Laurie's Excellent Scuba Certification Quiz #1

Scuba tanks are typically made from aluminum or steel. These materials are used because they are strong and durable enough to withstand the high pressure of the compressed air or gas inside the tank. Aluminum tanks are lighter and more buoyant, making them easier to handle underwater, while steel tanks are heavier and more durable, making them suitable for deep dives and rough conditions.

When a diver displaces water equal to their own weight, it means that the upward force exerted by the water is equal to the downward force exerted by the diver's weight. This results in a balanced condition where the diver neither sinks nor floats, known as neutral buoyancy. Therefore, the statement is true.

If a person experiences discomfort or pain while descending, ascending a few feet can help make equalization easier. Equalization refers to the process of balancing the pressure between the middle ear and the surrounding environment, which is important for divers or individuals in high-pressure environments. By ascending a few feet, the pressure on the ears decreases, allowing for easier equalization and potentially relieving discomfort or pain. Therefore, the statement is true.

The hand signal of "slitting your throat" typically signifies that the person is out of air. This gesture is commonly used in situations where verbal communication is difficult or impossible, such as underwater or in loud environments. By making this hand signal, the person is indicating that they are running out of breath and need to surface or get more air.

A "drift dive" refers to a diving technique where a diver intentionally allows a current to carry them along. This can be done by descending into the water at a specific location and then allowing the current to carry the diver along a planned route. Drift diving can offer an exciting and effortless way to explore underwater environments, as the diver is carried along by the current and can observe marine life and underwater scenery without exerting much effort in swimming against the current.

The correct answer is "as a tool." A dive knife is primarily used as a tool for various purposes while diving, such as cutting through tangled ropes, lines, or fishing nets, prying open shells, or signaling underwater. While it can be used for self-defense in rare situations, its main function is to assist divers in practical tasks rather than as a weapon or for showing off.

Descending faster can actually increase the risk of ear squeeze, as the pressure changes in the ear can occur more rapidly. Holding your breath can also worsen the situation, as it can cause the pressure in the middle ear to build up. Breathing slowly and using the Valsalva maneuver (pinching the nose, tilting the head back, and breathing slowly) is a recommended technique to prevent ear squeeze. This maneuver helps to equalize the pressure in the middle ear by opening the Eustachian tube and allowing air to flow. Clearing every 2 feet while descending helps to maintain equalization throughout the descent.

RNT stands for Residual Nitrogen Time. This refers to the amount of time a diver must wait before ascending to the surface to allow their body to eliminate excess nitrogen absorbed during the dive. This is an important factor in dive planning to prevent decompression sickness.

The density of saltwater in the sea is higher than that of freshwater in a lake. This higher density of saltwater creates more buoyant force, allowing the diver to float more easily in the sea compared to a lake. Therefore, the statement is true.

The correct answer is 21% because oxygen makes up approximately 21% of the Earth's atmosphere. This is an important fact as oxygen is essential for the survival of many living organisms, including humans.

Nitrogen narcosis is a condition that occurs when a person dives to great depths underwater and experiences an altered state of consciousness due to the increased pressure of nitrogen in their body. The symptoms of nitrogen narcosis, such as impaired judgment, euphoria, and loss of coordination, are similar to those of alcohol intoxication. Both conditions can cause confusion, impaired motor skills, and a feeling of being "out of it." This similarity in symptoms is due to the fact that both alcohol and nitrogen affect the central nervous system, leading to similar impairments in cognitive and physical functioning.

When practicing neutral buoyancy, inhalations will cause you to rise and exhaling will cause you to fall. This is because when you inhale, you fill your lungs with air, which increases your overall volume and decreases your density. As a result, you become less dense than the surrounding water and experience a buoyant force that pushes you upwards. On the other hand, when you exhale, you release air from your lungs, reducing your volume and increasing your density. This causes you to become denser than the surrounding water and you will sink or fall.

BCD stands for Buoyancy Compensation Device. A Buoyancy Compensation Device is a piece of scuba diving equipment that allows divers to control their buoyancy underwater. It consists of an inflatable bladder that can be filled with air or released to adjust the diver's buoyancy. By adding air to the BCD, the diver becomes more buoyant and can ascend, while releasing air from the BCD makes the diver less buoyant and allows them to descend. This device is essential for maintaining neutral buoyancy and controlling depth during a dive.

