PADI Open Water - Being a Diver I

ears, sinuses, and mask

What three major body air spaces does increasing pressure affect as I descend?

b. burst

A balloon fully inflated and sealed at 10 metres/33 feet, would probably __________ during ascent to the surface. a. shrink (become smaller) b. burst

a. 1 bar/ata

A depth change of 10 metres/33 feet causes a pressure change of... a. 1 bar/ata b. 2 bar/ata c. 3 bar/ata d. 4 bar/ata

b. a pressure imbalance between the surrounding pressure and an air space

A squeeze is caused by... a. wearing my wet suit or other gear too tightly b. a pressure imbalance between the surrounding pressure and an air space

a. mask b. ears c. sinuses

As I descend, increasing pressure affects my (choose all the apply)... a. mask b. ears c. sinuses d. skin

b. 18 metres/60 feet

As a newly certified PADI Open Water Diver, I will be trained to dive with a buddy as deep as __________. a. 10 metres/30 feet b. 18 metres/60 feet c. 30 metres/100 feet d. 40 metres/130 feet

a. increases

As you descend in water the pressure... a. increases b. decreases c. does not change

1 bar/ata

At 0 metres/feet (sea level), what is the total pressure?

2 bar/ata — one of air plus one of water

At 10 metres/33 feet, what is the total pressure?

3 bar/ata — one of air plus two of water

At 20 metres/66 feet, what is the total pressure?

4 bar/ata

At 30 metres/99 feet, what is the total pressure?

one bar (metric) or one atmosphere (imperial — abbreviated ata)

At sea level the pressure is fairly uniform, and is expressed as...

a. true

Buoyancy is a force that pushes an object in water upward. a. true b. false

A given volume weighs more in salt water than in fresh water, because salt water has dissolved minerals (salt) in it. Salt water causes more buoyancy (more upward force) than fresh water, because salt water weighs more.

Does a given volume weigh more in salt water or fresh water? Why? Does salt water or fresh water cause more buoyancy? Why?

b. stop, descend slightly and allow trapped air to work its way out

During ascent I feel discomfort in my ears. I should... a. continue my ascent at a slightly faster rate b. stop, descend slightly and allow trapped air to work its way out c. use a decongestant before my next dive d. equalize by blowing gently against blocked nostrils

a. adding air to an air space

Equalization is the process of... a. adding air to an air space b. removing air from an air space c. reducing the surrounding pressure d. increasing the surrounding pressure

a. true

Failure to complete assigned independent study can create significant delays, and my instructor may have to cancel and reschedule sessions until I complete the assignment. a. true b. false

a. true

Failure to follow the most important rule in scuba diving can cause severe lung over expansion injuries, which can result in paralysis or death. a. true b. false

Because scuba provides air at the surrounding pressure, as you go deeper each breath takes more air from your scuba cylinder. Therefore, the deeper you are, the faster you use your air.

How does depth affect how long my air supply lasts?

Pressure decreases one bar/ata for every 10 metres/33 feet you ascend (come up).

How does pressure decrease underwater?

Pressure increases by one bar/ata for each 10 metres/33 feet you descend (go down).

How does pressure increase underwater?

a. true

My body responds to anxiety with increased breathing, but slow breathing helps reduce anxiety. a. true b. false

c. cancel the dive until I'm well

On a day I plan to go diving, I wake up with my sinuses blocked due to a cold or allergy, I should... a. take an approved decongestant so I will be able to equalize b. plan to take a lot longer as I descend c. cancel the dive until I'm well

a. practicality b. safety c. fun

Overall benefits of the buddy system include (choose all that apply): a. practicality b. safety c. fun

a. meet specific performance requirements

PADI courses are performance-based. This means that to be certified, I must... a. meet specific performance requirements b. spend a given number of hours in training c. simply pay for the course

A gas volume decreases because the gas molecules get compressed. Gas density increases because all the molecules are there, but they're packed into a smaller area.

Pressure changes affect the volume and density of air (or any other gas). As the pressure increases — as you go deeper — why does a gas volume decrease? Why does gas density increase?

weight

Right now, you are under pressure exerted by the air in the atmosphere that surrounds you. This is actually the __________ of the air.

b. false

Salt water causes more buoyancy than fresh water because it is less dense and weighs less. a. true b. false

The balloon expands, growing larger until it stretches past its failure point and bursts. To prevent this, you'd leave the balloon unsealed and vent some of the expanding air as you ascend.

Suppose you fill a balloon completely and seal it at 10 metres/33 feet. What happens as you ascend? How would you prevent this?

plan your dives together, help each other gear up and check each other's equipment, remind each other of dive time and depth limits, assist each other if there's a problem, and assist each other with what each wants to do on the dive

The buddy system is so integral to recreational diving that your training includes it from the start. List five things that you and your buddy will do.

c. three times

The density of air in the previous question would be __________ the density at the surface. a. one-third b. one-half c. three times d. four times

c. deeply and slowly

The most efficient way to breath dense air underwater is to breathe... a. shallowly and slowly b. shallowly and rapidly c. deeply and slowly d. deeply and rapidly

b. breathe continuously and never hold your breath

The most important rule in scuba diving is to... a. always dive with a buddy b. breathe continuously and never hold your breath c. check your air supply every 5 minutes

d. BCD

To control my buoyancy, normally I will use my weight system and my... a. fins b. scuba cylinder c. wet suit d. BCD

b. increases slightly

Underwater, when I inhale, my buoyancy... a. decreases slightly b. increases slightly c. doesn't change

weight

Underwater, you're under more pressure because water also has __________, which combines with the atmosphere's pressure.

Expanding air can cause serious lung over expansion (lung rupture) injuries that are difficult to treat and can cause paralysis and death by forcing air into the bloodstream and chest cavities.

What can happen if I don't follow the most important rule in scuba diving?

your weight system and your BCD or Buoyancy Control Device

What two pieces of equipment do I normally use to control buoyancy?

10 metres/33 feet

Because water is much denser and heavier than air, __________ feet exerts the same pressure as the whole atmosphere.

a. true

Certain medical conditions can be hazardous while diving, so it is important to answer all questions on the Medical Statement honestly and completely. a. true b. false

A squeeze can occur if you don't adjust for increasing pressure compressing a body air space. A squeeze causes discomfort, and if not corrected can cause injury by pressure imbalance that pushes tissues into an air space. This happens because there is greater pressure outside the air space than inside it.

How can a squeeze occur? What does a squeeze cause, and what can it lead to if not corrected? Why does this happen?

Slow, deep breathing will help you to reduce stress and anxiety.

How do I breathe to reduce anxiety when under stress?

When you inhale, your chest expands, increasing your volume, displacement, and buoyancy. When you exhale, you contract your chest, decreasing your volume, displacement, and buoyancy.

How does breathing affect my buoyancy?

When you descend, volume decreases, which reduces water displaced and reduces your buoyancy making you more negatively buoyant. You offset this by adding air to your Buoyancy Control Device. When you ascend, the gas volume in your gear re-expands, which increases your buoyancy. The air you added to your BCD also expands and further increases your buoyancy. To control your buoyancy, as you ascend you vent (release) the air you added on the way down.

How does descending affect your buoyancy? How do you offset this? How does ascending affect your buoyancy? What happens to the air you aded to your BCD? How do you control this?

You should equalize every metre/few feet before you feel discomfort or pain. To equalize your ears and sinuses, pinch your nose and blow gently against it, which sends air from your throat into your ears and sinuses. To equalize your mask, blow air into it through your nose as you descend.

How often should I equalize? How do you equalize your ears and sinuses? How do you equalize your mask?

a. true

I equalize gently because an extended, forceful equalization can cause permanent damage to my ears and hearing. a. true b. false

c. before I feel pain or discomfort

I should equalize... a. when I feel pain or discomfort b. only if I can't tolerate the pain or discomfort c. before I feel pain or discomfort d. when I reach the bottom

b. stop my descent and signal my buddy/the instructor

I'm descending and discover I can't equalize. The first thing I would do is... a. equalize more forcefully b. stop my descent and signal my buddy/the instructor c. slow my descent and see if the problem corrects itself

Your air volume decreases by 1/3 the surface volume, and your air density will be 3 times the surface density.

If you go from 10 metres/33 feet to 20 metres/66 feet, what happens to your air volume and air density?

Your air volume decreases by 1/4 the surface volume, and your air density will be 4 times the surface density.

If you go from 20 metres/66 feet to 30 metres/99 feet, what happens to your air volume and air density?

Your air volume decreases by 1/5 the surface volume, and your air density increases by 5 times the surface density.

If you go from 30 metres/99 feet to 40 metres/132 feet, what happens to your air volume and air density?

Your air volume decreases by 1/2, and your air density will be doubled.

If you go from the surface to 10 metres/33 feet, what happens to your air volume and air density?

b. 2

If you take 6 litres of air from the surface to 20 metres/66 feet, the volume will be __________ litres. a. 1 b. 2 c. 3 d. 4

a. true

In recreational diving, the buddy system means diving with another diver or divers in a team that provides assistance and safety benefits. a. true b. false

a. true

It is important to master buoyancy control because it affects almost everything I do in and underwater. a. true b. false

descend and ascend at a slow, controlled rate; stop a descent or ascent and maintain your depth with little effort; float comfortably on the surface; save energy and avoid harming sensitive aquatic organisms by swimming neutrally buoyant and controlling your movements; maintain the underwater visibility by helping you not stir up the bottom; enjoy the "weightlessness" sensation that is unique to diving.

List six things that buoyancy control allows you to do.

c. faster than

My buddy and I descend to 12 metres/40 feet. I would expect to use my air __________ at 6 metres/20 feet. a. slower than b. at the same rate as c. faster than

a. positively

My sunglasses case falls out of my pocket into the water, but fortunately, it floats so I retrieve it. I would say my sunglasses case is __________ buoyant. a. positively b. negatively c. neutrally

1. Breathe continuously and never ever hold your breath. 2. Breathe slowly and deeply. 3. Do not allow yourself to get winded or out of breath. 4. If faced with a problem, stop, then reduce anxiety by maintaining or restoring slow, deep breathing.

