Scuba Diving Study Guide 2026
Everything you need to pass the Scuba Diving exam in one place: the exam format, every topic to study, real practice questions with explanations, flashcards, and full-length practice tests. Free, no sign-up needed.
📚 Scuba Diving Topics to Study (21)
✍️ Sample Scuba Diving Questions & Answers
1. What causes a rip current, and how should a diver handle one at the surface?
Rip currents form when water channeled through a gap flows seaward in a narrow, fast stream; swimming parallel to shore escapes the narrow channel rather than exhausting oneself fighting it.
2. What physical phenomenon explains why objects underwater appear approximately 25% larger and 25% closer than they actually are?
Light refracts (bends) as it passes from water into the air space inside the mask, creating a virtual image that appears roughly 25% larger and closer than reality.
3. What is the purpose of a scuba mask purge valve?
A purge valve on a mask allows divers to exhale through the nose to push out any water that has flooded the mask.
4. How much does absolute pressure increase for every 33 feet (10 meters) of seawater depth?
Seawater pressure increases by 1 atmosphere (14.7 psi) for every 33 feet (10 m) of depth, so at 33 ft the absolute pressure is 2 ATM total.
5. During a dive, a diver notices their ears feel full and painful at 15 feet. This is most likely caused by:
As pressure increases on descent, the middle ear space must be equalized by opening the Eustachian tube; failure causes a pressure squeeze that creates pain and risks rupturing the eardrum.
6. What is the main reason divers are advised not to touch marine life?
Many marine animals have protective mucus coatings that human hands damage, and handling causes stress responses that can injure or kill the animal.