SDI final review

Which of the following is not true? Divers should equalize:

As soon as they feel any pain or discomfort.

If symptoms such as euphoria, anxiety or motor skill impairment make you suspect you are suffering from narcosis, the best response is to:

Ascend to a depth at which the symptoms disappear.

The most accurate place to conduct a weight check is:

At safety-stop depth, at the end of the dive.

Which of the following is the best way to prevent or reduce nitrogen narcosis?

Avoid dives below 20 meters/66 feet.

All of the following can help prevent decompression sickness (DCS) except:

Avoid drinking fluids prior to the dive.

To be injured by an animal with poisonous spines, you must:

Be the aggressor and touch the animal first.

Before adding air to your BC under water, you must:

Be thoroughly familiar with the location and operation of your BC's inflation/deflation mechanism(s). Empty your lungs so that they do not affect your overall buoyancy. Be ready to instantly vent air from you BC, should you accidentally add too much. Both the first and third answers are correct.

The single most important rule of scuba diving is:

Breathe continuously; never hold your breath.

The key to using air efficiently while breathing from scuba is to:

Breathe slowly and deeply.

Which of the following may indicate that air in a scuba cylinder is contaminated and potentially toxic?

Color. Odor. Taste. Any of the above.

As you descend:

Colors appear to fade. Reds and oranges are among the first colors to disappear. At 30 m/99 ft, little color remains other than blues, grays, blacks and whites. All of the above.

Among the most important features to look for when selecting fins are:

Comfort and fit. Blade size proportional to leg strength. Suitability for the type of diving you do. All of the above.

Among the reasons divers prefer computers over dive tables:

Computers account for the multilevel nature of most dives and, therefore, allow longer no-decompression limits. Computers are generally more convenient to use than dive tables. Computers provide among the best possible means of keeping ascent rates under control. All of the above.

The primary function of a mask is to:

Create an air space in front of the eyes, enabling them to focus.

Air passages such as your trachea (windpipe), which may contain air your body can't use, are known as:

Dead air spaces.

Steps in equipment assembly include all of the following except:

Depressurize system and test regulators.

Common exposure suit types include:

Dive skins. Wet suits. Dry suits. All of the above.

Not allowing alternate-air-source second stages, instrument consoles and other equipment to dangle freely:

Does little to protect equipment from damage. Helps protect equipment from damage. Helps reduce the risk of entanglement. Both the second and third answers are correct.

If you will be rinsing your regulator after removing it from the cylinder, you must make sure that the ______ ______ is firmly in place.

Dust cap

Any time a regulator is out of your mouth under water, you should:

Exhale a small, steady stream of bubbles.

Common methods for clearing water from a regulator second stage include:

Exhaling into the second stage. Holding the second stage over your head with the mouthpiece pointed down. Depressing the purge button. Both the first and third answers are correct.

A dive knife or cutting tool can be used to:

Fend off dangerous aquatic life. Help free an entangled diver. Signal others under water by using it to bang on a cylinder. Both the second and third answers are correct.

The type of kick most commonly used by recreational divers is the:

Frog kick. Dolphin kick. Bicycle kick. None of the above.

The types of fins commonly used by recreational scuba divers include:

Full-foot fins. Detachable-blade fins. Open-heel/adjustable fins. Both the first and third answers are correct.

Which is the most common boat entry technique for deep water entry on large dive boats?

Giant stride.

Your body loses the greatest amount of heat through the:

Head.

When pressurizing your scuba system (i.e., turning the air on), you should:

Hold the SPG facing down or away from you.

Scuba cylinders must be:

Hydrostatically tested and visually inspected at intervals determined by local laws and regulations, or prevailing standards of practice.

Which of the following is/are true?

If caught in a rip current, swim parallel to shore, until you are completely out of the rip current, then swim in towards shore.

Which of the following is not true?

If the bottom of a wave moves faster than the top, the wave will break.

Treatment of DCS may involve:

In-water recompression. Administration of pure oxygen. Recompression in a hyperbaric chamber. Both the second and third answers are correct.

After exhaling to clear water from your second stage, you should:

Inhale cautiously, so that you can 'breathe past" any remaining water.