What are my four breathing rules as a scuba diver?

Positive buoyancy, which occurs when an object weighs less than the water it displaces and the object floats. Negative buoyancy, which occurs when an object weighs more than the water it displaces and the object sinks. Neutral buoyancy, which occurs when an object weighs the same as the water it displaces and the object neither floats nor sinks.

What are the three types of buoyancy? Describe them.

Practicality - you assist each other before, during, and after the dive. Safety - you help each other prevent problems, and you assist each other if there is an emergency. Fun - diving is a social activity; it's rewarding and fun to have someone to share underwater adventures.

What are three overall benefits of the buddy system?

Your weight system holds just enough lead weight to offset your positive buoyancy. You need this because most people float, and some of your gear also floats. How much weight you need depends upon your gear, your physical characteristics, and whether you're diving in fresh or salt water. Use just enough weight to allow you to descend, but you shouldn't sink rapidly.

What does your weight system hold? Why do you need this? How much weight should you use?

A reverse block, also called a reverse squeeze, results when expanding air becomes trapped in a body air space.

What is a "reverse block"?

Buoyancy is an upward force acting on an object in water, which is why you feel "lighter" in water. This force is caused by the water displaced (pushed aside) by the object, and is equal to the weight of the water displaced.

What is buoyancy? What causes it?

The buddy system is diving with another diver or divers in a team that provides shared assistance and safety benefits.

What is the buddy system?

The most important rule in scuba diving is to breathe continuously and never ever hold your breath.

What is the most important rule in scuba diving?

There is a pressure change of 1 bar/ata for every 10 metres/33 feet of depth change.

What is the pressure change for each 10 metres/33 feet of depth change?

As depth in water increases, pressure increases. As depth in water decreases, pressure decreases.

What is the relationship between my depth in water and the pressure?

As pressure increases, gas volume decreases and gas density increases.

What is the relationship between pressure and the volume and density of air?

Adding air to the air spaces as you descend in order to keep their pressure equal with the outside pressure, so they stay at their normal volume.

What it "equalization"?

Increasing pressure may affect other body air spaces as you descend. It's very rare, but an air space can develop in filled teeth and cause discomfort. If this happens, stop your descent because you can't equalize this air space. See your dentist to correct the air space.

What other body air spaces are affected by increasing pressure? How do I equalize them?

To change your buoyancy during a dive, you use your BCD or Buoyancy Control Device. Inflating and deflating it increases and decreases your volume or how much water you displace. This adjusts your buoyancy so you can be positively, negatively, or neutrally buoyant when you want.

What piece of equipment will you use to change your buoyancy during a dive? What does inflating and deflating it do? What does this adjust?

If you can't equalize, stop your descent immediately. Signal "problem" to your friends or instructor and point to your ear. Ascend slightly until the discomfort passes and try again. After you equalize, descend more slowly, equalizing more frequently. If you still can't equalize, stop the dive.

What should I do if I can't equalize? What can happen if I don't or can't equalize and keep descending?

Immediately slow or stop your ascent. Descend a meter/few feet to reduce the discomfort and give the trapped air time to work its way out.

What should I do if I feel discomfort in my ears, sinuses, stomach, intestines, or teeth while ascending?

The most efficient way to breathe dense air underwater is by taking slow, deep breaths. Pace yourself and dive relaxed in order to save energy and prevent over exertion.

What's the most efficient way to breathe dense air underwater?

c. decrease, increase

When I descend, my buoyancy tends to __________. When I ascend, it tends to __________. a. increase, increase b. increase, decrease c. decrease, increase d. decrease, decrease

a. true

When diving in a new dive environment, two benefits of seeking an orientation, supervision, and/or additional training are that it helps me avoid problems and that it helps me enjoy the dive more. a. true b. false

a. true

When scuba diving, normal breathing keeps your lungs equalized to the normal pressure. a. true b. false

a. Breathe continuously and never ever hold my breath. b. Breathe slowly and deeply. c. Do not allow myself to get winded or out-of-breath. d. If faced with a problem, stop, then maintain or restore slow, deep breathing.

Which of the following are among the breathing rules I follow as a diver? (Choose all that apply.) a. Breathe continuously and never ever hold my breath. b. Breathe slowly and deeply. c. Do not allow myself to get winded or out-of-breath. d. If faced with a problem, stop, then maintain or restore slow, deep breathing.

You use your Buoyancy Control Device frequently because your buoyancy tends to change when you change depth.

Why do you use your BCD frequently?

Congestion from a cold or allergy can block normal air flow and may make equalization of body air passages difficult or impossible. Earplugs create air spaces that you can't equalize.

Why does congestion from a cold or allergy temporarily keep me from diving? Why should I never dive with earplugs?

It is important to master buoyancy control because it affects almost everything you do in and underwater.

Why is it important to master buoyancy control?

A forceful, extended equalization can cause serious permanent injuries to your ears and hearing.

Why should I equalize gently?