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Unit 3: Diving Skills

Snorkeling Skills. Assembling scuba equipment. Donning scuba gear. Entering and exiting the water. Mask skills. Regulator skills. Buoyancy skills. Safety skills.

Buddy system. Communication. Handling your scuba equipment in the

water. Removing and replacing your scuba unit. Removing and replacing your weight belt. Navigation skills. Disassembling you scuba gear.

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Unit 4: Diving Science

Characteristics of Air and Water.

Buoyancy.

What is Pressure?

Your Body.

The Anatomy of Your Lungs.

Indirect Effects of Pressure.

Thermal Effects of Diving.

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cience • State some of the characteristics of air.

• Describe the concept of buoyancy and how it affects us under water.

• Describe the concept of pressure and how it affects volume and density in a closed container.

• Describe how pressure affects air spaces in our body and how prevent problems from pressure changes.

• State the different types of lung overpressure injuries and how to prevent them.

• Describe the indirect effects of pressure on our body.• Describe the thermal effects of air and water temperature

on our body.

Student Performance: By the end of the lesson students will be able to:

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Direct Effects of PressureYou will learn how pressure increases under water and how it affects your body.

When we descend in water, the force from the combined weight of air and water will increase.

Density and it’s Effects.

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The Air You BreatheMost of the time, we do not think about air, because breathing is an automatic activity.

Air is a mixture of gases.

Air can be easily compressed.

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In the WaterWater affects our vision, hearing, ability to retain heat and how we move through it.

The density of water at any depth is the same as the density at the surface.

Vision:

Colors:

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Hearing, Heat Loss, DragNoises sound different under water than they do in air.

Because of the greater density of water compared to air, sound waves travel about 4 times faster in the water than they do in air.

Heat Loss:

Drag:

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Review on Effects of DensityWhat have you learned so far?

List the two main components of air. Describe the difference in the density of air in

the mountains and at sea level. Describe the difference in the density of water

at 99 feet and 10 feet. Describe one way of reducing drag under

water. Describe how objects appear under water

compared to air. State how many times faster sound travels

under water.

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BuoyancyBy understanding buoyancy, you can control it to your advantage for diving.

Archimedes Principle:

States of buoyancy:

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Factors Affecting BuoyancyYour weight and your volume affect your buoyancy.

Your Weight includes the weight of your body and gear you wear.

Your volume depends on your body size, thickness of your suit, and your gear.

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Factors Affecting BuoyancyThe density of the water in which you dive also affects your buoyancy.

If you are weighted to be neutral in salt water and you dive in fresh water with the same amount of weight, you will sink.

Neutral buoyancy beneath the surface is:

Diving without buoyancy control is:

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Review on Buoyancy AffectsWhat have you learned so far?

Name three factors that affect your buoyancy.

List three ways you can change your buoyancy.

Describe what an ocean diver must do to their weight in order to dive in fresh water.

Describe what happens to a wetsuited diver’s buoyancy during descent.

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What is Pressure?When you descend in water, the force from the weight of the air and the water above you affects you.

This force is called pressure.

If you weighed a column of air.

This constant pressure is called 1 atmosphere of pressure.

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What is Pressure?When you descend in water, the force from the weight if the air and the water above you affects you.

Fresh Water:

Salt Water:

Units of Pressure:

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What is Pressure?When you descend in water, the force from the weight of the air and the water above you affects you.

Gauge pressure:

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Review on What is Pressure?What have you learned so far?

State the depths that are equal to one atmosphere in salt and fresh water.

State how many times greater the pressure is at 132 feet of sea water, than at the surface.

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How Pressure Affects VolumeTo understand the direct effects of pressure, consider the effects of pressure on an open and closed system.

Open system:

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How Pressure Affects VolumeThe effects of pressure on a closed system can be much more dramatic.

Closed System:

You must NEVER hold your breath when breathing compressed air under water.

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How Pressure Affects DensityYou use your air faster when you dive deeper.

Increasing pressure:

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Review on Volume and DensityWhat have you learned so far?

Describe what happens to pressure, volume, and density at 2ata, 3ata, and 4ata.

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Pressure and Air ConsumptionThe rate at which you consume the air in your cylinder is directly proportional to the depth you dive.

Air consumption factors:

Physical activity has the greatest effect.

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Monitoring Air ConsumptionAs you gain experience you can keep a record in a logbook of how long your air lasted at different depths and conditions.

Monitor your SPG, dive timer, and computer to determine when to begin your ascent.

Even if you calculate your air consumption mathematically, which is possible, many factors can change your predicted air consumption.

In certain specialty areas of diving, it is essential that you predict your air consumption to avoid running out of air.

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Review on Air ConsumptionWhat have you learned so far?

List two factors that affect your air consumption under water.

Name the device you check to monitor your air supply under water.

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Your BodyWhen you dive, the pressure of the water effects your air spaces as well as your breathing.

