PADI IDC PREP, PADI IDC - SS Final Exam Dive Skills - CL, Tina's PADI IDC Dive Theory Test (Dive Equipment), PADI IDC, Tina's PADI IDC Theory Review - (Recreational Dive Planner), Tina's PADI IDC Theory Review - (Recreational Dive Planner), Tina's PA...
A clenched fist brought toward the chest is a signal for: Choose your answer. A "I am out of air" B "I am out of air and want to buddy breathe" C "I am low on air" D "I am low on air and want to use your alternate air source"
"I am low on air"
Decompression sickness
"the bends" - a condition caused when gas bubbles form in the body after a dive
Balanced regulator
(1st stage) Most modern regs. Tank pressure doesn't resist or assist valve opening, so ease of breathing is not affected by depth
Unbalanced regulator
(1st stage) Out of fashion, b/c tank pressure affects ease of breathing, b/c tank pressure assists in opening the valve itself
RDP halftime
- 60 minute halftime for surface interval credit for no decompression repetitive diving - Includes multilayer profiles - Much broader demographic range than Navy, testing evaluated on Doppler detectable silent bubbles
Altitude dive ascent
- 9m/30ft per minute or slower - 3 minute safety stop at depth prescribed on Theoretical Depth at Altitude chart on all dives
Pressure group
- A letter used on the Recreational Dive Planner to designate the amount of theoretical residual nitrogen in the body
Residual nitrogen time
- An amount of nitrogen, expressed in minutes, for a specific depth added to the actual bottom time of a dive to account for residual nitrogen from a previous dive
Altitude
- Ascend into mountains = less air pressure - Cutoff: 300m/1000ft elevation, use RDP with special procedures - RDP cannot be used for dive at over 3000m/10,000ft elevation - No more than 2 dives/day - Do not make the 2nd dive at higher altitude
US Navy tables
- Based on the compartment with the longest/slowest halftime, 120 minutes - Newest USN tables even slower - Easy to use surface interval credit table based on the worst-case scenario: a repetitive dive preceded by a decompression dive
At altitude
- Body has higher nitrogen pressure than air - Remain at dive site altitude for 6+ hours - To dive sooner, count 2 pressure groups for each 300m/1000ft
Compartments
- Different parts of the body absorb nitrogen at different rates - Haldanean model is theoretical and shows that nitrogen absorption does not occur on a singular time scale (orginally had 5, then 6 compartments)
No stop dive
- Dive made within decompression limits - No required emergency decompression stops - AKA "no decompression dive"
Repetitive dive
- Dive that follows another while there is still a significant amount of residual nitrogen in the body - Using the RDP, usually made within 6 hours of the previous dive
Decompression diving
- Diving that requires planned stops during ascent to avoid DCS - In reactional diving, a decompression stop is considered emergency only, is not planned into the dive
Dive profile
- Drawing used to plan a dive with the RDP or eRDPml
Compartments and halftimes
- Each compartment has an assigned halftime - EX: 5 min. halftime compartment would equalize in 30 minutes, 60 min. halftime compartment would equalize in 360 minutes - Short halftime = fast tissue - Longer halftime = slow tissues
WX and YZ rules
- If you're planning 3 or more dives, beginning with the first dive of the day, if your ending pressure group is W or X, the minimum surface interval between all subsequent dives is 1 hour. - If your ending pressure group is Y or Z, the minimum surface interval between all subsequent dives is 3 hours.
Multilevel limit
- Maximum allowable no decompression time you have on each level of a multilevel dive
No decompression limit
- Maximum time that can be spent at a depth before decompression stops are requires - AKA "no-stop time"
Dive Computers
- More dive time with no unnecessary rounding - Personalized adjustment, remember how you dive -
Haldanean Decompression Model
- No direct relationship between the decompression model and the body - Supported by actual dive data - Model limits: models are imperfect can only be relied upon up to a point still risk DCS even within the limits
Ascent rate
- No faster than 18m/60ft per minute - Slower is better
Multilevel diving
- Profiles that credit you for slower nitrogen asorption when you ascend to a shallower depth
RDP
- Recreational Dive Planner - Created for no decompression diving - More compartments and longer halftimes than the 1950s US Navy tables
Emergency decompression stop
- Required when limit exceeded on RDP 1. No decompression limit is exceeded by 5 minutes or less - stop for 8 minutes at 5m/15ft, don't dive for 6 hours 2. No decompression limit is exceeded by more than 5 minutes - stop for at least 15 minutes at 5m/15ft - don't dive for 24 hours
Safety stops and ascents
- Safety stop at 5m/15ft after every dive - Don't add to bottom time - RDP safety stop if: dive to 30m/100ft or deeper dive comes within 3 pressure groups of a no decompression limit dive reaches no decompression limit - with RDP, max. ascent rate is 18m/60ft per minute
Different dive computer models
- Spencer Limits, EE washout (very similar to RDP) - Spencer Limits, 60 minute washout - Buhlmann Limits, EE washout (similar to RDP profiles)
Residual nitrogen
- The higher-than-normal amount of nitrogen remaining in the body after a dive
M-Values
- The maximum tissue pressure allowed in the compartment when the diver surface in order to prevent exceeding the maximum gradient - Exceeding the M-value in any compartment leads to an unacceptable risk of DCS - No decompression diving = only worry about surfacing M-value (M0-value) - Fast tissue = higher M-value - Slow tissue = low M-value
Total bottom time
- The sum of Residual Nitrogen Time and Actual Bottom Time of a repetitive dive on Table 1 of the RDP table, to determine the pressure group following a repetitive dive
Bottom time
- The time from the beginning of a descent until beginning a direct, continuous ascent to the surface or safety stop
Halftimes
- The time in minutes it takes for a particular compartment to go halfway from its beginning tissue pressure to equilibrium [saturation] at a new depth - 50% equilibrated after 1 halftime - 75% after 2 - 87.5% after 3 - 93.8% after 4 - 96.9% after 5 - 98.4% after 6 - after 6 it's basically 100% - exponential relationship
Adjusted no decompression limit
- The time limit for a repetitive dive that accounts for residual nitrogen - Actual bottom time should never exceed the the adjusted no decompression limit
Surface interval
- Time spent on the surface between two dives - Recorded in hours:minutes
3 current forms of the RDP
- Traditional RDP table - eRDPml - Enriched Air RDP
Actual bottom time (ABT)
- Used in repetitive diving - Added to Residual Nitrogen Time to account for residual nitrogen from previous dive = Total Bottom Time - Total amount of time actually spent underwater
Safety stop
- Usually at 5m/15ft for ~3 minutes - At the end of a dive for additional safety
Decompression model adjustments
- avoid and remove bubbles - accommodate extended no stop times while using enriched air nitrox
Submersible pressure gauge
- based on same principle as bourdon tube gauge - electronic SPG's use pressure transducer sim. to dive computers - may be integrated with dive computers - sometimes transducer is on reg 1st stage -> transmits to wrist computer
Digital pressure gauges
- electronic gauges that rread depth with transducer - transducer varies electricity transmitted based on pressuure - digital display - most accurate - used in dive computers
Diaphragm gauge
- flexible diaphragm -> moves levers + gears -> moves needle -> reading
"+" marking on tank
- indicates capacity for 10% overfill - only on steel tanks
altitude diving considerations
- narced shallower - theoretical depths + pressure
Visual inspection
- once a year - looking inside for corrosion (steel=rust, aluminum=aluminum oxide) - threading alsoo checked
Capillary depth gauge
- simple depth gauge design - with a tube of air that is compressed at depth - loses accuracy after 10m - according to PADI they're best for altitude diviing
Open bourdon tube gauge
- spiral tube - water enters and opens tube, producing depth reading - tube is open, so can clog
Oil-filled gauges
- use bourdon tube design - pressure is transmitted through oil -> affects coil -> moves needle -> depth reading - oil eliminates clog issue
Pressure changes per unit of fresh water =
.0432 psi/ft or 0.294 ATM/ft
At an altitude of 3000 metres the ambient air pressure is approximately 0.7 ata. What is the partial pressure of nitrogen at this altitude? Choose your answer. A .55 ata B .21 ata C .14 ata D The answer cannot be determined from the information given.
.55 ata
If an air-filled balloon is taken to a depth of 20 metres, what is the approximate partial pressure of oxygen in the balloon? Choose your answer. A .21 ata B .42 ata C .63 ata D The answer cannot be determined from the information given.
.63 ata
Pressure changes per unite of salt water =
0.445 psi/ft or 0.0303 ATM/ft
1
1
1 atm is how much bar
1 bar
diving and flying
1 dive - 12 hrs mulltiple - 18 hrs
Why is your judgement so important when applying standards?
1) Divers depend on you to make the course relevant for them individually. 2) Make judgement calls to minimise stress and anxiety. 3) Adapt the system to meet local diver needs. 4) Difference between adapting a skill versus adding a skill. 5) Elaborate points/skills rather than adding irrelevant info
Why should you always start with General standards and procedures guide in your PADI instructor manual?
1) It applies to all PADI courses. 2) Quick and easy to find info - e..g key standards table. 3) Don't try and memorise standards as they can change. 4) Do a quick review of standards before teaching. Read these two sections first - 1) Training standards and 2) Paperwork & administrative procedures.
What influences PADI standards?
1) Meet, exceed or comply with WRSTC, ISO and CEN standards. 2) Influenced by the diving scientific and medical community. 3) Influenced by conclusions from diver accident reports 4) Affected by changing equipment & technology 5) Evolve based on new instructional methodology & changing societal factors 6) Change when PADI members communicate a need for options, flexibility and revision.
What possible decisions and action may result from a quality of management inquiry?
1) Member realises their mistake - have counselling an compliance agreement. 2) Member does not understand the Padi standards - retrained 3) Member does not cooperate or chooses not to abide by standards - suspended, terminated or expelled. 4) When the severity of the situation warrants it, members are immediately place in Nonteaching status
What role does quality management play in the PADI system?
1) Provide for public safety and customer satisfaction. 2) Avoid or correct problems that create safety concerns or leave customers dissatisfied. 3) Maintain the integrity of PADI standards and programs. PADI's Quality Management = unique diver safety standards. - Requires you to report violations personally witnessed.
How do you keep up with standards changes?
1) Read quarterly training bulletins (announce new programs, materials and standard clarifications) 2) Read other PADI publications. 3) Attend PADI member forums and seminars 4) Enrol in an instructor-level continuing education course. 5) Receive a new PADI instructor manual each year
Why have standards?
1) Set foundations and provide boundaries 2) Provide worldwide consistency 3) Foster a systems approach (e.g. course sequence) 4) Basis for certification 5) Demonstrate strong and effective self regulation 6) Provide foundation for legal protection
How does the quality management process work?
1) Standardized for equal application e.g. methods consistent 2) Monitoring via Course Evaluation Questionnaires (CEQ's) 3) Inquries begin from - A) CEQ's, B) Allegations on quality management reports / complaints, C) Review of incident report forms
Why should you follow standards?
1) They exist for student safety 2) They provide structure, educational validity, credibility and a basis for legal protection. 3) Not following standards may result in incomplete training. 4) Don't add anything irrelevant or remove something important.
On courses Reduce ratios based on risk assessment
1) Water conditions - movement, temp, visibilty, depth, aquatic life, entry/exit logistics. 2) Weather conditions 3) Dive requirements 4) Number of certified assistants 5) Your personal abilities, limitations and familiarity with dive site 6) Participant age, ability, experience and comfort level Only use max ratios when you have adequate level of control
Tec Diving definition
1) diving more than 130 feet (40 metres); 2) required stage decompression; 3) diving in overhead environment beyond 130 feet; 4) accelerated decompression; 5) use of different gas mixtures on single dive
Two major causes of hypercapnia
1) high exertion 2) failing to breathe slowly and deeply
The seven Haldanean concepts
1. Upon descent to a certain depth, nitrogen dissolves from air into body tissues 2. Nitrogen continues to dissolve until the body saturates and can absorb no more at that depth 3. Upon ascent, the nitrogen dissolved in the tissues dissolves into breathing air and exhaled 4. Pressure gradient: the difference between the pressure of the dissolved nitrogen and the surrounding pressure 5. Upon ascent, some tissues can tolerate some gradient of high tissue pressure without DCS 6. If gradient exceeds tolerable limits, dissolved nitrogen comes out of solution faster than the body can eliminate it through respiration 7. DCS can be avoided by keeping the gradient within acceptable limits
Special rules
1. When diving cold/strenuous dives, plan the dive assuming the depth is 4m/10ft deeper than it is 2. Plan repetitive dives so that each successive dive is to the same or shallower depth 3. Limit maximum depth in consideration of training and experience 4. Use the W/X, Y/Z rule for multiple repetitive dives 5. Limit repetitive dives to 30 m/100ft or shallower 6. The 42m/140ft designation on the RDP is for emergency purposes only, do not go deeper than 40m/130ft (tested and proved) 7. If you go below 40m/130ft, ascend to 5m/15ft for 8 minutes (if the no decompression limit is not exceeded by more than 5 minutes), and don't dive for 6 hours
Standard tank markings (8)
1. max working pressure 2. max capacity 3. hydrostatic test date 4. hydrostatic testers mark 5. serial number 6. government agency 7. metal type 8. + (steel only)
Liter of fresh water weighs
1.0 kg
Seawater specific gravity
1.03
Liter of sea water weighs
1.03 kg
A scuba cylinder is accidentally filled with 1.2% carbon monoxide. Approximately what percentage of carbon monoxide will the cylinder contain if it is taken to a depth of 30 metres. Choose your answer. A 1.2% B 2.4% C 3.6% D 4.8%
1.2%
A scuba tank containing 1.5% carbon monoxide at the surfaceis taken down to 132 feet. If a diver were to breathe from the tank at this depth, it would have the same effect as breathing _____ percent of carbon monoxide at the surface?
1.5%
PADI Junior Certifications
10 years old or older can earn PADI junior OWD certification and those 12 years and older can be come junior AOW and junior RD. Same requirements as adult certs but require diving with an adult and some additional limits until the diver reaches the age of 15.
1 bar = ___m of fresh water
10.3m
A safety stop is recommended after all dives for 3 minutes at 15 feet for additional safety and recommended after all dives if air supply and other conditions allow it. It is required for dives to ____________ feet and within ____________ of the no decompression limit
100 feet 3 pressure groups
Deep Dive
100 feet (30 metres) or deeper
when using RPD limit repetitive dives to
100 feet or shallower
What is the no decompression limit for a dive to 43 mintues? (Use mRDP)
100 minutes
Most dive tables, including the Recreational Dive Planner, were not designed for use above an altitude of _____________. Choose your answer. A 300 metres/1000 feet B 400 metres/1312 feet C 4000 metres/13,000 feet D None of the above.
1000
You must follow special procedures to use the Recreational Dive Planner at altitudes higher than _______.
1000 feet
The signs and symptoms of nitrogen narcosis normally begin to occur at approximately what depth?
100ft.
1 bar = ___m of sea water
10m
1 atm of pressure is added for every...
10m of salt water 10.3m of fresh water
Pressure change examples
10m=1/2 atm 20m=1/3atm 30m=1/4atm etc.
When using a compass to navigate a triangle pattern with three sides the same length, set your bezel to turn _________ degrees at each corner. Choose your answer. A 90 B 60 C 20 D 120
120
RDP table
14 compartments 60 min halftime 6 hrs to be clean of nitrogen after a dive
A gas mixture is comprised of 21% oxygen, 78% nitrogen and 1% carbon dioxide. At a depth of 78 feet of seawater, what is the partial pressure of the oxygen? a. 49.41 psia b. 10.37 psia c. 7.28 psia d. The answer cannot be determined from the data provided.
14.7 x 3.5 = 51.45 x .21 = 10.8045 b. 10.37 This problem is identical to the two previous, except we must determine the absolute pressure using a different method. As the depth given — 78 feet of seawater — is not an increment of a whole atmosphere, we must derive the pressure using methods we explored in Objective 1.6. Therefore, to find the absolute pressure, we multiply 78 feet times the seawater constant of .445 psi/ft. Then, add the atmospheric pressure of 14.7 psi to determine the pressure as 49.41 psia: imperial calculation — (78 x .445) + 14.7 = 49.41; Next, we use the percentage of oxygen in the mixture, which is given as 21%, to find that the partial pressure is 10.37 psia: imperial calculation — .21 x 49.41 = 10.37
A _________ tissue compartment model was used to determine the no decompression limits for the Recreational Dive Planner and the surface interval credit table was calculated using a tissue half-time of ________.
14/60 minutes
The first stage reduces the high pressure to an Intermediate pressure and that pressure is usually between
140 - 190 psi above the ambient water pressure
If the blood did not contain the substance identified in the above question (hemoglobin), blood would have to circulate how many times faster to keep up with the body's demand for oxygen?
15-20 times.
RDP was developed in
1987
A diver completes a dive to 19.812m for 43 minutes. He wants to return to that depth for 32 minutes on the second dive. What is the minimum time the diver must wait on the surface before starting the second dive?
1:32
A diver completes a dive to 65 feet for 43 minutes. He wants to return to that depth for 32 minutes on the second dive. What is the minimum time the diver must wait on the surface before starting the second dive?
1:32
2
2
The absolute pressure in 15 metres/50 feet of sea water is: Choose your answer. A 1.5 ata B 2.5 ata C 3 ata D 2.45 ata
2.5 ata
If an object that weighs 187 pounds is neutrally buoyant in salt water, what is the volume of water the bject displaces?
2.9 cubic feet
Water is able to conduct heat about ______ times faster than air. Choose your answer. A 3200 B 775 C 100 D 20
20 times
Water conducts heat how much fast than air?
20 times.
Hemoglobin combines with carbon monoxide _______ times more regularly than oxygen.
200
Carbon monoxide binds with hemoglobin over____________times more readily than oxygen can, and it takes________for the circulatory system to eliminate it.
200 / 8-12 hours
carbon monoxide binds with hemoglobin over____________times more readily than oxygen can, and it takes________for the circulatory system to eliminate it.
200 / 8-12 hours
Approximately how much air must be pumped down from the surface to fill a 40 litre container if the container lies in 40 metres of salt water? Choose your answer. A 160 litres B 100 litres C 40 litres D 200 litres
200 litres
If it takes a diver 90 minutes to breathe all the air from a scuba tank at the surface, approximately how long will the air in that tank last at 30 metres? Choose your answer. A 22.5 minutes B 20 minutes C 30 minutes D 37.5 minutes
22.5 minutes
A diver exits the water after a dive to 21.336m for 31 minutes. The diver reenters the water 49 minutes later for another dive to 21.336m - what is the max allowable time he may spend at this depth?
24 minutes
A diver exits the water after a dive to 70 feet for 31 minutes. The diver reenters the water 49 minutes later for another dive to 70 feet - what is the max allowable time he may spend at this depth?
24 minutes
A diver plans to do three dives using minimum SI. The planned profiles are: 12m for 92 minutes, 33m for 13 minutes and 15.24m for 54 minutes. Arrange the dives in the appropriate order and calculate how many total minutes it will take to complete from descent of the first dive to surfacing on the last dive (can ignore ascent time, but not required safety stop.
240 minutes
A diver plans to do three dives using minimum SI. The planned profiles are: 40 feet for 92 minutes, 108 feet for 13 minutes and 50 feet for 54 minutes. Arrange the dives in the appropriate order and calculate how many total minutes it will take to complete from descent of the first dive to surfacing on the last dive (can ignore ascent time, but not required safety stop.
240 minutes
If a sealed, flexible, air filled container with a volume of one litre at 20 metres is released, what will its volume be when it reaches the surface (given that it doesn't explode)? Choose your answer. A 1 litre B 2 litres C 3 litres D 4 litres
3 litres
Smoking cigarettes prior to diving can raise the carbon monoxide__________times above-normal, which in turn___________.
3-12 / impairs oxygen transport in carbon dioxide elimination
smoking cigarettes prior to diving can raise the carbon monoxide__________times above-normal, which in turn___________.
3-12 / impairs oxygen transport in carbon dioxide elimination
If a diver breathes air that contains 0.9% carbon monoxide at 30 metres/99 feet of sea water, this would have the same physiological effect on the diver as breathing what percentage of carbon monoxide at the surface? Choose your answer. A .9% B 1.8% C 3.6% D 4.5%
3.6%
What is the gauge pressure at 38 metres of fresh water? Choose your answer. A 3.68 atm gauge B 3.8 atm gauge C 4.8 atm gauge D 4.68 atm gauge
3.68 atm gauge
the ascent rate at altitude is
30 feet per minute or slower make a safety stop on all dives
You must follow special procedures to use the Recreational Dive Planner at altitudes higher than _______.
304.8m
Pressure of salt water increases by 1 ATM every
33 feet
Pressure of fresh water increases by 1 ATM every
34 feet
Which of the following tank markings designates the type of metal used to construct the scuba tank? A 3AL B 7@89 C 675432 D 3000
3AL
Which of the following cylinder markings designates the type of metal used to construct the scuba cylinder? O 3AL O 7@18 O 675432 O 3000
3AL - In North America, the marking 3AL designates aluminum and in Canada, 3ALM is aluminum. Steel cylinders may have a designation of 3AA.
Which of the following cylinder markings designates the type of metal used to construct the scuba cylinder
3AL, As 1777
Sound travels how much faster in water than air?
4 times
When using enriched air with up to _________ oxygen generally, you may use standard scuba equipment (except cylinder), use of oxygen compatible lubricants is generally recommended, and follow all manufacturer recommendations regarding using their equipment with enriched air. A 40 percent B 36 percent C 38 percent D None of the above.
40 percent
Gas mixes with more than ______________ percent oxygen requires equipment that has been cleaned to oxygen service specifications
40%
Wavelength range perceptible by humans
400 nm to 760nm; differences within this range we perceive as color; we see color based on the wavelengths an object reflects; wavelengths relate to the amount of energy in light (red end of the spectrum as less energy that the blue end)
Water has ___ more heat capacity than air.
4x
To what pressure is a scuba cylinder filled during the hyrdrostatic test?
5/3 's of its working pressure
During a hydrostatic test a scuba cylinder is generally pressurized to ________ of it's working pressure. A 5/3's B 3/5's C 9/10's D 1/2
5/3's
A 175 kilogram/385 pound cement block that displaces 115 litres/4 cubic feet of water lies on the bottom in 14 metres/46 feet of salt water. What is the minimum amount of water that must be displaced from a lifting device to bring the block to the surface? Choose your answer. A 65 litres B 60 litres C 54.9 litres D 110 litres
54.9 litres
A diver is planning a multilevel dive with three levels - 100, 70, and 45 feet. If he plans to stay to the multilevel limit at each depth - approximately how long will he spend underwater? (ignore ascent times but not required stop time)
56 minutes
A diver is planning a multilevel dive with three levels - 30.48, 21.336, and 13.716 m. If he plans to stay to the multilevel limit at each depth - approximately how long will he spend underwater? (ignore ascent times but not required stop time)
56 minutes
US Navy Tables
6 compartments 120 min halftime 12 hrs to be clean
if your diving above 8000 feet wait
6 hours before diving
Non Yellow cylinder markings should have a
6" band around it top 1" and bottom 1" should be a yellow band the middle 4" should be a green band the wording should be either yellow or white saying enriched air or nitrox
A diver completes a 86 foot dive for 19 minutes. After a 58 minute SI, he wants to make another dive - what is the maximum allowable depth he may attain on this second dive to stay for 35 minutes?
60 feet
1 cubic foot of fresh water weighs
62.4 pounds
1 cubic foot of water weighs
64 pounds
A 200 kilogram anchor that displaces 127 litres/4.5 cubic feet of water lies on the bottom in 17 metres/56 feet of sea water. What is the minimum amount of water that must be displaced from a lifting device to bring the anchor to the surface? Choose your answer. A 67 litres B 73 litres C 127 litres D 69.1 litres
67 litres
A steel cylinder whose capacity is 71.2CF at 2475psi and an aluminum cylinder whose capacity is 100CF at 3000psi are both filled to 2000psi. Which cylinder contains more air?
71.2 / 2475 = .029 x 2000 = 58CF 100 / 3000 = .033 x 2000 = 66CF Aluminum = 66CF
The gauge pressure at 75 feet of depth in fresh water is: a. 32.4 psig b. 47.1 psig c. 61.8 psig d. The answer cannot be determined from the data provided.
75 x .432 = 32.4 The gauge pressure at 75 feet of depth in fresh water is: 32.4 psig. Remember, gauge pressure ignores the atmospheric pressure — like your depth gauge. Therefore, this time we are only concerned with finding out how much pressure is exerted by the water column. To do that we multiply the depth (remember it's fresh water) of 75 feet times .432 psi/ft to determine that 32.4 psig is being exerted by the water.
Which of the following cylinder markings designates the hydrostatic test date? O 3AL O 7@18 O 675432 O 3000
7@18 - The hydrostatic test date marking consists of numbers representing the month and year in which the cylinder was tested.
Which of the following cylinder markings designates the hydrostatic test date
7@89
Which of the following tank markings designates the hydrostatic test date? A 3AL B 7@89 C 675432 D 3000
7@89
Emergency deco stop rules
8 min if NDL is exceeded by <5 min 15 min if NDL is exceeded by >5 min 8 min if accidentally below 40m + don't dive for 6 hrs no diving 24 hours if missed req. deco stop + emergency o2
PADI Seal Team and Bubblemaker
8 years and older can scuba dive in a pool or shallow confined water area with pool-like conditions. Bubblemaker status allows kids to experience scuba diving but Seal Team offers a series of pool activities that build skills that transfer to PADI junior OWD.
For a breathing patient of a near-drowning you should: (check all that apply) Choose your answer. A be prepared to turn the patient and keep the airway clear B give emergency oxygen C keep the patient lying down D treat for shock, contact EMS
A be prepared to turn the patient and keep the airway clear B give emergency oxygen C keep the patient lying down D treat for shock, contact EMS
Henry's Law
A big cokehead - as pressure increases, more gas will dissolve in a liquid
If a diver complains of DCI symptoms immediately on reaching the surface, what is the most likely cause?
A lung overexpansion injury
Heat Capacity
A measure of the amount of heat that must be added or removed from a substance to make it change temperature a given amount.
If you are having difficulty with ear equalization, and you blow too hard against a pinched noseyou could cause what injury?
A round window rupture.
A recreational diver suspected of having decompression illness ______________. (check all that apply) Choose your answer. A should be given as close to 100 percent concentration of oxygen supplied by a nonresuscitator demand valve unit B kept lying down and told to relax C protected from heat and cold D can be recompressed by putting the patient back underwater
A should be given as close to 100 percent concentration of oxygen supplied by a nonresuscitator demand valve unit B kept lying down and told to relax C protected from heat and cold
Halocline
A transition between a freshwater and a saltwater layer
Under what circumstances should a scuba cylinder be visually inspected? (choose all that apply) A Air compressor defective or air smells unusual B The valve is removed C After hydrostatic re-test D Cylinder exterior is damaged E Burst disc fails F Its previous history is unknown
ALL
What situations dictate a need for a compass? (choose all that apply) A When diving in low visibility water B When diving in midwater C When diving at night D When you can't use natural references to navigate
ALL answers
To plan a dive with your computer: (choose all that apply) A scroll the NDLs to find the limit for your planned depth. B agree on a time limit with your buddy. C write down the NDL for your planned and next greater depth. D plan dives so the maximum depths are progressively shallower.
ALL of the above
If your computer fails: (choose all that apply) A during a dive, use your backup computer if you have one. B during a dive, share your buddy's computer. C between dives, use your backup computer if you've been diving with one. D you may be able to resume diving using tables.
ANSWER: A, C, & D
arterial gas embolism
Air enters the bloodstream and flows into arteries Serious and immediately life threatening. Bubbles can lodge anywhere, but the most common is to flow through the carotid arteries and cause cerebral air embolism, which can stop blood flow to parts of the brain depending on where in the arteries the embolus lodges) Signs and symptoms (similar to a stroke): Dizziness, Confusion, Shock, Paralysis (of face, arms or legs, usually one-sided), Personality change, Unconsciousness and death Also Difficulty speaking or understanding other people Strange sensations like pins and needles or numbness Visual disturbance
subcutaneous emphysema
Air from a rupture accumulates in soft tissues under the skin usually at the base of the neck. The victim feels fullness in neck and voice may change. Signs and symptoms The skin may crackle to the touch
pneumothorax
Air from a rupture goes into the pleural space between the lung and chest wall causing the lung (or part of it) to collapse. Also serious. Signs and symptoms Chest pain (particularly on breathing in), increasing breathlessness (these are the cardinal signs). Patient may cough up blood
Mediastinal emphysema
Air from the rupture accumulates in the centre of the chest, over the heart, causing pain in the middle of the chest, this is serious because air presses on the heart and vessels, interfering with circulation (affects ability of heart to pump effectively). Signs and symptoms Patient may feel faint or short of breath.
Residual volume
Air left in your lugs after you exhale completely
Ideal gas law
All gases behave according to the same ideal law (most gases have same properties with respect to pressure/volume relationships, pressure changes with temperature changes, and so on)
Factors that influence a diver's susceptibility to decompression sickness include: A consuming alcohol before or after a dive. B heavy exercise. C obesity. D All of the above are correct.
All of the above are correct.
Slow deep breathing is best because: A the proportion of dead air space to fresh air is reduced thus maximizing the usable air reaching the lungs. B air turbulence is decreased thus reducing breathing resistance. C the elimination of carbon dioxide is maximized. D All of the above are correct.
All of the above are correct.
Under what circumstances should a scuba cylinder be visually inspected? (Choose all that apply.) O After hydrostatic re-test O Cylinder exterior is damaged O Cylinder burst disc fails O Anytime the cylinder is completely emptied during use
All of these are reasons for a visual inspection.
What is residual nitrogen time
An amount of nitrogen expressed in minutes for a specific depth the higher than normal amount of nitrogen remaining in your body after a dive
Stable (chemistry)
An atom that has the max number of electrons in its outermost shell and will not react with other atoms. Examples of this are the inert gases such as helium and neon.
Reactive (chemistry)
An atom with an electron formation that allows it to form a chemical bond; reactivity depends on the number of electrons in its outermost shell.
Archimedes' Principle
An object wholly or partially immersed in a fluid is buoyed up by a force equal to the weight of the fluid displaced by the object.
Archimedes' Principle
Any object wholly or partially immersed in a fluid is buoyed up by a force equal to the weight of the fluid displaced by the object.
Explain how a lung over-expansion injury can occur even to a diver who is breathing normally?
Any obstruction that prevents the normal release of air from the lungs can cause over pressurization. These obstructions can occur for various reasons. Even though the diver me breathe normally, obstructions deep in the lung may not allow air to escape. Various diseases such as asthma and other pulmonary disorders can cause these obstructions. However, a more prevalent cause lung obstruction in divers are those resulting from smoking cigarettes, or diving after a severe chest cold.
explain how a lung over-expansion injury can occur even to a diver who is breathing normally?
Any obstruction that prevents the normal release of air from the lungs can cause over pressurization. These obstructions can occur for various reasons. Even though the diver me breathe normally, obstructions deep in the lung may not allow air to escape. Various diseases such as asthma and other pulmonary disorders can cause these obstructions. However, a more prevalent cause lung obstruction in divers are those resulting from smoking cigarettes, or diving after a severe chest cold.
Water and ice
As water cools, it becomes more dense just like any other liquid, but only until it reaches 4C/39F. Unlike most substances, solid water is less dense than liquid water, which is why ice floats.
If a computer fails during a dive you can
Ascend, make a safety stop and end the dive continue the dive with a backup computer
Isotopes
Atoms of an element that have a different number of neutrons (but same number of protons)
Covalent bonding
Atoms share electrons to complete their outer shell (e.g. water)
An 80 cubic foot scuba cylinder is filled to 3000 psig at an ambient temperature of 80° F. If the cylinder is then used in water temperature of 40° F, what would be the approximate cylinder pressure? a. Unchanged b. 2800 psig c. 3400 psig d. 2840 psig
B. 2800 There is a way to roughly estimate the effect of temperature on the pressure within a scuba cylinder. When using the Fahrenheit scale, the rule of thumb is that for every change in temperature of one degree, a corresponding change of 5 psig will occur. This question is expressed in Fahrenheit, and a 40° drop occurs, resulting in about a 200 psig reduction in pressure (40 x 5 = 200). Therefore, 3000 psig - 200 psig = 2800 psig.
Imagine you are very low on air and about to run out. What would you do? Please select the correct sequence of preferences from the choices listed. (You may need to scroll down to see the "Check Answer" button) Choose your answer. A 1. alternate air source ascent (using your buddy's alternate air source), 2. controlled emergency swimming ascent (CESA - swimming up to the surface saying ah-h-h-h), 3. buoyant emergency ascent (dropping your weight system, 4. normal ascent (going up normally). B 1. normal ascent (going up normally), 2. alternate air source ascent (using your buddy's alternate air source), 3. controlled emergency swimming ascent (CESA - swimming up to the surface saying ah-h-h-h), 4. buoyant emergency ascent (dropping your weight system). C 1. buoyant emergency ascent (dropping your weight system, 2. controlled emergency swimming ascent (CESA - swimming up to the surface saying ah-h-h-h), 3. normal ascent (going up normally), 4. alternate air source ascent (using your buddy's alternate air source). D 1. controlled emergency swimming ascent (CESA - swimming up to the surface saying ah-h-h-h), 2. buoyant emergency ascent (dropping your weight system), 3. alternate air source ascent (using your buddy's alternate air source), 4. normal ascent (going up normally).
B: 1. normal ascent (going up normally), 2. alternate air source ascent (using your buddy's alternate air source), 3. controlled emergency swimming ascent (CESA - swimming up to the surface saying ah-h-h-h), 4. buoyant emergency ascent (dropping your weight system).
6 components of the recreational scuba system
BCD Inflation System (LPI) Alternate Air Source (octo) BCD Regulator SPG Weights
What is a pressure related injury called? ( It can happen on both ascent and descent )
Barotrauma. If we were to analyse this word.. we have Bar ( pressure ) and Trauma ( Injury )So, put them together and we have Barotrauma = Pressure related injury.
Why does DCS in recreational divers involve nitrogen bubbles but not oxygen bubbles?
Because the oxygen we breathe is used up in the metabolic process.
why does DCS in recreational divers involve nitrogen bubbles but not oxygen bubbles?
Because the oxygen we breathe is used up in the metabolic process.
DCI
Blanket term for Decompression sickness(DCS) and lung overexpansion injuries.
How do you avoid dead air space problems?
Breathe slowly and deeply.
what decompression model is most commonly used in dive computers
Buhlmann limits - EE Washout Spencer Limits - 60 minute washout
1.4bar
CNS oxygen toxicity becomes an issue reaching what depth maximum?
Carotid-sinus reflex
Carotid arteries brings arterial blood to your brain; carotid-sinus receptors continuously monitor blood pressure within carotid arteries. If the receptors detect high blood pressure, they stimulate the cardioinhibitory center which slows your heart.
If a diver had a tight neck seal, what would be the likely cause of light headedness?
Carotid sinus reflex
Hemoglobin
Carries Oxygen
Arteries
Carry blood away from heart
Veins
Carry blood to the heart
shallow water blackout
Caused by excessive hyperventilation, depleting a divers carbon dioxide level. At depth, a divers body consumes oxygen faster than carbon dioxide accumulates to stimulate breathing. Depleted oxygen causes no problem at depth because high pp allows haemoglobin to bond with the remaining supply. The diver ascends, the pp drops and haemoglobin can no longer bond with oxygen;
round window rupture
Causes: Caused by delayed equalization accompanied by forceful Valsalva manoeuvre (exhaling against pinched nostrils). Signs and symptoms: Valsalva raises pressure in thorax, which causes increase in pressure in cochlea (connected by fluid as part of the nervous system).This plus transmitted pressure bursts round window outward.
Middle ear squeeze
Causes: Failure to equalize or inability to equalize due to congestion, diving with a cold) Signs and Symptoms: Sharp pain caused by the hydrostatic pressure forcing the eardrum inward towards the airspace with less pressure (i.e. inside your ear)
Subcutaneous Emphysema: causes and symptoms
Causes: Air accumulates at the base of the neck in soft tissue Symptoms: Fullness in neck, voice change, skin that crackles when touched
Mediastinal Emphysema: causes and symptoms
Causes: Air accumulates in center of chest over heart Symptoms: Feeling faint and shortness of breath
Pnuemothorax: causes and symptoms
Causes: Air goes between lung and chest wall causing lung to collapse Symptoms: Chest pains and coughing up blood
Air Embolism: causes and symptoms
Causes: Alveoli and capillaries rupture causing bubble to enter blood stream Symptoms: Dizziness, confusion, shock, paralysis, personality change, unconsciousness, and death.
Heat Stroke: causes and symptoms
Causes: Body has reached its limits Symptoms: Strong rapid pulse, no perspiration, and hot flushed skin
Heat Exhaustion: causes and symptoms
Causes: Body works at full capacity to cool itself Symptoms: Weak rapid pulse and breathing, profuse sweating, cool clammy skin, dehydration, and nausea.
Pulmonary Toxicity: causes and symptoms
Causes: Continued exposure to elevated oxygen levels Symptoms: Burning in the chest and irritated cough
Central Nervous System Toxicity: causes and symptoms
Causes: Exposure to PO2 greater than 1.4-1.6 atm. Symptoms: visual disturbances, ear ringing, nausea, muscle twitching, irritability, dizziness, and convulsions.
The various factors that increase the divers susceptibility to decompression sickness relate primarily to:
Changes to circulation.
the various factors that increase the divers susceptibility to decompression sickness relate primarily to:
Changes to circulation.
Emile Gagnan
Co-developed the open circuit compressed air regulator with Jacques Cousteau in 1943.
Surface equivalency
Comparing the effects of a single gas in a mix breathed at a particular depth with the effect of a greater percentage of the same gas at the surface.
Conduction vs convection
Conduction is through direct contact Convection is sweeping warm water away
What is the first aid procedure for a lung overexpansion injury?
Contact emergency medical servicesKeep the patient lying level, administer Oxygen ( 100 pct. if possible ) and monitor the patients breathing.
Color absorption
Continual process by which water absorbs wavelengths with less energy more easily; by 15 feet, red is gone. There's less of all colors at 6 feet than there is at 3 feet. Color absorption is a function of the total distance light travels through water.
Reflex respiratory centers
Control breathing by stimulating the urge to breathe when carbon dioxide is detected above distinct levels
Identify the type of valve pictured. (valve w/nothing in the stem). A K valve B J valve C DIN valve D Yoke valve
DIN valve
Identify the indicated part of a cylinder valve. (Downward tube) A Burst disc B High pressure port C Low pressure port D Debris tube
Debris tube
What is the blanket term that covers both lung overexpansion injuries and Decompression sickness?
Decompression Illness
Volume_________ as pressure _________, causing density to __________
Decreases, increases, increase
Subdivisions of Tec Diving
Deep diving; trimix diving; cave diving; technical wreck diving; technology-specific diving
Two factors that affect gas absorption are?
Density of the tissue and blood flow.
two factors that affect gas absorption are?
Density of the tissue and blood flow.
DOT/CTC stand for
Department of Transportation Canadian Transport Commission
To find pressure from depth
Depth/pressure standard= pressure at depth: ex: in salt water 30m/ (10m/1atm)= 3atm or 4ata.
Benoit Roaquayrol
Developed first open circuit demand scuba in 1865 with Auguste Denayrouze
Auguste Denayrouze
Developed first open circuit demand scuba in 1865 with Benoit Rouquayrol
Raymond E. Rogers
Developed the Recreational Dive Planner
Pressure gradient
Difference between the partial pressure of gases in contact with a liquid and the gas tension within the liquid
Light loss underwater comes from:
Diffusion, Reflection, and Absorption.
Amadeo Avogadro
Discovered that a given volume at the same temperature and pressure always has the same number of gas molecules, no matter what gas the volume holds.
Methods of determining time under water
Dive Watches Dive Computers
Technical deep diving
Dives deeper than 130 feet typically requiring decompression stops; training focuses on equipment, calculations, and using different gas blends. Qualifies divers to dive as deep as 165 feet.
Recreational diving
Diving no deeper than 130 feet (40 metres) with the no stop limits of recognized dive tables or dive computers. Must be within 40 metres/130 feet of the surface or within sight of light from the surface if diving in overhead environment.
What is the device used to detect the presence of silent bubbles?
Doppler ultrasound flow meter
The two most common blends of enriched air are
EANx32 & EANx36
Two most common enriched air blends
EANx32 - NOAA Nitrox I EANx36 - NOAA Nitrox II
_________ and ________ are the two most common blends of enriched air. A EANx30 and EANx40 B EANx32 and EANx36 C EANx30 and EANx36 D EANx32 and EANx40
EANx32 and EANx36
Fluorescents
EMIT color when stimulated by light of any shorter wavelength; these colors stand out at depth
Reverse squeeze
Ears equalize on decent but congestion at depth prevents air from escaping during ascent. Eardrum flexes outward Causes: Usually caused by diving with a cold using decongestants (decongestant wears off during dive causing blockage) Signs and symptoms:Reduced hearing,Vertigo,Balance problems,Ear ringing,A feeling that the ears are blocked
Follow all manufacturer recommendations with respect to using equipment with
Enriched Air
You need a dedicated cylinder for _________________
Enriched Air Diving
EANx
Enriched Air Nitrox - air that has had oxygen added to reduce the proportional amount of nitrogen and thereby increase the allowable no stop dive time.
Technical wreck diving
Entering the structure of a sunken ship and penetrating beyond 130 linear feet from the surface
Speed of sound
Entirely depends on the matter through which it travels; in air at sea level at 0C/32F sound travels at about 332m/1087ft/sec; in fresh water at 15C/58F, the speed is approximately 1410m/4625ft/sec, while saltwater at the same temperature it's approximately 1550m/5048ft/sec.
Hypercapnia
Excessive carbon dioxide
Buoyancy Formula = volume to be displaced
Extra weight(positive number)/water constant = volume to be displaced
Buoyancy Formula
Extra weight(positive number)/water constant= volume to be displaced
eardrum rupture
Failure to equalize, but pressure increases faster than fluids can fill the middle ear. The eardrum tears (bursts inward) due to pressure. Signs and Symptoms: Usually heals without complication, but requires medical attention to prevent infection and permanent damage because water contaminates the ear with organic matter and dirt.
True or false-divers succumb to depression sickness because in humans any amount of supersaturation of tissues with nitrogen will result in significant bubble formation.
False
Two divers may use a single dive computer provided they are careful to remain together and dive the exact same profile. A True B False
False
When a lift bag is ascending, you should position yourself immediately under it to watch the object's ascent. Choose your answer. A True B False
False
You need more weight when you dive in fresh water relative to salt water. Choose your answer. A True B False
False
true or false-divers succumb to depression sickness because in humans any amount of supersaturation of tissues with nitrogen will result in significant bubble formation.
False
Aluminum cylinders were introduced because aluminum is a stronger metal and enables higher working pressures than in steel cylinders True or False
False Aluminum is less subject to structural weakening due to corrosion
A scuba cylinder is filled to capacity at the surface. When this cylinder is used at a depth of 99 feet in the sea, the air within the cylinder is four times more dense than it was at the surface. True False
False Remember, a scuba cylinder is an inflexible container — it does not decrease in size as depth (pressure) increases. Therefore, the air within the cylinder is unaffected by the increasing water pressure outside the cylinder.
During a hydrostatic test a cylinder is placed in a water filled chamber. The cylinder is then filled with compressed air and the amount of expansion that occurs in the cylinder is measured by the water it displaces True or False
False The cylinder is filled with water and the amount of expansion that occurs in the cylinder is measured by the water it displaces
The condition described in the previous question (When breathing at depth, the tissues of a diver begin to take on additional gas pressure. If the diver remains at depth long enough, his tissues will again equalize with the ambient pressure) is referred to as supersaturation. True False
False We discussed previously that at the surface our tissues, or any liquid, can only hold an amount of gas equal to 1 atm. Regardless of how long we remain at 1 atm, our tissues can never achieve a gas tension of more than that amount. However, there is one way more gas can be absorbed — increase the pressure in contact with the tissues. At a greater ambient pressure the tissues will again equalize with the gas in contact with them. Therefore, as the pressure of the gas in contact with the tissues increases, so does the pressure within the tissues. But after time, if the ambient pressure is reduced, the reverse phenomenon will occur. More pressure or gas tension will exist within the tissue than the ambient pressure. In order words, a "pressure gradient" will exist in favor of the tissue. In this case the tissue is referred to as supersaturated, as it contains a higher gas tension that the ambient pressure. (Just as the gas tension within a can of soda is higher than the ambient pressure when the top is initially removed). For the diver this is an extremely important phenomenon to understand.
Because a diver's lung volume must remain constant regardless of the depth at which he breathes, the density of the air in the diver's lungs does not change even as he changes depth. True False
False When we breathe, we must breathe a "full" breath regardless of the pressure surrounding us. And, to be able to breathe, the external pressure must be equal to the air we are breathing. You can demonstrate this in a swimming pool using a short length of hose. Begin by breathing from one end of a one metre/three foot length of hose. Next, submerge just below the surface and breathe. As when using a snorkel, you will encounter relatively little breathing resistance. Now, while keeping one end of the hose above the water, submerge to about one metre/three feet of depth. You will quickly find that breathing becomes extremely difficult, if not impossible. Yet, the effect is caused by less than a 2 psi pressure differential between the surface air pressure and the water pressure surrounding your chest.
Predisposing factors to DCS
Fat, Age, Injury, Illness, Alcohol, Dehydration, Excess CO2, cold water, heavy exercise, altitude/flying, history of DCS
Open Circuit regulator has what parts
First stage Primary Second Stage Alternate Second Stage SPG Low Pressure Inflator Hose
Conshelf II
Five divers lived at 36 feet for one month in the Red Sea.
Charles law as it applies to scuba cylinders
For every 1C, scuba cylinder pressure will change .6 bar. For every 1F, scuba cylinder pressure will change 5psi.
Conshelf I
Founded by Jacques Cousteau, the project entailed two divers spending 1 week in 33 feet of water.
Capillaries
Gas exchange in blood happens here.
When using Enriched Air with up to 40% oxygen you should
Generally you may use standard scuba equipment Use of oxygen compatible lubricants is generally recommended follow all manufacturer recommendations regarding using their equipment with Enriched Air
If a diver exits the water in pressure group R, what would his new pressure group be after 51 minute surface interval?
H
When assisting a diver with oxygen toxicity that is convulsing underwater, you should: Choose your answer. A Try to buddy breathe with the diver B Handle as you would for any unresponsive diver underwater C Ascend and signal for assistance D None of the above.
Handle as you would for any unresponsive diver underwater
K valve
Has replaced J valve
On a hot day, a diver in a full suit is complaining of nausea. He is sweating and has cool, clammy skin. Is he suffering from Heat Stroke.. OR Heat Exhaustion?
He is suffering from Heat Exhaustion. Heat Stroke is worse than Heat Exhaustion. With heat stroke, there would be no more sweating, and the diver would have dry skin.So remember! Stroke is worse than Exhaustion.
Conduction
Heat transmission via direct contact. Affects Divers the most.
Conduction
Heat transmission via direct contact; a substance that easily transmits heat is a conductor. Water is an excellent conductor (20 times better than air).
Convection
Heat transmission via fluids.
Convection
Heat transmission via fluids; because a fluid becomes less dense and rises when heated, there is always cool water flowing over you during a dive.
What substance contained within the red blood cells aids in the transport of oxygen throughout the circulatory system? A Plasma B Cholesterol C Gammaglobulin D Hemoglobin
Hemoglobin
What substance contained within the red blood cells aids in the transport of oxygen throughout the circulatory system? Choose your answer. A Plasma B Cholesterol C Gammaglobulin D Hemoglobin
Hemoglobin
Gas Narcosis(Narked)
High levels of nitrogen(drunk on nitrogen)
lung over expansion injuries
Holding breath during ascent Diving with a chest cold Local blockage in the lungs due to loss of surfactant (due to smoking) Expanding air over-expands and causes lung rupture these can cause?
Dalton's law
I only partially understand him - PP
Charles Law
If pressure is kept constant, the volume increases as the temperature increases. If the volume is kept constant, the pressure increases when the temperature increases.
Boyle's Law (descriptive)
If temperature remains constant, the volume of a gas is inversely proportional to the absolute pressure.
Your buddy gives you a "cut throat" sign followed by pointing to his mouth. What action should you take in this circumstance? Choose your answer. A Immediately begin buddy breathing B Immediately provide your alternate air source to him C Check his SPG, then begin buddy breathing. If he experiences problems, then provide your alternate air source D Check the depth — if it is 12 metres/40 feet or less, signal him to make an emergency swimming ascent
Immediately provide your alternate air source to him
Henry A. Fleuss
In 1879, he developed first practical working scuba - an oxygen rebreather that did not differ much from modern oxygen rebreathers.
bradycardia
In cool water, ....... reduces circulation and is triggered by apnea (felt by cold on the face). Though this doesn't appear to reduce oxygen consumption in humans (it does in marine mammals). SLOWS HEART RATE
Trimix diving
In ideal conditions, divers use a mix of helium, nitrogen, and oxygen for dives deeper than 165 feet. No set depth limit, but newly certified trimix divers set depth limits to 245 feet (75 metres).
Technology-specific diving
Includes training with long-distance diver propulsion vehicles or CCRs
Identify the indicated component of a dive compass (set of 2 small boxes). A Lubber line B North needle C Bezel D Index mark
Index mark
Partial pressure
Individual pressure exerted by a component gas
Hypocapnia
Insufficient carbon dioxide. Can lead to shallow water blackout.
Louis de Corlieu
Invented first rubber fins for swimming in 1933.
What symptoms are likely if you were to rupture your ear drum?
It can cause severe vertigo
If a diver surfaces from a dive with a pressure group of U, what is his pressure group after 49 minutes on the surface?
J
Converting weight to volume
K / L
Converting volume to weight
L x K
Reflection
Light bouncing off of the surface of the water.
Diffusion
Light deflecting off of particles as it travels through water.
When the jugular veins found in the neck are constricted by an overly tight dry suit seal or wet suit hood, the following can occur: A Left arm pain B Lightheadedness C Dryness of the mouth D Vomiting
Lightheadedness
When the jugular veins found in the neck are constricted by an overly tight dry suit seal or wet suit hood, the following can occur: Choose your answer. A Left arm pain B Lightheadedness C Dryness of the mouth D Vomiting
Lightheadedness
Identify the indicated component of a dive compass (Line w/ no markings). A North needle B Lubber line C Index mark D Bezel
Lubber line
Compared to the Navy table the RDP has lower ___________ to match doppler data
M-values
When making a Controlled Emergency Swimming Ascent, what should the diver do regarding his ascent rate? Choose your answer. A Ascend at whatever rate is comfortable B Because this is an emergency, ascend as fast as possible C Ascend no faster than his slowest air bubbles D Maintain a normal ascent rate (not in excess of 18 metres/60 feet per minute)
Maintain a normal ascent rate (not in excess of 18 metres/60 feet per minute)
Vital capacity
Maximum volume that you inhale after total expiration
When a diver's ears experience a squeeze while descending, which part of the ear is most affected? A Inner ear, vestibular canals and cochlea B Middle ear, eardrum and eustachian tube C Outer ear canal D Oval window, ossicles and round window
Middle ear, eardrum and eustachian tube
When a diver's ears experience a squeeze while descending, which part of the ear is most affected? Choose your answer. A Inner ear, vestibular canals and cochlea B Middle ear, eardrum and eustachian tube C Outer ear canal D Oval window, ossicles and round window
Middle ear, eardrum and eustachian tube
hypocapnia
NOT ENOUGH carbon dioxide Too little carbon dioxide may interrupt the normal breathing cycle because carbon dioxide actually stimulates breathing. Causes: Excessive hyperventilation Symptoms: Light headedness, Shallow water blackout>, Visual disturbances, Anxiety, Pins and needles, Muscle cramps especially in hands and feet
NAUI
National Association of Underwater Instructors
Polar Structure of Water
Negative charge at the oxygen end and slight positive charge at the hydrogen end; the polarity causes water molecules to create a hydrogen bond (or polar bond) with each other
Type 2 DCS
Nervous system; immediately life threatening
Composition of Air
Nitrogen - 79 Oxygen - 21
Composition of Air
Nitrogen - 79.084% Oxygen - 20.946% Argon - 0.934% Carbon Dioxide - .033%
An/A _________________ depth gauge works by using Boyle's law. A bourdon tube B analog C pressure transducer activated D None of the above.
None of the above.
Divers on a live-aboard complete three dives in one day. Their dive profiles are: first dive - 100 feet for 16 minutes, surface interval - 1 hour 10 minutes; second dive - 55 feet for 36 minutes, SI - 2 hours 30 minutes; third dive - 33 feet for 55 minutes. What is their pressure group after the third dive?
O
Divers on a live-aboard complete three dives in one day. Their dive profiles are: first dive - 30.48m for 16 minutes, surface interval - 1 hour 10 minutes; second dive - 16.764m for 36 minutes, SI - 2 hours 30 minutes; third dive - 10m for 55 minutes. What is their pressure group after the third dive?
O
What is a diver's pressure group after surfacing from a dive to 29 feet for 77 minutes?
O
What is a diver's pressure group after surfacing from a dive to 8.8392m for 77 minutes?
O
Water magnification ratio
Objects underwater are magnified so they appear closer by a ratio of about 4:3 for their actual and apparent distances; an object may be 25% closer and 33% larger than it actually is.
O / W - D
Objects weight / Water [1.03 or 1.0] - Displacement - used to determine buoyancy of an object - depth doesn't matter
Isobaric counterdiffusion
Occurs when a diver breathes a slowly diffusing gas (e.g. nitorgen) while surrounded by a rapidly diffusing gas (e.g. in a helium-filled dry suit). It can also occur if you breathe a rapidly diffusing gas while decompressing a slowly diffusing gas.
vertigo
Occurs when the eardrum ruptures and cold water on the vestibular canals cause momentary loss of sense of direction and dizziness
J valve
Old school valve that would click to let you know you're entering reserve air
Ionic bonding
One atom takes an electron from another atom to complete its outer shell (e.g. NaCl)
Pilot valve
Only appears in 2nd stage
_____________ scuba systems are the most common type of recreation scuba equipment, are easy to use and maintain, and vent exhaled gases directly into the water. A Rebreather B Open circuit
Open circuit
_____________ scuba systems are the most common type of recreational scuba equipment, are easy to use and maintain, and vent exhaled gases directly into the water.
Open circuit - Open circuit scuba is the most common type of recreational equipment because it's easy to use and maintain. When you inhale, you breathe in from a compressed gas cylinder and when you exhale, your breath vents into the water and bubbles to the surface.
What are the most likely problems that can occur underwater? (check all that apply) Choose your answer. A Overexertion B Running low on or out of air C Regulator free flow D Loss of buddy
Overexertion Running low on or out of air Regulator free flow
Partial pressure and oxygen toxicity
Oxygen becomes toxic when partial pressure exceeds 1.4 bar/ata
An 80 cubic foot scuba cylinder is filled to 3225 psig at an ambient temperature of 78° F. What will the cylinder pressure be if the cylinder is used in water temperature of 44° F? (Assume 1atm = 15 psi) a. 2885 psig b. 3020 psig c. 3035 psig d. The answer cannot be determined from the data provided.
P1 x V1/T1 = P2 x V2/T2. Where P = pressure, V = volume and T = temperature. As we are dealing with a scuba cylinder, its volume will remain unchanged. Therefore, we can ignore the volume variable altogether, restructuring the equation as follows: P1/T1 = P2/T2 Next, let's determine what we know from the problem: -The pressure the cylinder is filled to is 3225 psig (P1), and it asks us to determine what the pressure will become (P2). But, these are not yet proper variables to plug into the equation. To predict the behavior of gases we must always work in absolute terms. So, we must add 15 psi to the 3225 psi for 3240 psia. This then becomes the quantity to insert into the equation. - The temperature of the cylinder is 78°F, and it will be used in 44°F water. But, as stated before, we must work in absolute terms. With temperature, this means working in terms of absolute zero. Readings in degrees Fahrenheit must be converted into degrees Rankin. To convert a Fahrenheit reading into a Rankin reading, just add 460°. Therefore, 78°F, becomes 538°R (T1); and 44°F, becomes 504°R (T2). Now we can plug the values into the formula: 3240 ÷ 538 = X ÷ 504, where "X" is the unknown. This can be rearranged to become: 504 x 3240 ÷ 538 = X And by doing the simple arithmetic, we determine that: 3035 psia = X. But this still is not the correct answer since 3035 psia is absolute pressure. We need to subtract 15 psi from 3035 psi to arrive at the cylinder's real pressure. Therefore, 3035 - 15 = 3020 psig.
Pressure/volume change formula
P1xV1=P2xV2
PADI Master Scuba Diver
PADI Rescue Diver who has earned 5 specialties.
Boyle's Law (mathematically)
PV = K
General Gas Law
PV = nRT
Type 1 DCS
Pain only; not immediately life threatening
Phil Nyutten
Patented oil-filled rotary joint for hard suits, which becomes the basis of the Newt Suit.
Avogadro's number
Physicists determined that a 0C and 1 bar/ata, 22.4 litres of gas consists of 602.2 billion trillion molecules (6.022 X 10^23) - referred to as one mole.
A buddy team exits the water. Both divers are using dive computers. After a short surface interval, they plan another dive to 18 metres/60 feet. One device allows 38 minutes of bottom time at 18 metres/60 feet, the other allows only 32 minutes. Based on this information how should they plan their dive? A Plan a maximum bottom time of 38 minutes because computers are intentionally designed to be more conservative than dive tables. B Plan a maximum bottom time of 32 minutes because computers are intentionally designed to be more conservative than dive tables. C Plan a maximum bottom time of 38 minutes but be sure to make a safety stop before surfacing. D Plan a bottom time of somewhat less than 32 minutes and make a safety stop before surfacing.
Plan a bottom time of somewhat less than 32 minutes and make a safety stop before surfacing.
Surface Tension of Water
Polar bonds between water molecules make the water surface slightly cohesive, so it resists penetration and separation.
Dead air-space/dead space
Portion of your tidal volume that plays no direct part in gas exchange (i.e. sinuses, trachea, and bronchi). With SCUBA equipment, dead air space includes snorkel, regulator or other breathing equipment.
Buoyancy - what happens when a object is positive/negative.
Positive number - object sinks Negative number - object floats
Buoyancy cont.
Positive number - object sinks Negative number - object floats
Gas Tension
Pressure exerted within a liquid by a particular gas in solution
Why do you feel discomfort in your ears while descending?
Pressure pushing your eardrum and surrounding tissues inwards.
Pressure (related to diving)
Pressure we experience from the atmosphere and while diving is the force of gravity acting on air and water. Atmospheric pressure is the weight of the air above you and water pressure is the weight of the water above you - the water is pulled down by gravity.
Identify the component of an open circuit scuba regulator indicated in the photograph (black breathing device). A Alternate air source B Low pressure inflator C Primary second stage D First stage
Primary second stage
PADI
Professional Association of Diving Instructors; established in 1966
John Scott Haldane
Published first dive tables in 1908.
A diver completes a multilevel dive with the following dive profile: 115 feet for 6 minutes, then 78 feet for 10 minutes, then 44 feet for 21 minutes. What is the diver's pressure group upon surfacing from the dive?
R
Three current forms of the RDP
RDP Table eRDPml Enriched Air RDP Table
The fundamental function of the first stage of an open circuit regulator is to
Reduce the high pressure delivered by the cylinder to an intermediate pressure
_________ in your brain monitor rising carbon dioxide levels in the body which then triggers the breathing cycle. A Reflex respiratory centers B Carotid-sinus reflex C Hemoglobin D Diaphragm
Reflex respiratory centers
_________ in your brain monitor rising carbon dioxide levels in the body which then triggers the breathing cycle. Choose your answer. A Reflex respiratory centers B Carotid-sinus reflex C Hemoglobin D Diaphragm
Reflex respiratory centers
Turbidity
Relative concentration of suspended particles
If a diver exceeds the no decompression limit by six minutes, and doesn't realize the oversight until after surfacing, what is the recommended procedure?
Remain on the surface, rest and be monitored for signs/symptoms of decompression sickness; wait at least 24 hours before diving again
Visual reversal
Results from visual processing and how your brain interprets what it sees depending upon water clarity, contrast and the amount of light; turbidity can make things look farther away than they actually are
What is a diver's pressure group after a dive to 64 feet for 41 minutes?
S
Steel vs aluminum tanks
STEEL - heavier - greater working pressure (some) - more prone to rust - buoyancy change from full->low is less b/c it's heavier - some tec diving advantages - round bottom ALUMINUM - last longer - easier to clean - flat bottom
John Cronin
Scuba manufacturer rep who co-founded PADI
The knot in the illustration is a ______. Choose your answer. A bowline B half-hitch C sheet bend D None of the above.
Sheet bend
What is the name given to tiny bubbles of Nitrogen that can found in a divers blood after a dive, although no symptoms can be found ?
Silent Bubbles.
Bradycardia
Slowing down of heart rate
Tachycardia
Speeding up of heart rate
What step is not part of a primary assessment? Choose your answer. A AB-CABS B Shock Management C Splinting D Serious Bleeding Management
Splinting
The (+) designation that appears on ___________ cylinder denotes that the cylinder may be overfilled to ______________ beyond its working pressure.
Steel / 10% - Some steel cylinders have a plus (+) sign after the date of the last hydrostatic test. These steel cylinders may be filled to 10 percent above the listed pressure.
3AA stamp on cylinders is for
Steele Chrome alithilum steele
Heat stroke is characterized by which of the following signs and symptoms: A Strong, rapid pulse and hot, flushed skin B Weak pulse and clammy skin C Vasoconstriction D Dilated capillaries
Strong, rapid pulse and hot, flushed skin
Heat stroke is characterized by which of the following signs and symptoms: Choose your answer. A Strong, rapid pulse and hot, flushed skin B Weak pulse and clammy skin C Vasoconstriction D Dilated capillaries
Strong, rapid pulse and hot, flushed skin
_____________ after a dive refers to nitrogen pressure in the body tissues being higher than the surrounding pressure. A Gas narcosis B Hypoxia C Supersaturation D Inert gas absorption
Supersaturation
_____________ after a dive refers to nitrogen pressure in the body tissues being higher than the surrounding pressure. Choose your answer. A Gas narcosis B Hypoxia C Supersaturation D Inert gas absorption
Supersaturation
Heat vs. Temperature
Suppose you have a large mass and a small mass of water, both with the same temperature. Although the temperature is the same and it's the same substance, the large mass will have considerably more heat because there are many, many more molecules in motion within it.
Accelerated decompression
Switching to gas blends high in oxygen, or pure oxygen, to shorten the required decompression time
CO2 is involved in metabolic processes (T/F)
T
you lose more heat breathing air at depth (T/F)
T
hypercapnia
TOO MUCH carbon dioxide Causes: Shallow rapid breathing, Skip breathing, Overexertion, or a combination of these. In very rare cases air supply may be high in carbon dioxide. Respiratory drive impaired by head injury or drugs Trauma which causes respiratory muscle weakness Signs and symptoms:Headache, Accelerated breathing. , Confusion, Loss of consciousness, early- flushed skin due to vasodilation, muscle- twitching, headache, Progressing to disorientation, panic, convulsions, loss of consciousness..
When breathing at depth, the tissues of a diver begin to take on additional gas pressure. If the diver remains at depth long enough, his tissues will again equalize with the ambient pressure. True False
TRue This is merely a logical extension of what we have been exploring. When the diver breathes air underwater, he is breathing gas at a higher pressure than at the surface. Therefore, the pressure of the gas in contact with his tissues increases. As the gas pressure increases so must the gas tension within the tissues. Conversely, when the gas in contact with the tissues decreases, the gas tension within the tissues also decreases. This phenomenon is called decompression.
Which of the following statements best describes the relationship between pressure group designations on the Recreational Dive Planner and pressure group letters used on other dive models?
The RDP pressure group designations are not interchangeable with the pressure group letters on other dive tables
Henry's Law
The amount of gas that dissolves into a liquid at a given temperature is directly proportional to the partial pressure of that gas.
Approximately how much air must be added to a lifting device to bring a 600 kilogram object to the surface? The object lies in 30 metres of fresh water. Choose your answer. A 620 litres B 600 litres C 580 litres D The answer cannot be determined from the data provided.
The answer cannot be determined from the data provided.
During a hydrostatic test a scuba cylinder is generally pressurised to __________ of it's working pressure.
The cylinder is pressurized to typically 5/3 or 3/2 the cylinder's listed pressure.
The density and elasticity of a medium has what effect upon the transmission of sound? Choose your answer. A The denser and more elastic the medium, the better sound is transmitted. B The denser and more elastic the medium, the poorer sound is transmitted. C The denser and more elastic the medium, the less sound can be transmitted. D Density and elasticity of a medium has no effect upon the transmission of sound.
The denser and more elastic the medium, the better sound is transmitted.
Sound transmission
The elasticity of a substance, not really the density, that allows it to transmit sound more effectively. Many dense materials have superior elasticity, which is why it's a general rule of thumb is that sound travels better through denser materials; however, it is not universal.
Absorption
The further underwater light is the more it is absorbed. Results in color loss.
Temperature
The measure of the average degree of molecular motion within the mass; measured in Celsius, Fahrenheit, Rankine, and kelvins.
What part of the ear is most affected while descending?
The middle ear
What is total bottom time
The sum of residual nitrogen time and actual bottom time of a repetitive dive
Absolute zero
The temperature at which there is no molecular motion. Nothing can be colder than 0 K or 0 R. Absolute 0 on Kelvin scale is -273C and absolute value on Rankine scale is -460F.
What is bottom time?
The time from the beginning of the descent until beginning a direct, continuous ascent to the surface or safety stop
Dalton's Law
The total pressure exerted by a mixture of gases is equal to the sum of the pressures of each of the different gases making up the mixture - each gas acting as if it alone were present and occupied the total volume.
Solubility in Water
The universal solvent; molecules begin to interact according to their polarity. Ionic substances are ripped apart and remain suspended within water Nonpolar molecules don't readily dissolve in water. Oils and fats are nonpolar.
If a balloon and a scuba tank are both filled with air and placed outdoors in direct sunlight on an extremely hot day, what will happen to each?
The volume of the balloon will increase and the pressure in the tank will increase.
If a balloon and a scuba tank are both filled with air and placed outdoors in direct sunlight on an extremely hot day, what will happen to each? Choose your answer. A The volume of the balloon and tank will both increase. B The volume of the balloon will decrease and the pressure in the tank will decrease. C The volume of the balloon will increase and the pressure in the tank will increase. D The pressure in the balloon and tank will both decrease.
The volume of the balloon will increase and the pressure in the tank will increase.
How do skin divers prepare for a breath hold dive?
They use deep-stomach breathing
What Type of Valve is this.
This is a DIN valve. The sealing o-ring mounts on your regulator and screws into the DIN valve.
Approximately how mutch denser is the air a diver breathes at a depth of 20 metres/66 feet as compaired to the serface?
Three times as dense.
If all our tissues are essentially comprised of water, why don't they all absorb and eliminate nitrogen at about the same rate?
Tissues have different densities. like Bone and skin. blood supply differs among tissues. tissues have more blood supply will have more gas delivered and eliminated.
if all our tissues are essentially comprised of water, why don't they all absorb and eliminate nitrogen at about the same rate?
Tissues have different densities. like Bone and skin. blood supply differs among tissues. tissues have more blood supply will have more gas delivered and eliminated.
Why do you need to know the maximum depth of a dive and how long you've been underwater? A To avoid decompression sickness and remain within your planned depth and time limits B So you can ascend at the appropriate rate C To avoid air embolism D All of the above.
To avoid decompression sickness and remain within your planned depth and time limits
Louis Boutan
Took first underwater photographs by a diver in 1892.
Heat
Total kinetic energy of the molecules within a given mass; measured in joules, calories, or BTUs (British Thermal Units).
Thermocline
Transition between layers of different temperatures
A dive computer constantly tracks your depth and time on a dive and then applies the information to a mathematical model to compute the theoretical nitrogen in your body? True or False
True
Before using your computer for the first time, you should read the manufacturer's instructions. A True B False
True
During a hydrostatic test a scuba cylinder is placed in a water-filled chamber. The cylinder is then filled with water. As the water pressure within the cylinder is increased, the amount of expansion that occurs in the cylinder is measured by the amount of water that is displaced. O True O False
True
During a hydrostatic test a scuba cylinder is placed in a water-filled chamber. The cylinder is then filled with water. As the water pressure within the tank is increased, the amount of expansion that occurs in the cylinder is measured by the amount of water that is displaced. A True B False
True
One advantage of an open circuit demand valve regulator is that it avoids carbon dioxide buildup by reducing dead air spaces. A True B False
True
The use of oxygen compatible lubricants, O rings, and other materials as appropriate during servicing is generally recommended. True or False
True
True or False - Hypoxia results when the divers carbon dioxide level cannot accumulate to a level high enough to stimulate breathing before the tissues consume the available oxygen.
True
Typically, aluminum cylinders have higher working pressures so they hold comparable or slightly more air than steel cylinders. A True B False
True
When using Enriched Air have your regulator service annually or as stipulated by the manufacturer. True or False
True
You should not turn off your computer or remove the batteries between dives because that would cause it to lose any memory of previous dives which could cause it to calculate repetitive dives incorrectly and create an unacceptable DCS risk. True or False
True
A cylinder that has permanent expansion above specified standards fails the test and is taken out of service, while a cylinder that passes the test has a new hydrostatic date stamped onto the cylinder neck. O True O False
True - For safety reasons, cylinders that fail hydrostatic tests are destroyed and those that pass get a new hydrostatic date.
A cylinder valve's high pressure seat lets gas flow or stops it from flowing as the on-off knob is turned. O True O False
True - The high pressure seat is inside the valve and lets gas flow or stops it from flowing as the on-off knob is turned.
Cave diving
Typically shallower; main danger is far from air/light source and stirring up silt.
Sidemount diving
Typically used in cave diving; divers ear separate cylinders on one or both sides, which allows for movement through very small areas more easily.
DOT
US made tank marking
All rebreathers recycle _____________ into the water. instead of allowing them to be wasted
Usable Gasses - All rebreathers recycle usable exhaled gases instead of allowing these gases to be wasted into the water like open circuit scuba.
Advanced Open Water program students complete three dives in one day. Using the following dive profiles calculate their pressure group upon surfacing from the last dive: Dive 1 95 feet for 17 minutes, SI 53 minutes, Dive 2 56 feet for 28 minutes, surface interval - 92 minutes; Dive 3 - 46 minutes for 52 minutes.
V
Central nervous system toxicity symptoms
VENTID: visual disturbances (tunnel vision, blurring), ear disturbances (ringing, music), nausea, twitching (especially in face), irritability and dizziness (vertigo)
Tidal volume
Volume of gas you inhale and exhale during normal breathing
Buoyancy formula = weight of water displaced
Volume x water constant = weight of water displaced
Density Stratification
Water forms into layers of differing densities. Descending from one layer into another often results in an abrupt temperature drop. Dissolved substances also increase water density and cause stratification.
