SDI (Scuba Diving International) Part 2 Questions and Correct Answers

What is the absolute pressure (in atmospheres/bars, ATM) at 20 meters(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/bar compared to the air density at the surface? 4x (4 times) If a scuba cylinder lasts 2 hours at sea level, how long will it last at 20 meters (66 feet)? 40 minutes How often should a scuba diver equalize during a descent? at the surface and every couple of feet as you descend. What should you do if you experience discomfort in your ears upon descending? Stop and ascend a few feet until you no longer feel any discomfort. Try to equalize again and continue with your descent. What is a reverse block? When air cannot escape from a air space during ascent What should you do if you experience a reverse block upon ascending? Descend a couple of feet until the pain subsides, wait a minute, and continue your ascent. What is the most important rule in scuba diving? keep breathing and never hold your breath What is the most serious injury that a diver could suffer from if they hold their breath upon ascending? lung over-expansion injury or ruptured lung 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? It can come out of solution into your blood making bubbles which collect at your joints causing the bends or decompression sickness.