The best type of boat entry:

Is a backward roll. Is the one the crew recommends. Is generally the easiest. Both the second and third answers are correct.

The backward roll:

Is chiefly a small-boat entry.

Surge

Is the back-and-forth movement of water caused by waves passing over head.

Because sound travels faster under water:

It is harder to determine the direction from which a sound is coming.

Popular BC styles include:

Jacket-style (wraparound). Horse-collar style. Back-inflation style. Both the first and third answers are correct.

Among the key points in doing a flutter kick correctly:

Keep your knees as straight as possible. Emulate the leg movements you make when pedaling a bicycle. Keep your toes pointed. Both the first and third answers are correct.

Key points in recovering a second stage using the sweep method include:

Lean towards your right and dip your right shoulder.

Which of the following is not true?

Longshore currents always move in the same direction.

In general, you want to enter the water with your BC:

Partially inflated.

_________ buoyant items tend to float; __________ buoyant items tend to sink; items that are __________ buoyant neither float nor sink.

Positively, negatively, neutrally

Having just enough weight to achieve all three states of buoyancy with only minor adjustments in the water is the definition of:

Proper weighting.

Which of the following is not true? When Clearing a mask, you should:

Pull out slightly at the base of the mask to create a space for water to exit.

Contributing factors to decompression sickness can include:

Rapid ascents. 'Pushing" or exceeding your computer's no-decompression limits. Heavy exertion and/or dehydration. All of the above.

The two most common methods for recovering a regulator that has fallen behind your shoulder are:

Reach, Sweep

Basic post-dive equipment maintenance and care includes:

Rinsing thoroughly with fresh water. Allowing to dry completely. Storing in a cool, dry place, away from direct sunlight. All of the above.

Rinsing equipment in fresh water helps remove:

Salt. Chlorine. Sand, mud and other sediments. All of the above.

Only a truly redundant alternate air source, such as a pony/bail-out bottle, can be used for:

Self rescue.

A mask must cover the nose:

So that you can keep the pressure inside the mask equal to the pressure outside.

If possible, before attaching your BC to your scuba cylinder, you should:

Soak the cam band (tank band) in water.

Desirable mask features include:

Soft, silicone skirt. Low internal volume. Snug, comfortable fit. All of the above.

Which of the following is/are true?

Surge is the back-and-forth movement of water caused by waves passing over head.

After your buddy checks to see that your air is turned all the way on:

Take several deep breaths from your regulator while watching your SPG for changes in pressure.

To successfully vent air from a BC:

The exhaust valve you will be using must be the highest point on the air cell.

An ear squeeze occurs when:

The pressure inside the middle ear space is less than ambient (surrounding) pressure.

What is/are the primary cause(s) of permanent ocean currents?

The sun warming equatorial ocean water. Seismic activity deep under water. The earth's rotation. Both the first and third answers are correct.

When water stratifies itself into layers, according to temperature, the boundary between layers is known as a(n):

Thermocline

In recent years, integrated weight BCs have overtaken conventional weight belts in popularity among divers because:

They are generally more comfortable to wear. They are generally easier and more convenient to use. They give divers the option to drop just a portion of their weight, if needed. All of the above.

Among the limitations of full foot fins:

They are not well suited for colder-water diving. There are no full-foot fins sufficiently powerful for use with scuba equipment. They are not well suited for entries from rocky shores. Both the first and third answers are correct.

Which of the following is/are true?

Tidal currents can be very strong, making diving difficult or even dangerous.

Which of the following is/are true?

Tides can make the water at a particular dive site noticeably deeper or shallower than you may have experienced previously. Tidal currents can be very strong, making diving difficult or even dangerous. Strong tidal currents can have an adverse effect on visibility. All of the above.

Among the key points in using your BC to help maintain neutral buoyancy under water:

To be successful in maintaining neutral buoyancy, you must be: aware of changes in depth; and, anticipate the need to add or vent air from your BC by keeping a hand on the inflator.

Before you can remove the regulator from your scuba cylinder, you must:

Turn the air all the way off. Depressurize the system by depressing and holding one of the purge buttons. Make sure the low-pressure inflator hose remains connected to the BC power inflator. Both the first and second answers are correct

The key to venting a BC, at the surface or under water, is to:

Turn your body so the the exhaust valve is the highest point on the BC air cell.

