Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

PADI Divemaster 2024 > DM Chapter 9 Dive Theory Review > Flashcards

DM Chapter 9 Dive Theory Review Flashcards

1
Q

Why is a solid understanding of dive theory important?

A
  1. Answer questions.
  2. Solve problems that aren’t easily predicted or defined.
  3. Understand relationships, causes and effects.
  4. Function as a dive leader.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Water dissipates body heat faster than air does, because it absorbs heat approximately (blank) times faster than air does.

A

20

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Light (blank) when it passes through a substance of one density into a substance of a different density.

A

changes speed and directions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Due to refraction, underwater objects appear to be magnified by a factor of

A

4/3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Sounds travel faster in water than in air, because water is denser (more elasticity) than does air. T/F

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Sounds travels approximately (blank) times faster in water than in air.

A

4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Beacuse sound travels faster underwater, it is (blank) to determine the direction a sound is coming from while diving.

A

more difficult

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Depth = Pressure
00 ft =
33 ft =
66 ft =
99 ft =
132 ft =

A

Depth = Pressure
00 ft = 1 ata
33 ft = 2 ata
66 ft = 3 ata
99 ft = 4 ata
132 ft = 5 ata

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Absolute pressure

A

The total pressure, which is what you typically need to understand the effects of pressureon gases and your body.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Gauge pressure

A

Uses 1 ata as the zero point.

Pressure reading used by most gauges.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Ambient pressure

A

Surrounding pressure.

The pressure that exists around something at a defined moment.

Pressure on a diver at a given depth.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the absolute pressure at 79 feet in the ocean?

A

(79 / 33) + 1 = 3.4 ata

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Depth =
Pressure =
Air volume =
Air Density =

A

00 ft = 1 ata = 1 = (x1)
33 ft = 2 ata = 1/2 = (x2)
66 ft = 3 ata = 1/3 = (x3)
99 ft = 4 ata = 1/4 = (x4)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

If a diver is in fresh water at 34 feet, what is the ambient pressure?

A

2 ata

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

A diver in seawater at 66 feet brings a balloon of air to the surface. Assuming the balloon will not burst, its volume will be (blank) what it was at depth.

A

Three times

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

The density of a gas will be (blank) at 99 feet what it is at 33 feet.

A

Two times

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What will increase an object’s buoyance?

A
  1. Increase displacement
  2. Reduce weight
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Partial pressure

A
  1. The proportion of the total pressure exerted by a gas mixture that an individual gas exerts.
  2. Determined by multiplying the percent of the gas times the absolute pressure.
  3. Related to the solution of gases in liquid.
19
Q

What is the primary control of breathing called?

A

Reflex respiratory center

20
Q

What is ‘dead air’?

A

Gas that remains in your sinuses, trachea and bronchi.

21
Q

What is the most efficient way to breathe?

A

Breathe from diaphragm.

Abdomen should expand outward.

Diaphragm breathing draws air into the lower part of the lungs where about 75% of gas exchange takes place.

22
Q

What are the two types of O2 toxicity?

A
  1. Central nervous system.
  2. Pulmonary toxicity
23
Q

CNS Toxicity

A
  1. Immediate, life threatening threat.
  2. Risk becomes unacceptable when the PO2 exceeds approximately 1.4 ata AND a diver is active.
  3. Most severe sign is convulsion.
24
Q

VENTID

A

V = visual disturbance
E = ears ringing
N = nausea
T = twitching muscles
I = irritability
D = dizziness and vertigo

25
Q

Pulmonary O2 toxicity

A
  1. Results from continuous or repeated exposure to PO2 above 0.5 ata.
  2. Reaction occurs in the lungs.
  3. S/S burning in chest and an irritating cough.
26
Q

To avoid CNS oxygen toxicity, do not exceed a PO2 of

A

1.4 ata

27
Q

Gas narcosis

A

Narcotic effect that gases can cause when breathed under elevated partial pressures.

Type of anesthesia.

28
Q

Type I DCS

A
  1. Not immediately life threatening.
  2. Pain only - limb and joint pain.
29
Q

Skin bends

A

Cutaneous DCS that forms a rash.

Is considered Type I if it occurs by itself.

30
Q

Type II DCS

A
  1. Life threatening or debilitating.
  2. Neurological DCS.
  3. Stroke like symptoms/signs.
  4. Pulmonary DCS
31
Q

DCI = Decompression Illness

A

Overall term that includes both DCS and lung overexpansion injuries.

32
Q

Body response to excess heat.

A
  1. Skin capillaries dilate
  2. Perspiration
  3. Increase pulse
33
Q

Signs/Symptoms of Heat Exhaustion

A
  1. Weak and rapid pulse
  2. Profuse sweating
  3. Cool/clammy skin
  4. Nausea
  5. Weakness
34
Q

Signs/Symptoms of Heat Stroke

A
  1. Cessation of perspiration
  2. Skin hot and flushed
  3. Strong and rapid pulse
35
Q

A long, forceful equalization can cause window rupture. T/F

A

True

36
Q

Burst disk

A
  1. Part of the valve
  2. Ruptures if cylinder exceeds 140% of working pressure
  3. Thin cooper disk
37
Q

When gas flows to the second stage, pressure drops in the first stage intermediate pressure chamber. This causes the

A

first stage diaphragm/piston to open a valve releasing gas from the cylinder.

38
Q

An (blank) depth gauge operates on the principle of pressur causing a sealed coiled tube to coil tighter.

A

oil filled bourdon tube

39
Q

Electronic depth gauges and electronic SPGs both use a (blank)

A

transducer

40
Q

A mechanical SPG that reads high may be close to failure. T/F

A

True

41
Q

To account for the fact that the body doesn’t absorb and release inert gas on a single time scale, Haldanean models have several (blank)

A

tissue compartments

42
Q

The maximum value of a tissue compartment is represented by its (blank)

A

M - Value

43
Q

How fast a tissue compartment absorbs and releases gas is represented by its (blank)

A

halftime

44
Q
A

PADI Divemaster 2024 (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions