PADI Open Water Diver Certification 167 Questions and Answers, Exams of Biology

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PADI Open Water Diver Certification 167

Questions and Answers

SCUBA -

✔Self contained underwater breathing apparatus What is the pressure change for each 10m/33ft of depth change? - ✔1 bar/1 ata/1 atmosphere What is the relationship between my depth in water and the pressure? - ✔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? - ✔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? - ✔Volume will be 1/ata# Density will be ata# What 3 major body air spaces does increasing pressure affect as I descend? - ✔Ears, sinuses, mask What is a "squeeze"? - ✔The discomfort caused by pressure imbalance pulling tissue into the air space What is "equalization"? - ✔The addition of air to your air spaces as you descend

How do I equalize as I descend? - ✔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? - ✔Every meter/few feet, BEFORE you feel discomfort What should I do if I can't equalize? - ✔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? - ✔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? - ✔Congestion might block normal air flow, making equalization difficult or impossible Why should I never dive with earplugs? - ✔They create air spaces that you can't equalize What other body air spaces are affected by increasing pressure? How do I equalize them? - ✔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? - ✔Breathe continuously and never hold your breath What can happen if I don't follow the most important rule in scuba diving? - ✔Your lungs will over expand and rupture

What is a "reverse block"? - ✔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? - ✔Stop your ascent and descend a meter/few feet to reduce discomfort and give trapped air time to work its way out How does depth affect how long my air supply lasts? - ✔The deeper you are, the more dense air you breathe, and the faster you use the air in your cylinder. Compared to the surface, air supply lasts 1/#ata as long along with other factors What's the most efficient way to breathe dense air underwater? - ✔Take slow, deep breaths How do I breathe to reduce anxiety when under stress? - ✔Do NOT breathe faster - keep breathing slowly What are my 4 breathing rules as a scuba diver? - ✔1. Breathe continuously and never hold your breath

2. Breathe slowly and deeply
3. Don't allow yourself to get winded or out of breath
4. If faced with a problem, stop, and reduce anxiety by breathing slowly and deeply What is buoyancy? - ✔An upward force acting on an object in the water, canceling the pull of gravity What causes buoyancy? - ✔The upwards force is caused by the water displaced by the object, and is equal to the weight of displaced water positive buoyancy -

✔The object weighs less than the water it displaces, so it floats neutral buoyancy - ✔The object weighs the same as the water it displaces, neither sinking nor floating negative buoyancy - ✔The object weighs more than the water it displaces, so it sinks Why does salt water cause more buoyancy than fresh water? - ✔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? - ✔The weight system and the BCD (buoyancy control device) How does descending affect my buoyancy? - ✔The volume decreases, reducing buoyancy, so you ADD air to the BC How does ascending affect my buoyancy? - ✔The volume increases, adding buoyancy, so you RELEASE air from the BC How does breathing affect my buoyancy? - ✔Inhaling adds, exhaling reduces What is the buddy system? - ✔Diving with another diver What are the 3 most important considerations in choosing scuba equipment? - ✔Suitability, fit, and comfort How do I generally care for scuba equipment? - ✔Rinse everything in fresh water and dry it in the shade and store in a cool, dry place

Why do I need a mask? - ✔It provides an air space so your eyes can focus because light behaves differently underwater Why does my mask need to enclose my nose? - ✔Because the mask creates an air space, you need your nose to blow in it to equalize it Why do I need a snorkel? - ✔It saves your air supply while your face is in the water What are 2 basic fin styles? - ✔Full-foot and adjustable strap What consists of your scuba kit? - ✔Buoyancy control device, regulator, air cylinder, weight system What 5 components make up a BCD? - ✔Inflatable bladder, harness/jacket and cylinder band, low pressure inflator (LPI) mechanism, overpressure/quick dump exhaust valve, weight system inflatable bladder - ✔Controls buoyancy harness/jacket and cylinder band - ✔Holds cylinder on back low pressure inflator (LPI) mechanism - ✔Inflates bladder with air from your cylinder with the touch of a button overpressure/quick dump exhaust valve - ✔Vents air if the bladder is overfilled

weight system - ✔Contain weight pockets that you release and drop in case of emergency What 2 special maintenance considerations do BCDs have? - ✔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? - ✔First stage, second stage, alternate air source, low pressure inflator (LPI) hose, submersible pressure gauge (SPG) first stage - ✔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) alternate air source - ✔An extra second stage you use for sharing air with a buddy Attaches in triangle area between chin and hips second stage - ✔Reduces pressure to surrounding pressure, delivers air upon inhalation, vents exhalation Goes over right shoulder low pressure inflator (LPI) hose - ✔Supplies air to your BCD inflator submersible pressure gauge (SPG) - ✔Hose that tells you air pressure remaining in your cylinder Goes under left arm What is the most important consideration in choosing a regulator? -