During a descent to 50 feet, equalizing your body air spaces every few feet, before you feel any discomfort, is important. This is because as you descend, the pressure increases, which can cause discomfort and pain in your ears and sinuses. By equalizing your body air spaces regularly, you can prevent this discomfort and potential damage to your ears. Waiting until you feel discomfort or pain may indicate that the pressure has already built up too much, making it more difficult to equalize and potentially causing injury. Therefore, it is best to equalize every few feet to prevent any discomfort from occurring.

The most important feature of a weight system is that it has a quick release mechanism. This allows the diver to easily and quickly remove the weights in case of an emergency or if they need to adjust their buoyancy. It ensures the safety and comfort of the diver by providing a convenient and efficient way to release the weights when needed.

A thermocline refers to an abrupt change in water temperature. This phenomenon occurs when there is a rapid change in temperature with depth in a body of water. The thermocline acts as a barrier, separating warmer surface water from colder deep water. This temperature gradient can have significant effects on the distribution of marine life and can impact various oceanic processes such as nutrient cycling and oceanic currents.

Diving with a dive partner is essential for safety reasons. Having a dive partner ensures that there is someone to assist in case of emergencies, to share equipment, and to provide support and communication underwater. It is considered a fundamental rule in diving to always have a buddy system in place.

Surface waves are primarily caused by wind. When wind blows across the surface of a body of water, it creates friction and transfers energy to the water, causing it to move in a circular motion. These circular motions form waves that propagate across the surface. While underwater earthquakes, boats and ships, and underwater volcanoes can also cause surface waves, they are relatively less common compared to the influence of wind. Therefore, wind is the most likely cause of the large majority of surface waves.

The "divers down" flag is used to notify any boats in the area that there are divers in the water. This flag is displayed on a vessel or a buoy to indicate that there are divers below and that boats should proceed with caution. It is an important safety measure to prevent accidents and ensure the safety of the divers.

Descending too quickly is not likely to cause decompression sickness because decompression sickness, also known as "the bends," occurs when dissolved gases (usually nitrogen) come out of solution and form bubbles in the body during or after a decrease in pressure. Descending too quickly does not allow enough time for the gases to come out of solution and form bubbles, reducing the risk of decompression sickness.

Nitrogen narcosis is caused by increased levels of dissolved nitrogen in the blood. When a diver descends to great depths, the pressure causes nitrogen to dissolve into the bloodstream. This excess nitrogen can have a narcotic effect on the brain, leading to symptoms such as confusion, impaired judgment, and loss of coordination. It is not caused by a psychological defense mechanism, breathing compressed air for too long, or lack of oxygen to the brain.

Tides are caused by the gravitational attraction of the moon and the sun on the waters on earth. The moon's gravity pulls the water towards it, causing a bulge on the side of the earth facing the moon and a corresponding bulge on the opposite side. This creates high tides. The sun's gravity also contributes to the tidal forces, although to a lesser extent. As the earth rotates, different parts of the planet experience these bulges, resulting in the rise and fall of the tides. Deep ocean currents and waves do not directly cause tides.

Leaving a full scuba tank in the trunk of a car parked in the sun on a hot day can cause the tank to burst. This is because the heat can cause the air inside the tank to expand, creating excessive pressure. If the pressure becomes too high, it can exceed the tank's capacity and cause it to burst, potentially leading to a dangerous situation.

The term "the bends" is a common name for decompression sickness. Decompression sickness occurs when a diver ascends too quickly from a deep dive, causing nitrogen bubbles to form in the bloodstream. This can lead to various symptoms, including joint and muscle pain, dizziness, and difficulty breathing. The nickname "the bends" comes from the fact that the symptoms often include severe joint pain, which can cause the affected person to bend over in pain.

A mask squeeze is caused when the outside pressure is higher than the pressure in the air space in the mask. This can happen when a diver descends to greater depths where the water pressure increases. As the pressure inside the mask remains the same, the higher external pressure causes the mask to squeeze against the diver's face, potentially causing discomfort or injury. Therefore, the correct answer is False.

