Scuba

A depth change of 10 metres/33 feet causes a pressure change of

1 bar/ata

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

True

My buddy is rinsing a BCD and partially fills the bladder with water. Is this consistent with recommended BCD care?

yes

At 10 metres/33 feet you're _____ bar/ata of total pressure and the air density is ___ times as great as at the surface.

2

If you take 6 litres of air from the surface to 20 metres/66 feet, the volume will be _____ litres.

2

When choosing an alternate air source, a primary consideration involves deciding

between independence and simplicity

When scuba diving, normal breathing keeps your lungs equalized to the surrounding pressure.

true

Failure to follow the most important rule in scuba diving can cause severe lung overexpansion injuries, which can result in paralysis or death.

true Lung overexpansion injuries are among the worst injuries you can have in diving, and they are difficult to treat. But, they are also easy to avoid - never hold your breath while scuba diving.

To control my buoyancy, normally I will use my weight system and my

BCD

I should equalize

Before I feel pain or discomfort Equalize every metre/few feet, before you feel discomfort. If you wait until you feel discomfort, equalization may be difficult or impossible. When you equalize as often as you should, you don't feel discomfort or pain.

My mask encloses my nose so I can

Equalize the mask

Salt water causes more buoyancy than fresh water because it is less dense and weighs less.

False

There is no way to use a DIN regulator on a yoke cylinder valve.

False A common option is to choose a DIN regulator with a yoke adapter, useable on either type valve.

My SPG is always part of my dive computer.

False. Your SPG may be independent instrument or it may be integrated into your dive computer.

During a descent, I try to equalize but discover I'm having trouble doing so. Which of the following is correct?

If you can't equalize, stop your descent immediately. Signal your buddy(ies) or instructor. Ascend slightly until the discomfort passes and try again. If you still can't equalize, stop the dive. Continuing to descend with unequalized air spaces can lead to serious injuries!

The ____________ inflates the BCD with air from my scuba cylinder.

LPI mechanism

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.

Positively

Overall benefits of the buddy system include (choose all that apply):

Practicality, Safety, Fun

As I descend, I need to equalize air spaces. Which of the following are accepted ways of equalizing my ears? (choose all that apply)

To equalize your ears and sinuses, pinch your nose and blow gently against it. This sends air from your throat into your ears and sinuses. Some people find that wiggling their jaws side-to-side and swallowing also works. Do not use forceful or extended equalizations.

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

True

I must be able to quickly release enough weight to float reliably in an emergency, but not necessarily all my weight.

True

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

True

My BCD should have adequate capacity to easily float my equipment and me at the surface.

True

One reason for wearing more than one weight system is that it is sometimes easier than handling a single, heavier one.

True

A squeeze is caused by

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

I want to adjust my mask so the strap rests

above my ears, over the crown of my head

Equalization is the process of

adding air to an air space

The most important rule in scuba diving is to

breathe continuously and never hold your breath. If during ascent you hold your breath, blocking your airway, your lungs would over expand. Expanding air can cause serious lung overexpansion injuries. For this reason, the most important rule in scuba diving is to breathe continuously and never, ever hold your breath.

A balloon fully inflated and sealed at 10 metres/33 feet, would probably _______ during ascent to the surface.

burst

The ____________ is a safety device that relieves accidental overpressure by releasing air before reaching the pressure at which the cylinder would fail.

burst disk

Accessory weights

can help you adjust your trim

On a day I plan to go diving, I wake up with my sinuses blocked due to a cold or allergy. I should

cancel the dive until I am well

The three most important considerations in choosing scuba equipmentare suitability, fit and ____________.

comfort

When I descend, my buoyancy tends to _________. When I ascend, it tends to __________.

decrease, increase

Trim means having the right ________ of weight.

distribution

As I descend, increasing pressure affects my (choose all that apply):

ears, sinuses, mask

The three major body air spaces affected are:

ears, sinuses, mask

The most important consideration when choosing a regulator is

ease of breathing

Scuba cylinders require pressure testing __________ and visual inspection _________.

every 2-5 years, annually

A cylinder with a higher working pressure always holds more air than a cylinder with a lower working pressure.

false

From among masks that fit me, I should choose a mask that fits as far away from my face as possible.

false

My BCD should fit

fit snugly but not restrict breathing when fully inflated

An object that is neutrally buoyant in fresh water will _______ in salt water.

float

As you descend in water the pressure

increases

Underwater, when I inhale, my buoyancy

increases slightly

Before each use, I should__________________my equipment.

inspect

I need a mask because

my eyes must be in air to focus

I'm renting a scuba cylinder at a dive resort. Among the cylinders for hire, some have green and yellow bands that read "Nitrox." As a PADI Open Water Diver with no other training or instructor supervision, am I qualified to use one of these cylinders?

no

I should have my scuba cylinder filled

only by reputable scuba air stations

When my snorkel is in my mouth, the tip should be

over the crown of my head

The most important feature of my weight system is its

quick release

Identify the four systems that make up a scuba kit.

regulator, Cylinder, weight system, BCD

I bring a cylinder aboard a dive boat in preparation for a trip out to a nearby reef. The normal procedure would be to

secure the cylinder in a rack

When setting up and wearing my kit, the alternate air source

secures in the triangle formed by my hips and chin

My buddy and I are planning a dive to 18 metres/60 feet. We would expect our air supply to last ________ at 10 metres/33 feet, all else being the same.

shorter than. Because scuba delivers air at the surrounding pressure, the deeper your depth, the more air each breath takes from your cylinder. Therefore, the deeper you dive, the faster you use your air, all else being the same.

During a dive, I swim hard to keep up with a fish that interests me, but shortly begin to feel like I can't get enough air. The correct action would be to:

stop all activity and rest to restore proper deep, slow breathing. Avoid getting winded or out-of-breath underwater. If you're faced with a problem while diving, stop what you're doing, then reduce anxiety by maintaining or restoring slow, deep breathing as you handle it.

I'm descending and discover I can't equalize. The first thing I would do is

stop my descent and signal my buddy/the instructor

During ascent I feel discomfort in my ears. I should

stop, descend slightly and allow trapped air to work its way out. If you feel discomfort in any air space during ascent, immediately slow or stop your ascent. Descend a metre/few feet to reduce the discomfort and give the trapped air time to work its way out. Ascend more slowly, giving the expanding gas time to exit.

The density of the air in the previous question would be ________ the density at the surface.

three times

Getting the service my gear needs may be a consideration when choosing equipment.

true

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

true

My local dive pro will usually set up my regulator components.

true

Regulators need periodic overhauls, typically every year to two years.

true

Snorkels are standard equipment for scuba diving because they allow me to breathe with my face in the water, or in rough conditions, without wasting my scuba air, especially when I have little scuba air remaining.

true

Some scuba divers prefer a snorkel with a flexible lower portion so it drops out of the way when not in use.

true