How pressure affects your air spaces.

Squeezes:

Blocks:

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The Middle EarYou must be able to equalize the pressure inside your ears to comfortably and safely dive.

Anatomy of the ear:

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Middle Ear SqueezesOccurs when the air or water pressure in your outer ear is greater than the air pressure in your middle ear.

Equalizing your middle ear:

Before you feel the slightest pressure in your ears, you need to equalize.

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Middle Ear SqueezesNever force equalizing your ears. You could cause serious damage to your ears.

The key to successful ear equalization:

If problems occur:

If you have a head cold, you must not attempt to equalize by any method.

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Middle Ear BlocksIf you begin to ascend and your ear hurts and feels “full”, stop your ascent and descend until the feeling goes away.

If the block does not equalize:

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SinusesYour sinuses are air cavities lined with mucous membranes and surrounded by the bones of your head.

Sinus squeeze and blockage:

Never dive when you have a cold or sinus congestion.

Decongestant drugs:

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Other Air SpacesAny air space trapped in or around your body will be affected.

Stomach and intestines:

Teeth:

Mask space:

Dry suit:

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Review on Your BodyWhat have you learned so far?

Name the air spaces in your body that are affected by pressure.

Describe why you should not dive with a cold. Describe what you should do when pressure is

felt on your face. Name the condition when pressure outside an air

space is greater than the pressure in an air space.

Name the most likely cause of sinus squeeze. Name the type of squeeze that is the easiest to

prevent. Name the condition when the pressure inside an

air space is greater than the outside pressure.

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The Anatomy of Your LungsYour lungs consist of millions of tiny air sacs, called alveoli.

Lung over-expansion injuries:

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Lung over-expansion injuries There are three general types of injuries.

Air embolism:

Pneumothorax:

Tissue Emphysema:

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Hyperbaric TreatmentIf you suffer an air embolism, you will need to treated in a recompression or hyperbaric chamber.

You should never go back under water to try to relieve symptoms.

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Breathing and CirculationTransporting oxygen through your body is a vital function of the circulatory system.

Carbon dioxide controls your breathing.

How to breathe under water.

Shallow breathing:

Hyperventilation:

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Breathing and CirculationTransporting oxygen through your body is a vital function of the circulatory system.

Skip breathing:

Air Starvation:

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Review on Lungs and BreathingWhat have you learned so far?

Describe the cause of lung over-expansion injuries.

Describe what your lung volume should be during ascent.

Name the component that stimulates breathing.

Describe the proper way of breathing on scuba.

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Indirect Effects of PressureThese indirect effects of pressure impact divers by means of the gases in the air we breathe while diving.

Ingassing and offgassing:

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Decompression SicknessCan occur if you absorb a great deal of nitrogen and then ascend to quickly.

It takes time for nitrogen to enter and to leave the body.

When bubbles form in your blood:

Prevention:

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Decompression SicknessIf you do suffer DCS you will need to be treated in a recompression chamber.

The chamber is pressurized to cause the nitrogen bubbles to go back into solution. Then slowly released.

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Nitrogen NarcosisWhen nitrogen is under pressure it can produce an effect on your body also called “rapture of the deep”.

At depths approaching 80 feet.

Oxygen toxicity:

Carbon Monoxide Toxicity:

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Review on Indirect EffectsWhat have you learned so far?

Describe how to avoid oxygen toxicity.

Describe how to avoid DCS.

Describe how to avoid nitrogen narcosis.

Describe what must be done if your buddy has symptoms of nitrogen narcosis.

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Thermal Effects of DivingYou loss heat under water in several ways.

Water conducts heat away from you body rapidly.

Breathing cold compressed air from a cylinder.

Humidity and temperature:

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Cylinders and TemperatureCylinders should be kept from extreme heat after they are filled.

The pressure will increase or decrease:

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Review on Thermal EffectsWhat have you learned so far?

Name two primary ways of losing heat while on scuba.

Describe how water vapor condenses to a liquid.

State what must be lowered in order to prevent a mask from fogging.

Name what drinking plenty of fluids helps to prevent.

Describe what happens to the pressure in a scuba cylinder if the temperature is increased.

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Diving Science: End of

Unit 4 Characteristics of Air and Water.

Buoyancy.

What is Pressure?

Your Body.

The Anatomy of Your Lungs.

Indirect Effects of Pressure.

Thermal Effects of Diving.

Div

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cience • State some of the characteristics of air.

• Describe the concept of buoyancy and how it affects us under water.

• Describe the concept of pressure and how it affects volume and density in a closed container.

• Describe how pressure affects air spaces in our body and how prevent problems from these pressure changes.

• State the different types of lung overpressure injuries and how to prevent them.

• Describe the indirect effects of pressure on our body.• Describe the thermal effects of air and water temperature

on our body.

Student Performance: By the end of the lesson students will be able to: