SDI Certification Exam Review Questions and Answers Already Passed

SDI Certification Exam Review Questions and Answers Already Passed What does SCUBA stand for? Self Contained Underwater Breathing Apparatus List the three important scuba diving changes that occurred in the 1950s 1) Dive tables published for repetitive dives 2) Improved design/quality of scuba gear 3) Dive computers commercially available Name three different devices that modern dive computers replace Depth gauge, dive tables, watch What sets SDI apart from other training agencies? Students use a personal dive computer for all instruction and certification dives How much larger and closer do objects appear under water and why? 33% larger, 25% closer Light bends in the air-space between the lens and your eyes. How much faster does sound move through water than air and why? 4 times faster in water Water is 800x denser than air; sound travels through denser mediums at faster rates What is the first color absorbed underwater? RED (followed by OYGBIV) When diving from shore, the best time to dive is when there is the least amount of tidal current. _____ tide is when there is no horizontal water movement. Slack If you are caught in a rip current, first swim _____ to the current to get out of it before swimming towards shore. Perpendicular Start your dive by swimming ____ the current into/against Global currents are _____. Local currents ____. Fixed Fluctuate Rip current Current which goes seaward due to ocean floor stuctures Long shore current Flows parallel to shore Waves are caused by energy generated by WIND Tides are caused by polarity of the moon T/F: Anticipate surge action to avoid contact with stationary objects. True What is surge Back and forth motion underwater which you shouldn't fight; move deeper and away from dangerous objects if caught in one. USE THEM TO YOUR ADVANTAGE What types of marine life cause most diving injuries Jellyfish or marine life which account for a temporary, painful sting. WATCH OUT FOR ALLERGIC REACTIONS. Injuries due to marine life typically a _____ response Defense How do you treat a sting? Hot water or vinegar What should you do if a potentially dangerous animal underwater does not leave your area? Remain still Remain calm Slowly leave area List three different reasons that it is advisable to check with your local dive center before diving in an unfamiliar area. 1) Rip currents could be prevalent 2) Thermoclines could affect thermal protection 3) YOU ARE SUBJECT TO LOCALITY (be aware of laws and regulations What is the absolute pressure in atm at 20m/66ft? 3 atm absolute What will be the volume in a ball that is filled with 2 cubic feet of air at 30 m/99ft when it is taken to the surface? 8 cubic feet How many times more dense is air in a balloon at 4 atm compared to the air density at the surface? 4 times If a scuba cylinder lasts two hours at sea level, how long will it last at 20 m/66 ft? 40 min How often should you equalize during descent? Early and often; at the surface and then every couple feet so no discomfort is felt What should you do if you experience discomfort in your ears upon descending? Immediately stop descending and ascend a few feet until you are shallow enough not to feel any discomfort What is reverse block? Occurs when air cannot expand or escape freely when ascending What should you do if you experience a reverse block upon ascending? Descend a couple feet and stay there until air has time to vent What is the most important rule in scuba diving? Do not hold your breath, breathe continuously What is the most serious injury that a diver could suffer from if they hold their breathe upon ascending? Lung overexpansion injuries Which gas component in air causes decompression sickness and narcosis? Nitrogen What medical can occur if a diver ascends much too rapidly for nitrogen to be slowly released? Decompression sickness List five factors that can predispose a diver to decompression sickenss Illness, ascending too fast, dehydration, smoking, alcohol consumption Describe the symptoms of DCS Rash from bubbles in skin capillaries, joint pain, difficulty inhaling, loss of sensation, paralysis, could be fatal How to treat a diver with decompression sickness Bring diver to surface, seek immediate medical attention, administer pure oxygen, place person in pressure chamber What is the depth threshold where most scuba divers generally begin to be affected by nitrogen narcosis? 30 msw/100fsw List two feelings of being "narked" Euphoric, anxious How to do alleviate the symptoms of nitrogen narcosis? Ascend normally until you no longer feel effects What gas causes extreme headache and nausea, unconsciousness, and bright redness of the fingernail beds and lips? Carbon monoxide What may indicate that the air in the scuba cylinder is contaminated? Air has odor or taste What should you do if you suddenly feel sick and develop a headache during a scuba dive? Abort dive and controlled ascent. Breathe fresh air or oxygen As pressure increases Volume decreases What is the main purpose of a snorkel? Allows you to conserve air from your scuba cylinder at long intervals of time at the surface How do you know if your mask fits correctly? Will tighten to your face and won't fall off via suction through your nose Name one audible and one visual rescue signal device Whistle/horn Bright-colored lift bag Name two basic fin designs Full-foot and open-heel What is the main difference between a wet suit and a dry suit? Dry suit is designed with an integrated inflation system to keep body completely out of contact with water. Dry suits keep divers completely dry for use in cold water (below 50 degrees) What extra attire can provide warmth? Hood, hooded vests, boots, gloves, caps List the four functions of a dive computer Depth, dive time, ascent rate, surface interval time Define no-stop time Amount of time remaining at any point during the dive before a necessary decompression stop What two ways do a PDC alert you on ascending too fast? Blink and ascent alarm How do you determine a time limit a repetitive dive from a PDC? Surface mode shows depths ranging every ten feet with the no-stop time limits adjusted for current depth What are the two modes of operation of a dive computer? Surface and dive modes What are the two types of weight systems? Weight belt Weight-integrated BCD What are the two types of dive flags? International flag Diver-down flag Describe the function of regulator first stage and second stage First stage - attaches to tank valve and reduces the high-pressure air to intermediate pressure Second stage - delivers air at ambient pressure directly to the diver Cylinders should be visually inspected ____ a year and hydrostatically tested every ____ years Once; five What does BCD stand for? Buoyancy Compensator Device Describe two important features of a weight system Quick release mechanism, evenly-dispersed lead Name the four water entries Controlled seated entry Back roll entry Giant stride entry Shore entry Define risk management Way of preventing problems and planning a response to any emergency Name the steps of the buddy check ABCs Air Buoyancy Computer Dive Gear Enter water What should you do is you lose your buddy? Look around for no more than 1 minute then ascend to surface; if not at surface call for help How do you conduct a safety stop? Conducted at 15 ft for 3-5 minutes before surfacing How much air should remain in your cylinder upon completing a dive? 500 psi What two ways do a PDC alert you on ascending too fast?