Which of the following is/are true?

Water conducts heat away from your body 25 times faster than air does.

Which of the following statements are true?

Wave height is the distance from its highest point (crest) to its lowest point (trough). Wave length is the distance from crest to crest. Wave oscillation to calculated by multiplying the wave height times its length. Both the first and second answers are correct.

Which of the following statements is not true?

Wet suits are unnecessary in water warmer than 25 °C/77 °F.

When clearing a mask of water, you should form a seal by:

When clearing a mask of water, you should form a seal by:

The preferred way to remove moisture from a dust cap prior to putting it back in place is to:

Wipe it with a clean, dry towel or cloth.

Your dive computer indicates you need to make a mandatory decompression stop. You buddy's dive computer does not. You should:

You and your buddy should both follow the most conservative of the two dive computers.

All of the following are true except:

You can help prevent mask squeeze by exhaling periodically into your mask during ascent.

All of the following are true except:

You don't need to wear wet suit gloves to protect against cold until the water temperature drops below 10°C/50°F.

The three As of buoyancy control include all of the following except:

appreciation

___________ causes extreme headache and nausea, may cause the lips and fingernail beds to turn bright red and, in high enough concentrations, can cause unconsciousness.

carbon monoxide

Any time you cannot inhale while scuba diving (such as when a regulator is out of your mouth), you must be:

exhaling

Contact lens wearers should not close their eyes when clearing a mask.

false

If caught in a rip current, swim perpendicular to shore, until you are completely out of the rip current, then swim in towards shore.

false

Surge is the backwash of water from waves breaking on shore.

false

Taking decongestants is a good way to reduce the risk of ear or sinus squeeze.

false

To help prevent mildew, store equipment in a sealed container before it dries.

false

We measure waves by their height and weight.

false

At a depth of 30 m/99 ft, gas molecules in a flexible container will be packed ______ times more closely together than they will be at the surface.

four

Breathing deeply is up to ________ more times efficient as breathing shallow.

four

A wave encountering shallow water begins to slow at it bottom, while the top of the wave continues at its previous speed. This causes the wave to break.

true

Depending on circumstances, there are times when divers may wish to be positively, negatively or neutrally buoyant.

true

In general, the best time to dive is during slack tide, the period between high and low tides.

true

Objects under water appear 60 percent larger than they do on land.

true

The sun warming water near the equator, coupled with the earth's rotation, is the primary cause of permanent ocean currents.

true

When attempting to recover your primary second stage underwater, it is acceptable to switch to your alternate air source while you search for your primary.

true

Dry suits become almost essential in water temperatures below:

10 °C/50 °F

A scuba cylinder that normally lasts one hour at the surface will last _______ minutes at 20 meters/66 feet.

20

Hoods become necessary any time water temperatures drop below:

20°C/68°F

A regulator system may include:

A first stage and primary second stage. An alternate air source second stage (or a connection to an alternate-air-source inflator on the BC). A submersible pressure gauge (SPG), which is usually part of an instrument console. All of the above.

Which of the following statements is/are true?

A rip current is a narrow flow of swiftly moving water that runs perpendicular to shore. Rip currents form when water flowing out to sea is funneled through a narrow restriction, such as two sandbars or a break in a coral reef. The force of a rip current generally diminishes in deeper water, not far beyond the surf zone. All of the above.

Which of the following best describes the formation of surf?

A wave encountering shallow water begins to slow at its bottom, while the top of the wave continues at its previous speed. This causes the wave to break.

Key steps in descending and ascending include:

Agreeing with your buddy before doing either. Staying within your dive computer's allowable ascent rate. Using your BC to help control your rate of descent or ascent. All of the above.

The ABC pre-dive check acronym refers to:

Air on; BC inflated; Computer checked and activated.

What piece of equipment should never be allowed to dangle freely?

Alternate-air-source second stage. BC power inflator. Submersible pressure gauge or instrument console. Both the first and third answers are correct.

What causes most aquatic animal bites?

An animal's defensive response to a perceived threat. Sharks. Mistaken identity. Both the first and third answers are correct.