PADI Open Water Diver Certification Verified Questions And Answers

PADI Open Water Diver Certification Verified 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 - 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 1/3 How does water affect light intensity and color? - It reflects, scatters, and absorbs light in the roygbiv order