When light passes from one medium to another, such as from air to water, it changes speed and direction, causing refraction. This refraction causes objects underwater to appear larger because the light rays bend towards the normal, making the object seem magnified. Additionally, the refraction also makes the objects appear closer because the light rays bend away from the normal as they enter our eyes, giving the illusion that the object is nearer than it actually is.

Mask squeeze refers to the condition when the outside water pressure presses the mask tightly against your face. This can cause discomfort and potential injury to the diver's face and eyes. The pressure exerted by the water can be quite strong, especially at deeper depths, and can result in pain, bruising, and even broken blood vessels. It is important to properly equalize the pressure inside the mask by exhaling through the nose, ensuring a comfortable and safe diving experience.

It is recommended to always leave some pressurized air in the scuba tank. This is because an empty tank can lead to moisture buildup which can cause corrosion and damage to the tank. Additionally, leaving some pressurized air in the tank helps to prevent contaminants from entering and causing damage.

At sea level, the atmospheric pressure is 1 ATM. As you go deeper into water, the pressure increases by 1 ATM for every 33 feet. Therefore, at a depth of 33 feet, the pressure would be 2 ATM.

The average full pressure of a recreational scuba tank is typically around 3000 psi. This pressure is sufficient for most recreational diving activities and allows divers to stay underwater for a reasonable amount of time. Higher pressures, such as 6000 psi or 7500 psi, are more commonly found in technical diving setups or for specific diving purposes, while 1000 psi would be considered dangerously low and would require immediate attention.

Switching to your dive partner's alternate air source is the best course of action when you are out of air and your diving partner is close-by. This allows you to continue breathing while you ascend to the surface together, ensuring both of your safety. Signaling to ascend, filling your tank, and coming down again may take too much time and could potentially lead to a dangerous situation. Jerking your partner's regulator may cause panic and is not a recommended or safe approach.

If you hold your breath while scuba diving, several things can happen. Firstly, you can injure your lungs because the pressure underwater can cause damage if air is trapped inside. Secondly, you can sustain life-threatening injuries because the pressure can cause air to expand and damage your organs. Lastly, air can get released into your bloodstream, which can lead to serious complications like embolism. Therefore, all of the above options are possible consequences of holding your breath while scuba diving.

The common term for the time a diver spends at the surface to allow excess nitrogen to off gas from their blood and tissues is known as the "surface interval". This period is crucial for divers to ensure that they have enough time to eliminate the excess nitrogen absorbed during the dive, reducing the risk of decompression sickness.

When caught in a rip current, it is important to swim at a right angle to the current. This is because rip currents are powerful narrow channels of water that flow away from the shore. Swimming against the current can be exhausting and ineffective, as the current is usually too strong to overcome. Swimming with the current will only take the dive team further in the unwanted direction. By swimming at a right angle to the current, the team can escape the rip current and reach a safer area.

During ascent, releasing expanding air in your BC (buoyancy compensator) is important to prevent a rapid ascent. If the air is not released, it can cause the diver to ascend too quickly, which can lead to various complications such as decompression sickness or lung overexpansion injuries. Releasing the expanding air helps to maintain a controlled ascent rate and ensures the diver's safety.

If you are not able to equalize your body's air spaces while ascending or descending, a possible cause could be a cold or an allergy. Both a cold and an allergy can cause congestion and inflammation in the nasal passages and Eustachian tubes, making it difficult for air to flow in and out of the middle ear. This can lead to a feeling of pressure or discomfort in the ears and can make it challenging to equalize the air spaces while changing altitude.

The type and amount of suspended particles in the water can have a direct impact on the visibility. When there are more particles in the water, such as sediment or algae, it can reduce the clarity of the water, making it more difficult to see clearly underwater. This can affect activities like diving or snorkeling, as it may be harder to navigate or observe marine life. The dive computer, buoyancy, and water temperature are not directly affected by the suspended particles in the water.

If the regulator begins to "free flow" (release a lot of air) while underwater, it means that there is a malfunction in the regulator. Ascending while holding the regulator to your mouth without sealing your mouth around the mouthpiece allows you to continue breathing from the regulator, even though it is free flowing. This ensures that you have a continuous supply of air while safely ascending to the surface. Dropping your weight system and ascending to the surface may not be necessary if you can still breathe from the regulator. Sharing air with your diving partner is not necessary in this situation as long as you can breathe from your own regulator. Continuing the dive until you run out of air and have to ascend is not a safe option when there is a malfunction with the regulator.