✔The ease of breathing yoke system - ✔Holds first stage to cylinder with a clamp DIN system - ✔Regulator screws into valve What 3 special maintenance considerations do regulators have? - ✔Rinse first stage individually, run water through second stage, have professional overhaul it about every year What 2 components make up a scuba cylinder? - ✔The aluminum/steel container and the valve to control air flow What is a burst disk? - ✔A safety device that relieves overpressure by rupturing and releasing air What is the most important feature in my weight system? - ✔A quick release that will enable you to float with an uninflated BC Why use more than 1 weight system? - ✔It will help distribute weight trim - ✔The orientation and balance of a swimmer in the water - the ideal is horizontal danger/hazard - ✔ okay -

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go up/end dive - ✔ something's wrong - ✔ down/descend - ✔ low on air - ✔ okay - ✔ distress/in trouble - ✔ How does being underwater affect the apparent size or distance of things? - ✔Refraction occurs, where light changes direction, and things are magnified by 1/ How does water affect light intensity and color? - ✔It reflects, scatters, and absorbs light in the roygbiv order As you go deeper, it gets darker How does hearing differ underwater? - ✔It travels faster and longer How does water's density affect moving in water? -

✔It takes more energy the faster you try to swim What is "airway control"? - ✔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? - ✔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? - ✔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? - ✔Stop all activity, signal your buddy, and rest What points should a dive plan normally include? - ✔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? - ✔Using Begin With Review And Friend (BWRAF) BWRAF - ✔BCD, weight, releases, air, final check What do I do if I get separated from my buddy on a dive? - ✔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? -

✔Plan your dive around who breathes air the fastest. Subtract your reserve/ascent supply from your starting pressure to find out how much pressure you have for the main part of the dive To be safe, plan to use half your air coming down, and half coming back What are the 5 steps for a proper descent with scuba? - ✔1. Confirm that your buddy is ready

2. Orient yourself to something
3. Switch from your snorkel to your regulator
4. Check your dive computer/timer
5. Signal "descend" and slowly deflate your BCD What are the 5 steps for a proper ascent with scuba? - ✔1. Signal "up" and confirm that your buddy is ready
6. Check your dive computer/timer to be sure you're within dive limits
7. Look up and hold your BCD deflator hose
8. Ascend no slower than your dive computer's maximum rate
9. Look up, turn as you ascend, and stay with your buddy What is the maximum ascent rate? - ✔18 m/60 ft//min What is a safety stop? - ✔A pause in your ascent between 6 m/20 ft and 3 m/10 ft to give your tissues extra time to release dissolved gases for at least 3 minutes When would I not make a safety stop? - ✔When you're assisting a diver who has an air supply problem or if you're low on air dive computer - ✔Tells you your time and depth underwater and guides you in keeping dissolved nitrogen in your body within accepted limits

How do I measure/define visibility as a diver? - ✔The distance you can see horizontally underwater What 4 principles affect visibility? - ✔Water movement, weather, plankton, bottom composition When diving in a mild current, in what direction would I normally go? - ✔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? - ✔Swim perpendicular to the current What two things in the water affect a diver? - ✔The waves and current What is assessing conditions based on? - ✔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? - ✔Remain still and calm. Swim away if you become uncomfortable In what depth water do waves break? - ✔In the surf zone, in water only slightly deeper than their height surge - ✔A back-and-forth motion caused by waves passing overhead undertow -

✔The water of waves flowing back to sea under incoming waves rip current - ✔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? - ✔Establish buoyancy and swim at a sustainable pace parallel to the shore upwelling - ✔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? - ✔The current, depth, and visibility bow - ✔The front of the boat stern - ✔The back of the boat port - ✔The left side of the boat as you face forward starboard - ✔The right side of the boat as you face forward leeward - ✔The side away from the wind windward -

✔The side toward the wind The bridge/wheelhouse - ✔The portion of the boat where the controls are head - ✔The boat's toilet facilities galley - ✔The boat's kitchen area swim step - ✔A platform on the stern that is close to water level What are characteristics of a responsive diver? - ✔They are breathing, alert, and active What are the 4 basic steps for assisting a responsive diver at the surface? - ✔1. Help reestablish breathing control

2. Have the diver take slow, deep, breaths
3. Give the diver a chance to rest and recover
4. Assist the diver to the boat or shore What are the 4 basic steps for assisting an unresponsive diver at the surface? - ✔1. Establish buoyancy for the victim and yourself
5. Call for help
6. Check for breathing and begin rescue breaths as you tow the diver
7. Continue rescue breathing and get the victim out of water How should I breathe from a freeflowing regulator? -

✔DON'T seal your mouth on the mouthpiece. Hold the second stage and press the mouthpiece outside your lips, or insert one end of the mouthpiece into your mouth and "sip" breaths. Begin ascent immediately In order of priority, what are my four options if I run out of air underwater? - ✔1. Take lighter breaths and don't attempt a safety stop as you ascend

2. Use an alternate air source from your buddy
3. Make a controlled emergency swimming ascent (CESA)
4. Make a buoyant emergency ascent How do I make a controlled emergency swimming ascent (CESA)? - ✔When you have no air and are approximately 6-9 m/20-30 ft from the surface, look up and swim to the surface making a continuous ahhhhh sound into your regulator How do I make a buoyant emergency ascent? - ✔When you have no air and are very deep, ditch your weights, look up and swim to the surface making a continuous ahhhhh sound into your regulator How should I assist an unresponsive diver underwater and what is the priority? - ✔You want to get the diver to the surface. Hold the diver's regulator in their mouth and try to ascend at a safe rate At a minimum, how many surface signaling devices should I have with me on a dive? - ✔At least 2 - one audible and one visual How close am I supposed to stay to a dive flag? - ✔Within 15 m/50 ft How far away are boaters supposed to stay from a dive flag? - ✔At least 30-60 m/100-200 ft For what 4 purposes might I carry a slate or wet book? -

✔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? - ✔Date, dive site name/location, dive buddy, dive depth and duration, objective and description What can I do with dive planning software? - ✔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? - ✔79% nitrogen and 21% oxygen To what 4 diving related issues does the makeup of air relate? - ✔Oxygen toxicity, contaminated air, decompression sickness, and gas narcosis How do I prevent oxygen toxicity? - ✔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? - ✔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? - ✔Depth and time What is decompression sickness (DCS), or "the bends"? - ✔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? - ✔Paralysis, dizziness, tingling, joint and limb pain, shock, numbness, difficulty breathing, weakness and prolonged fatigue, unconsciousness and death When do symptoms of DCS occur? - ✔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? - ✔By using your dive time and depth information to calculate the theoretical amount of nitrogen in your body What is no stop diving? - ✔When you can swim directly to the surface without unacceptable risk of decompression sickness What is a no stop limit? - ✔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? - ✔I must make an emergency decompression stop What is an emergency decompression stop? - ✔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? - ✔The deeper you dive, the shorter your no stop limits What is the difference between a decompression stop and a safety stop? - ✔Safety stops keep you well within limits, whereas emergency decompression stops return you from outside limits Why is residual nitrogen important? -

✔It shortens your no stop limits if you make another dive What is a repetitive dive? - ✔A dive made while you still have residual nitrogen How do dive tables work? - ✔Table 1 assigns a Pressure Group letter that represents the theoretical amount of residual nitrogen based on your dive time and depth. Table 2 gives you credit for nitrogen leaving your body during a surface interval. Table 3 provides reduced no stop times for a repetitive dive What is a surface interval? - ✔The time you spend at the surface between dives. During this, the residual nitrogen declines as it dissolves How do I be a SAFE diver? - ✔You slowly ascend from every dive What is finding a minimum surface interval? - ✔Determining how long to wait after the first dive to have the no stop time you want at the planned depth of the repetitive dive What relationship is shown through dive computers? - ✔Depth and no stop time What are 3 ways I can find a minimum surface interval with a dive computer without using dive tables? - ✔Wait and check your no stop time until it matches your planned repetitive dive depth, use the dive computer's plan mode, or use a tablet or smart phone app Why is going to a higher altitude after diving a potential issue? - ✔It lowers the pressure around you at the surface, so dissolved nitrogen in body tissues comes out of solution faster than at sea level, therefore increasing your risk of DCS

How do you fly or ascend to altitude after diving? - ✔You start and end your dive at sea level, and then go to lower surface pressure at altitude How do you altitude dive? - ✔You start and end your dive at lower surface pressure at altitude What are the current recommendations for flying after a single dive? - ✔A minimum surface interval of 12 hours What are the current recommendations for flying after repetitive dives or multiday dives? - ✔A minimum surface interval of 18 hours What are the current recommendations for flying after dives requiring emergency decompression stops? - ✔A minimum surface interval greater than 18 hours Why are being cold and/or exerting myself strenuously issues with respect to decompression sickness risk? - ✔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? - ✔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? - ✔1. Stop all diving

2. Check for breathing and provide CPR as needed
3. Contact emergency medical care
4. Keep the diver lying down and provide emergency oxygen
5. Monitor the diver and take steps to prevent shock
6. Lay the diver level, left side down, head supported, breathing oxygen What treatment is usually required for DCI? -

✔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? - ✔An intoxicating effect when many gases are put under pressure What are signs/symptoms of gas narcosis? - ✔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? - ✔Don't dive too deep and immediately ascend to a shallower depth What is a lubber line on a compass? - ✔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? - ✔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? - ✔1. Hold the compass so the lubber line is pointed in desired travel direction

2. Let the north needle settle on magnetic north, then rotate bezel until index marks straddle the needle
3. Swim along the lubber line keeping the needle within the index marks