Science of Scuba Diving
Spicer Bak
Stevens Institute of Technology
This material is based upon work supported by the National
Science Foundation under Grant No. NSF DGE-0742462
Overview
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Magnification
Light
Pressure
Boyles Law
Nitrogen Narcosis
Magnification
• Objects appear 33% larger
– 25% closer
• 3 m long object – 4 m away
– 33% larger – 33% of 3m is 1m = 4m
– Looking up at 45%
• 4m tall at distance of 4m
– 25% closer, appears 3m tall at distance 3m
• (3m tall at distance of 3m)
Science of Scuba Diving
Light Absorption
Boyle’s Law
Boyles Law
• P1*V1=P2*V2
– Pressure = P
– Volume = V
– As Pressure Increases
• Volume Decreases
• Applied to:
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BC
Lungs
Mask
Body
Pressure
Depth
Pressure
Volume
Air Density
Sea Level
1 ATM
12
1x
33'
2 ATM
6
2x
66'
3 ATM
4
3x
99'
4 ATM
3
4x
132'
5 ATM
2.4
5x
• With Depth, Pressure Increases
• Even in lungs and
• At Depth = 99 ft..
– 1 breath = 4xmolecules of air of normal breath
Boyles Law
• Decompression Sickness
– High Pressure increases nitrogen concentration in blood
• Turns Gas -> Liquid
– Dissolves in blood
– Come to surface too quickly
• Nitrogen goes from Liquid to Gas in blood stream (like
opening coke)
• Embolism
– Decompression Stops
• Stop at various depths during surface to reach equilibrium
• Emergency Surface
– Take Deep breath and blow out slowly as rise to the surface
• Gas expands, always have air
Nitrogen Narcosis
Nitrogen Narcosis
• With depth increases nitrogen in blood stream
– Under High Pressure Nitrogen Dissolves into blood
– Causes Nitrogen narcosis
• Effects
– Similar to Alcohol Intoxication
Nitrogen Narcosis
Signs and symptoms of narcosis (breathing air)
Pressure Depth Depth
Comments
(bar)
(m)
(ft.)
Unnoticeable small symptoms, or no
1–2
0–10
0-33
symptoms at all.
Mild impairment of performance of
unpracticed tasks.
2–4
10–30 33–100
Mildly impaired reasoning.
Mild euphoria possible.
Delayed response to visual and auditory
stimuli.
Reasoning and immediate memory
affected more than motor coordination.
Calculation errors and wrong choices.
4–6
30–50 100–165
Idea fixation.
Over-confidence and sense of well-being.
Laughter and loquacity (in chambers)
which may be overcome by self control.
Narcosis
6–8
50–70
165–230
8–10
70–90
230–300
10+
90+
300+
Sleepiness, impaired judgment,
confusion. Hallucinations.
Severe delay in response to signals,
instructions and other stimuli.
Occasional dizziness.
Uncontrolled laughter. Terror in
some.
Poor concentration and mental
confusion. Stupefaction with some
decrease in dexterity and judgment.
Loss of memory, increased
excitability.
Hallucinations. Increased intensity of
vision and hearing.
Sense of impending blackout,
euphoria, dizziness,
disorganization of the sense of time,
changes in facial appearance.
Unconsciousness. Death.
Nitrogen Narcosis - Solutions
• Normal – 78% nitrogen – 21% Oxygen
• Nitrox
– Mixes with higher oxygen content
– Very specific types of dives
• 68% N – 32% O2
• Others designed
• Oxygen Toxicity
– VENTID-C
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Vision (blurriness)
Ears-Ringing
Nausea
Twitching
Irritability
Dizziness
Convulsions
Nitrogen Narcosis
Does Free Diving have same Risks as Scuba Diving? Eg. Nitrogen
Narcosis, The bends?