, one-third to exit, and holding one-third in reserve for emergencies.
Question 7: What effect does cold water have on a diver's air consumption?
- It decreases air consumption because breathing slows
- It has no measurable effect on air consumption
- It can increase air consumption as the body works harder to stay warm (Correct answer)
- It reduces nitrogen absorption significantly
Correct answer: It can increase air consumption as the body works harder to stay warm
Cold water causes the body to work harder to maintain core temperature, which can increase breathing rate and thus air consumption.
PADI Open Water Diver 4
What should you do if you experience a muscle cramp in your leg while diving?