Basic Dive Physics Flashcards
General Gas Law
Boyle, Charles and Gay-Lussac demonstrated that T,V, and P affect a gas in such a way that a change in one factor must be balanced by corresponding change in one or both of the others.
Boyle’s Law
@ a constant T, the absolute P and V of gas are inversely proportional.
Charles/Gay-Lussac Law
@ a constant P, the V of a gas is directly proportional to the change in absolute T.
Dalton’s Law
The total P exerted by a mixture of gases is equal to the sum of the P’s of each of the different gases making up the mixture, c/ each gas acting as if it alone was present and occupied the total V.
Henry’s Law
The amount of any given gas that will dissolve in a liquid @ a given T is directly proportional to the pp of that gas.
Archimede’s Principle
Any object wholly or partly immersed in a fluid is buoyed up by a force equal to the weight of the fluid displaced by the object.
Kinetic Theory of gases
The kinetic energy of any gas @ a given T is the same as the kinetic energy of any other gas @ the same T.
SPAM
Squeezes
POIS
Air consumption
MMP - the amount of pressure your manifold compensates to allow comfortable breathing @ depth (overcoming the ambient pressure).
Partial Pressure:
The ____ is equal to the ____.
whole
sum
Partial Pressure relates to diving (2)
Gas toxicity (N2 narcosis and O2 to)
Re ‘C’ ops, determines TT’s
Natural factors that affect Buoyancy (4)
Air in lungs
Bone structure
Obesity
Leaness
Factors a diver can change to affect buoyancy (5)
add/remove weight put air in BC/LP put air in dry suit put air in lungs thickness of wetsuit
Pressure results in 2 factors
- hydrostatic pressure (wt of H2O)
- atmospheric pressure (wt of Atmosphere)
*the human body must maintain pressure balance because it can only fx correctly c/ little pressure difference between the body and the outside world.
Measurements of Pressure (4)
- Atm pressure = 14.7 psi
- gauge pressure = the difference between the Atm and the pressure being measured.
- ambient pressure = Atm + hydrostatic pressure.
- absolute pressure = total pressure exerted (gauge + Atm).
Numbers and Formulas: - ? wt of Atm = ?Atm = ? few = ? Ata Formulas: - psig - D to Ata - psig to Ata - Ata to pp of gas
- 14.7 psi = 1 Atm = 0 fsw = 1 Ata
- D x .445
- (D + 33) / 33
- (D + 14.7) / 14.7
- Ata x gas %
Wt of H20:
- Seawater
- Fresh water
- 64lbs
- 62.4 lbs
O2 properties (4)
21% of air
metabolized in the body
the only gas the body uses
can be toxic @ Ata 1.3-1.6 or greater.
N2 Properties (4)
79% of air
used to dilute O2
inert gas
cause N2 Narcosis
Inert Gas
Gas not metabolized by the body but dissolves in the tissue.
CO2
byproduct of respiration or metabolized O2.
CO
byproduct of incomplete combustion.
Humidity/Condensation:
- causes…
- how it affects dive equipment?
- discomfort to the diver (moisten tissues)
- can freeze and/or block passages, fog or corrode equipment.
Most dangerous change in pressure occurs between ___ Ata’s and ___ Ata’s.
1 and 2
CAR acronym
Charging bottles
Air and stowage
Re ‘C’ ops
Henry’s Law:
Factors that affect gas absorption (3)
depth, time, and condition of the body.
Henry’s Law:
Conditions of the body (3)
- gas T, decrease T then increases solubility.
- body T, decrease T then body vasoconstricts inhibiting off gasing.
- adipose tissue, holds 5x’s more inert gas (than water tissues) therefore takes longer to off gas.
Gas diffusion
The intermingling of/or mixing of gas molecules.
Energy in diving (3)
Light
Mechanical
Heat
Light:
- objects appear?
- light travels ___ in H2O than in air?
- color dissipates in what order?
- is affected by?
- closer
- faster
- ROYGBIV
- salinity, turbidity, size of particles, and pollution.
Mechanical (sound):
- ____ water is more dense.
- travels ___x’s faster in water because of increased ____.
- cold
- 4xs
- therefore more difficult to determine where sound is coming from.
Heat:
- Water is a better conductor of heat than air therefore @\_\_\_ deg F a diver loses heat faster than his body can replace it. - heat in water is lost \_\_\_ x's faster then in air. - a chilled diver is more susceptible to \_\_\_.
- 70 deg F
- 25
- DCS
Deviation from ‘D’ schedules may be done c/ (2)
recommendation of the DMO and concurrence of the CO.
Deviation from ‘D’ schedules is done only…
in emergencies.
When conducting SCUBA ops, the diver’s ___ is considered error free.
depth gauge.
Delay :01 then
add the delay to the 1st ‘D’ stop
* disregard delays between stops.
SCUBA ‘D’ dives can only be done when necessary c/ the authorization of the ___ or ___.
CO or OIC.
Unlimited BT c/ dives less than or equal to ___ fsw.
20 fsw
Ideally perform you deepest dives…
first.
Disregard delays…
< :01.
Delays >50’ and >:01 then
round the delay up & add to BT then recompute T/S and decompress accordingly.
- Never change the LB time when charting.
If the SI is ___, add multiple dive BT’s together and T/S for the deepest depth.
<:10
Charting is a ____ document.
legal.
RNT define.
Residual N2 Time - the left over N2 in the divers body after surfacing and the diver must account for it before repeat dives, flying, or being considered “clean”.
ESDT define
Equivalent single dive time - RNT+BT
If your SI is <:10 between dives then…
add the BT’s of the multiple dives and enter the T/S @ the deepest depth.
RNT exception rule
- the sum of your BT’s and chart with the deepest depth to determine ‘D’ obligation
- choose the shortest ‘D’ obligation between your charted dive vs the RNT exception rule.
- most likely with short SI dives.
Diving @ altitude requires ____ ‘D’ than dives@ sea level
longer
SLED
Sea level equivalent depth
- cannot be used c/ equipment that maintains a constant ppO2.
Elevation Correction Requirements:
- 0 to 300’
- 301 to 1000’
- 1001 to 10,000’
- 10,000’ +
- none
- if >145fsw
- all dives
- contact NAVSEA 00C
Flying after Diving:
Ascent in altitude after diving (ex: flying, hiking, driving, etc…) increases the risk of ___, due to the ___ in atm pressure.
DCS
reduction
Minimum SI required before flying depends on the planned altitude and the highest group designator obtained c/in the last ___ hrs.
24
commercial airlines are pressurized to ___ ‘
8000’
