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PADI Open Water Diver Certification
SCUBA - correct answer Self contained underwater breathing apparatus What is the pressure change for each 10m/33ft of depth change? - correct answer 1 bar/1 ata/1 atmosphere What is the relationship between my depth in water and the pressure? - correct answer The deeper you go in water, the more the pressure increases Pressure is expressed as the weight of air What is the relationship between pressure, and the volume and the density of air? - correct answer As pressure increases, the gas volume decreases and the gas density increases If I take a volume of air from one depth to another depth, how much will the volume and density change? - correct answer Volume will be 1/ata# Density will be ata# What 3 major body air spaces does increasing pressure affect as I descend? - correct answer Ears, sinuses, mask What is a "squeeze"? - correct answer The discomfort caused by pressure imbalance pulling tissue into the air space What is "equalization"? - correct answer The addition of air to your air spaces as you descend How do I equalize as I descend? - correct answer For ears and sinuses, pinch your nose and blow gently, or wiggle your jaw and swallow For mask, blow into it with nose
How often should I equalize? - correct answer Every meter/few feet, BEFORE you feel discomfort What should I do if I can't equalize? - correct answer Stop your descent, signal problem and point to your ear, ascend a bit, and try again What can happen if I don't or can't equalize gently and keep descending? - correct answer Fluid can rupture the eardrum Bruising around the face can occur Why does a congestion from a cold or allergy temporarily keep me from diving? - correct answer Congestion might block normal air flow, making equalization difficult or impossible Why should I never dive with earplugs? - correct answer They create air spaces that you can't equalize What other body air spaces are affected by increasing pressure? How do I equalize them? - correct answer In filled teeth - go to a dentist In a dry suit - learn from an instructor Lungs - breathe normally and continuously What is the most important rule in scuba diving? - correct answer Breathe continuously and never hold your breath What can happen if I don't follow the most important rule in scuba diving? - correct answer Your lungs will over expand and rupture What is a "reverse block"? - correct answer When expanding air becomes trapped in your body air spaces as you ascend What should I do if I feel discomfort in my ears, sinuses, stomach, intestines, or teeth while ascending? - correct answer Stop your ascent and descend a meter/few feet to reduce discomfort and give trapped air time to work its way out
Why does salt water cause more buoyancy than fresh water? - correct answer It has dissolved minerals in it, so a given volume weighs more than fresh water What 2 pieces of equipment do I normally use to control buoyancy? - correct answer The weight system and the BCD (buoyancy control device) How does descending affect my buoyancy? - correct answer The volume decreases, reducing buoyancy, so you ADD air to the BC How does ascending affect my buoyancy? - correct answer The volume increases, adding buoyancy, so you RELEASE air from the BC How does breathing affect my buoyancy? - correct answer Inhaling adds, exhaling reduces What is the buddy system? - correct answer Diving with another diver What are the 3 most important considerations in choosing scuba equipment? - correct answer Suitability, fit, and comfort How do I generally care for scuba equipment? - correct answer Rinse everything in fresh water and dry it in the shade and store in a cool, dry place Why do I need a mask? - correct answer It provides an air space so your eyes can focus because light behaves differently underwater Why does my mask need to enclose my nose? - correct answer Because the mask creates an air space, you need your nose to blow in it to equalize it Why do I need a snorkel? - correct answer It saves your air supply while your face is in the water What are 2 basic fin styles? - correct answer Full-foot and adjustable strap
What consists of your scuba kit? - correct answer Buoyancy control device, regulator, air cylinder, weight system What 5 components make up a BCD? - correct answer Inflatable bladder, harness/jacket and cylinder band, low pressure inflator (LPI) mechanism, overpressure/quick dump exhaust valve, weight system inflatable bladder - correct answer Controls buoyancy harness/jacket and cylinder band - correct answer Holds cylinder on back low pressure inflator (LPI) mechanism - correct answer Inflates bladder with air from your cylinder with the touch of a button overpressure/quick dump exhaust valve - correct answer Vents air if the bladder is overfilled weight system - correct answer Contain weight pockets that you release and drop in case of emergency What 2 special maintenance considerations do BCDs have? - correct answer Rinse the inside of the bladder with fresh water, and store them partially inflated to keep the bladder from sticking together What 5 components make up a regulator? - correct answer First stage, second stage, alternate air source, low pressure inflator (LPI) hose, submersible pressure gauge (SPG) first stage - correct answer Supplies air to all the other components, connecting to the cylinder valve by screw or clamp, reduces cylinder pressure to intermediate pressure (above surrounding pressure)
Why use more than 1 weight system? - correct answer It will help distribute weight trim - correct answer The orientation and balance of a swimmer in the water - the ideal is horizontal danger/hazard - correct answer okay - correct answer go up/end dive - correct answer something's wrong - correct answer down/descend - correct answer low on air - correct answer okay - correct answer distress/in trouble - correct answer How does being underwater affect the apparent size or distance of things? - correct answer Refraction occurs, where light changes direction, and things are magnified by 1/ How does water affect light intensity and color? - correct answer It reflects, scatters, and absorbs light in the roygbiv order As you go deeper, it gets darker How does hearing differ underwater? - correct answer It travels faster and longer
How does water's density affect moving in water? - correct answer It takes more energy the faster you try to swim What is "airway control"? - correct answer The skill of breathing past remaining water without drawing any into your throat after clearing your regulator/snorkel What are 2 techniques for airway control? - correct answer Inhaling slowly, looking down, and touching your tongue to the roof of your mouth as you inhale What are 8 symptoms of overexertion while diving? - correct answer Fatigue, labored breathing, a feeling of suffocation, weakness, anxiety, headaches, muscle cramping, and a tendency to panic What should I do if I think I'm becoming overexerted at the surface and underwater?
- correct answer Stop all activity, signal your buddy, and rest What points should a dive plan normally include? - correct answer Agree on best entry/exit techniques, decide what course you'll follow, agree on maximum time and depth, review underwater signs, determine when you will head back, agree on how you'll stay together during the dive, establish what you'll do if you become separated, discuss emergency procedures How do we conduct the predive safety check? - correct answer Using Begin With Review And Friend (BWRAF) BWRAF - correct answer BCD, weight, releases, air, final check What do I do if I get separated from my buddy on a dive? - correct answer Look for each other for no more than 1 minute, and then ascend to the surface if you can't find them How do my buddy and I manage our air supply together while diving? - correct answer Plan your dive around who breathes air the fastest.
What 4 principles affect visibility? - correct answer Water movement, weather, plankton, bottom composition When diving in a mild current, in what direction would I normally go? - correct answer Swim slowly into the current so that when you turn the dive, the current will push you back to your exit point What do I do if I'm caught in a current and am carried downstream from where I planned to dive or exit the water? - correct answer Swim perpendicular to the current What two things in the water affect a diver? - correct answer The waves and current What is assessing conditions based on? - correct answer The weather, season, water motion, water appearance, reports online and from other divers, and dives made at similar sites What should I do if I see a potentially aggressive animal underwater? - correct answer Remain still and calm. Swim away if you become uncomfortable In what depth water do waves break? - correct answer In the surf zone, in water only slightly deeper than their height surge - correct answer A back-and-forth motion caused by waves passing overhead undertow - correct answer The water of waves flowing back to sea under incoming waves rip current - correct answer When waves push water over a long obstruction and the water underneath funnels back to sea through an available opening What should I do if I get caught in a rip current? - correct answer Establish buoyancy and swim at a sustainable pace parallel to the shore
upwelling - correct answer Usually caused by wind blowing from shore, pushing surface water away, resulting in cooler, deeper water rising towards the surface to replace it What 3 environmental conditions does tide generally affect? - correct answer The current, depth, and visibility bow - correct answer The front of the boat stern - correct answer The back of the boat port - correct answer The left side of the boat as you face forward starboard - correct answer The right side of the boat as you face forward leeward - correct answer The side away from the wind windward - correct answer The side toward the wind The bridge/wheelhouse - correct answer The portion of the boat where the controls are head - correct answer The boat's toilet facilities galley - correct answer The boat's kitchen area swim step - correct answer A platform on the stern that is close to water level What are characteristics of a responsive diver? - correct answer They are breathing, alert, and active
At a minimum, how many surface signaling devices should I have with me on a dive? - correct answer At least 2 - one audible and one visual How close am I supposed to stay to a dive flag? - correct answer Within 15 m/50 ft How far away are boaters supposed to stay from a dive flag? - correct answer At least 30-60 m/100-200 ft For what 4 purposes might I carry a slate or wet book? - correct answer Communication, to note dive plan limits, to record information during the dive, and for the unexpected What information do I typically record, at a minimum, regardless of what I choose? - correct answer Date, dive site name/location, dive buddy, dive depth and duration, objective and description What can I do with dive planning software? - correct answer Estimate how long your air supply will last and estimate the time your dive computer will allow on a dive What is the composition of air to divers? - correct answer 79% nitrogen and 21% oxygen To what 4 diving related issues does the makeup of air relate? - correct answer Oxygen toxicity, contaminated air, decompression sickness, and gas narcosis How do I prevent oxygen toxicity? - correct answer The higher the oxygen content, the shallower the depth limit for using it while diving. Don't exceed 40 m/130 ft when diving recreationally What are 5 possible signs/symptoms of contaminated air? - correct answer Headache, nausea, cherry-red lips and fingernail beds, dizziness, and unconsciousness/unresponsiveness
What are the 2 primary factors that influence how much nitrogen dissolves into my body tissues during a dive? - correct answer Depth and time What is decompression sickness (DCS), or "the bends"? - correct answer When excess nitrogen in your body tissues is too high when you surface, so nitrogen comes out of solution faster than your body can eliminate it. Nitrogen bubbles will form within your blood and body tissues. What are 9 signs/symptoms of decompression sickness? - correct answer Paralysis, dizziness, tingling, joint and limb pain, shock, numbness, difficulty breathing, weakness and prolonged fatigue, unconsciousness and death When do symptoms of DCS occur? - correct answer Usually 15 minutes to 12 hours after a dive How does a dive computer or dive table estimate the amount of nitrogen I absorb during a dive? - correct answer By using your dive time and depth information to calculate the theoretical amount of nitrogen in your body What is no stop diving? - correct answer When you can swim directly to the surface without unacceptable risk of decompression sickness What is a no stop limit? - correct answer The maximum time you can spend at a given depth and still ascend to the surface What do I have to do if I exceed a no stop limit? - correct answer I must make an emergency decompression stop What is an emergency decompression stop? - correct answer Stops at specific depths for prescribed times to allow your body to release dissolved nitrogen before you ascend further What is the relationship between depth and my no stop limits? - correct answer The deeper you dive, the shorter your no stop limits
How do you fly or ascend to altitude after diving? - correct answer You start and end your dive at sea level, and then go to lower surface pressure at altitude How do you altitude dive? - correct answer You start and end your dive at lower surface pressure at altitude What are the current recommendations for flying after a single dive? - correct answer A minimum surface interval of 12 hours What are the current recommendations for flying after repetitive dives or multiday dives? - correct answer A minimum surface interval of 18 hours What are the current recommendations for flying after dives requiring emergency decompression stops? - correct answer A minimum surface interval greater than 18 hours Why are being cold and/or exerting myself strenuously issues with respect to decompression sickness risk? - correct answer You may end up with more dissolved nitrogen than calculated by your dive computer What should I do if I am cold or exert myself strenuously on a dive? - correct answer Plan dives as though they are 4 m/10 ft deeper than their actual depth What is the first aid for a diver with suspected DCI? - correct answer 1. Stop all diving
- Check for breathing and provide CPR as needed
- Contact emergency medical care
- Keep the diver lying down and provide emergency oxygen
- Monitor the diver and take steps to prevent shock
- Lay the diver level, left side down, head supported, breathing oxygen What treatment is usually required for DCI? - correct answer Being put in a recompression chamber, where the pressure put on the diver helps the body absorb the gas bubbles present
What is gas narcosis? - correct answer An intoxicating effect when many gases are put under pressure What are signs/symptoms of gas narcosis? - correct answer Feeling drunk/high, loss of coordination, slowed thinking, slowed reactions, inappropriate laughter, depression, false sense of security, ignoring or disregard for safety, anxiety or panic when you're under stress at depth How do I avoid gas narcosis and what do I do if it occurs? - correct answer Don't dive too deep and immediately ascend to a shallower depth What is a lubber line on a compass? - correct answer A straight line through the center of the compass face or along the side from the 6 o'clock to the 12 o'clock positions that is your direction of travel How should I hold a compass when navigating with it underwater? - correct answer Relatively level, aligning the lubber line with the center line of your body, locking your arms, and looking over the compass, not down on it How should I set a compass to navigate a straight line from one point to another? - correct answer 1. Hold the compass so the lubber line is pointed in desired travel direction
- Let the north needle settle on magnetic north, then rotate bezel until index marks straddle the needle
- Swim along the lubber line keeping the needle within the index marks