The two basic parts of a regulator are the first stage and the second stage. The first stage is responsible for reducing the high pressure from the tank to an intermediate pressure, while the second stage delivers the air to the diver at a breathable pressure.

SCUBA stands for Self Contained Underwater Breathing Apparatus. This term refers to a diving equipment that allows divers to breathe underwater without being connected to the surface. The apparatus contains a tank of compressed air that the diver can breathe through a regulator. The correct answer option accurately describes the purpose and function of SCUBA equipment.

At sea level, you are exposed to 1 ATM (atmosphere) of pressure. This is because at sea level, the weight of the air above you exerts a pressure of approximately 1 atmosphere. As you go deeper underwater, the pressure increases, so at 33, 66, or 99 feet, the pressure would be greater than 1 ATM.

As one descends underwater, the pressure increases due to the weight of the water above. The pressure increases by one atmosphere (atm) for every 33 feet of descent. This is because the weight of the water column above adds an additional atmospheric pressure to the diver. Therefore, the correct answer is that the underwater pressure increases with one atmosphere (atm) every 33 feet while descending.

Nitrogen narcosis, also known as "raptures of the deep," is a condition that can occur when a diver descends to great depths. The increased pressure at these depths causes nitrogen to dissolve in the body's tissues, leading to symptoms similar to alcohol intoxication. While nitrogen narcosis can occur at various depths, it becomes most common and pronounced as the diver approaches 99 feet and deeper. At these depths, the effects of nitrogen narcosis can be severe and potentially dangerous, impairing judgment, coordination, and decision-making abilities. Therefore, depths approaching 99 feet and deeper are where nitrogen narcosis is most likely to occur.

Decompression illness, also known as "the bends," occurs when a person ascends too quickly from a deep dive or high-pressure environment. This condition can cause nitrogen bubbles to form in the bloodstream, leading to various symptoms such as joint pain, dizziness, and difficulty breathing. Administering 100% inhaled oxygen is a crucial first aid treatment for decompression illness. Oxygen helps to remove nitrogen from the body more efficiently, reducing the size of the bubbles and alleviating symptoms. Therefore, the statement is true.

Aquatic organisms can cause injuries during diving due to their defensive response. When they perceive a threat or feel endangered, they may react by attacking or defending themselves. This defensive behavior can result in injuries to the diver. Offensive, unintentional, and reflexive responses are not as likely to cause injuries in this context.

As you descend underwater, the pressure increases. This increased pressure causes the air trapped inside the wetsuit to compress, making the wetsuit tighter against your body. This compression also leads to a decrease in buoyancy, making it harder for you to float or stay at the surface of the water.

When planning a series of dives for one day, it is recommended to complete the deepest dive first. This is because the deeper dives can have a greater impact on the body and can cause nitrogen build-up in the tissues, which increases the risk of decompression sickness. By completing the deepest dive first, the body will have less nitrogen build-up, and subsequent shallower dives will have a lower risk. Resting for several hours in between dives and breathing pure oxygen are also important safety measures, but completing the deepest dive first is the most crucial step to minimize the risk of decompression sickness.

The air in a scuba tank is mainly composed of 21% oxygen and 79% nitrogen. This mixture is carefully balanced to provide enough oxygen for breathing while minimizing the risk of oxygen toxicity. The high nitrogen content is necessary to prevent nitrogen narcosis, a condition that can occur at depth due to the increased pressure. Therefore, the correct answer is 21% oxygen and 79% nitrogen.

The SPG, or Submersible Pressure Gauge, is a device that measures the pressure of the compressed air in a scuba tank. It allows divers to monitor the amount of air they have remaining during a dive and ensures they do not run out of air underwater. By keeping track of the pressure, divers can plan their dive and ascent accordingly to ensure a safe and controlled ascent.

According to Boyle's Law, when the volume of a gas decreases, the pressure increases. This is because as the volume decreases, the gas molecules are forced to occupy a smaller space, leading to more frequent collisions with the container walls, resulting in an increase in pressure. Therefore, pressure increases when the volume of a gas decreases.