Diffusion
Water scattering and deflecting light
Water and heat capacity
Water's polar structure gives it one of the highest heat capacities of all naturally occurring substances. When heating water, a significant amount of heat energy must first break the bonds before heat can increase the kinetic energy (temp) of the water molecules. For the same reason, water also has a high heat of vaporization and high latent heat of fusion ( when water freezes, it releases large quantities of heat). High heat capacity is critical for moderating the world's climates (e.g. carrying warm water from equatorial regions to the cooler regions closer to the poles).
Buoyancy formula = positive/negative buoyancy
Weight of object - weight of water = positive/negative buoyancy
Refraction
When light passes from one medium to another.
A diver completes a 55 minute dive to 50 feet and after waiting for 45 minutes on the surface makes a second dive to 46 feet for 45 minutes. What is the diver's pressure group after the second dive?
X
Based on broadly accepted international dive community practices enriched air cylinders should have the following markings/colors/tags
Yellow cylinders should have a 4" green band at the shoulder with enriched air or nitrox should have a visual inspection sticker should have a sticker to indicate whether it is oxygen service rated should have a content sticker or tag
what are Two basic types of cylinder valves
Yolk or DIN
You shouldn't use __________ as a lifting device because it can cause a hazardous runaway ascent. Choose your answer. A a lift bag B an alternate air source C a boat anchor D a BCD
a BCD
A diver experiencing gas narcosis may have: Choose your answer. A cherry red lips and nail beds. B labored breathing and complain of headache and nausea. C a false sense of security at depth and display distracted behavior. D numbness and tingling, or pain in the joints and limbs.
a false sense of security at depth and display distracted behavior
A diver experiencing gas narcosis may have: A cherry red lips and nail beds. B labored breathing and complain of headache and nausea. C a false sense of security at depth and display distracted behavior. D numbness and tingling, or pain in the joints and limbs.
a false sense of security at depth and display distracted behavior.
The pictured search pattern is called a: Choose your answer. A a parallel B an expanding square C a jack-and-move D a jackstay
a jackstay
Smoking and chronic lung obstructions are factors that may contribute to: Choose your answer. A decompression sickness. B carotid sinus reflex. C nitrogen narcosis. D a lung overexpansion injury.
a lung overexpansion injury
Smoking and chronic lung obstructions are factors that may contribute to: A decompression sickness. B carotid sinus reflex. C nitrogen narcosis. D a lung overexpansion injury.
a lung overexpansion injury.
Weight
a measure of the force of gravity acting upon mass
If a diver does three dives a day for three days, what is the minimum time the diver should wait after the last dive before flying commercial jet airliner according to the flying after diving recommendation?
a minimum of 18 hours is suggested
Safety stop
a pause in ascent, usually at 15 feet (5 metres) that is not required but made for added conservatism to further reduced chances of decompression sickness
Decompression stop
a pause or pauses in ascent at a specific depth and time to allow the body to release dissolved gas and avoid decompression sickness
Severe lung squeeze can occur in shallow depth in which of the following
a skin diver descends with his lungs nearly empty.
Insulator
a substance that resists conduction; air is a good insulator which is why dry suits insulate you better than wet suits
Where does gas exchange in the body occur ? a) Between the pulmonary capillaries and the alveoli b) Between the pulmonary arteries and the bronchi c) In the hypothalamus d) There is no gas exchange in the body
a) Between the pulmonary capillaries and the alveoli
The most serious risk of diving with Enriched Air (Nitrox) is: a) CNS oxygen toxicity b) Pulmonary oxygen toxicity c) Hypoxia d) Mammalian dive reflex
a) CNS oxygen toxicity
Excessive hyperventilation (more than 3 or 4 breaths) before a breath hold dive can cause: a) a diver to black out in shallow water without warning b) hypercapnia c) carotid sinus reflex d) an excessive urge to breathe in deep water
a) a diver to black out in shallow water without warning Hyperventilating (3 to 4 times) can increase breath hold time. Doing so reduces circulatory carbon dioxide so it takes longer to accumulate enough to stimulate breathing. Excessive hyperventilation may lead to shallow water blackout.
To avoid CNS oxygen toxicity: a) don't exceed an oxygen partial pressure of 1.4 ata b) don't exceed an oxygen partial pressure of 2.0 ata c) follow the oxygen exposure limits on the DSAT Oxygen Exposure Table d) None of the above
a) don't exceed an oxygen partial pressure of 1.4 ata Central nervous system oxygen toxicity: involves nervous system reactions to oxygen exposure and tends to be unpredictable. It is the more serious toxicity and can cause a diver to drown. Only occurs if breathing PO2 above 1.4bar.
As a diver ascends from a dive at depth, nitrogen pressure in tissues is _____________ the surrounding pressure. a) higher than b) lower than c) equal to d) unaffected by
a) higher than
What is the name of the lung overexpansion injury that occurs when a lung collapses? a) pneumothorax b) subcutaneous emphysema c) air embolism d) convulsion
a) pneumothorax
If a diver shows signs of heat stroke: a) remove the divers exposure suit, put the diver in a cool environment and contact emergency medical aid b) put the diver in a warm environment and contact emergency medical care. c) have the diver seek warmth and wear insulating clothing d) remove the diver's exposure suit, put the diver in a cool environment and have the diver rest and drink non alcoholic fluids.
a) remove the divers exposure suit, put the diver in a cool environment and contact emergency medical aid
Shallow water blackout can occur if a breath hold diver a) stays too long underwater b) ascends too fast c) doesn't hyperventilate on the surface d) doesn't stay attached to the safety line
a) stays too long underwater
The primary purposes of the respiratory and circulatory system are: a) to supply the body tissues with oxygen and remove carbon dioxide b) to regulate the absorption and the release of nitrogen c) both a and b d) none of the above
a) to supply the body tissues with oxygen and remove carbon dioxide
If a diver starts a dive warm and with normal circulation but then gets cold during the dive, circulation: a) to the extremities reduces, slowing elimination of nitrogen b) generally speeds up, raising the diver's heart rate c) stays the same, but heart rate slows down d) becomes erratic, causing heart tremors
a) to the extremities reduces, slowing elimination of nitrogen
A ruptured ear drum may immediately cause ____________underwater and may also lead to infection due to water entering the _______________ a) vertigo, middle ear b) euphoria, inner ear c) hypothermia, middle ear d) vertigo, inner ear
a) vertigo, middle ear
In all but the warmest water, even with exposure protection a diver loses heat faster than the body can generate it. This is primarily because: a) water absorbs heat significantly faster than air b) the diver loses heat the each breath of cool gas c) divers always shiver a little d) most hear loss is through the face
a) water absorbs heat significantly faster than air
A balloon is filled with 2 cubic feet of air at 100 feet of seawater. What will be the approximate volume of the balloon if it is taken to a depth 300 feet? a. 0.8 cubic feet b. 0.3 cubic feet c. 0.67 cubic feet d. The answer cannot be determined by the data provided.
a. 0.8 let's assume that 100 feet is close enough to 99 feet to use the pressure of 4 ata. Next, let's find out how much pressure is exerted by 300 feet of depth. By dividing 33 into 300 we determine that we are at a pressure of about 9 atm gauge or 10 ata. (Actually, 297 feet is 10 ata, but close enough). We now have a different way of expressing the problem. "A balloon is filled with 2 cubic feet of air at 4 ata. What will be the approximate volume of the balloon if it is taken to 10 ata?" By applying our rule of taking the quantity (2 cubic feet) to the surface from 4 ata (100 feet), we discover that it will expand to 8 cubic feet. Now all that remains is returning the quantity (8 cubic feet) to 10 ata, or 8/10. Reduce the fraction or divide and the answer is .8 cubic feet.
A scuba cylinder is accidentally filled with 1% carbon monoxide. If a diver breathes air from this cylinder at a depth of 100 feet of seawater, approximately what percentage of carbon monoxide will he be breathing? 1% 2% 3%
a. 1% Once a cylinder is filled, the percentages of gases within it cannot change (unless more air is added). Therefore, if only 1% of a gas is put into a cylinder, no more or less than 1% can be in the cylinder regardless of the pressure to which the cylinder is subjected. It may be noted however, that the partial pressure of each gas breathed at depth does increase.
From the previous question (Assume that the atmosphere contains 80% nitrogen), the total gas pressure within our tissues is: 1.0 ata 0.8 ata 0.2 ata The answer cannot be determined from the data provided. Submit
a. 1.0 ata As the absolute pressure in contact with our tissues is 1.0 ata, then the absolute gas tension within our tissues must be 1.0 ata.
In a mixture of air comprised of 20% oxygen and 80% nitrogen, at an ambient pressure of 15 psia what is the partial pressure of oxygen? a. 3 psia b. 6 psia c. 12 psia d. 15 psia
a. 3psia 15 x .20 = 3 The partial pressure of a gas is dependent upon two variables: the absolute pressure, and the percentage of the gas in question. In this case, we are told to assume the absolute pressure is 15 psia, and the gas —oxygen — comprises 20% of the total. So, by simply multiplying the absolute pressure (15 psia) times the percentage of oxygen (20%), we find that the partial pressure is 3 psia (15 x .20 = 3). The English scientist John Dalton summarized his experience with the behavior of gases within mixtures via Dalton's Law, which states, "the total pressure exerted by a mixture of gases is equal to the sum of the pressure of each of the different gases making up the mixture — each gas acts as if it alone were present and occupied the total volume."
A balloon containing 10 cubic feet of air at 25 feet of seawater is taken to a depth of 85 feet. What will be the exact volume of the balloon upon reaching 85 feet? a. 4.91 cubic feet b. 2.94 cubic feet c. 1.95 cubic feet d. The answer cannot be determined from the data provided.
a. 4.91 First, we must turn the data given to us expressed as "depth" into expressions of "pressure." From the previous question on pressure, we should be able to determine that 25 feet of seawater exerts 25.82 psia (absolute): (25 ft x .445 psi/ft) + 14.7 psi = 25.82 psia. And, that 85 feet of seawater exerts 52.52 psia: (85 ft x .445 psi/ft) + 14.7 psi = 52.52 psia.Next, we need the equation: P1 X V1 = P2 X V2. As we now have three of the four variables provided to use, the rest is merely a matter of arithmetic — after we plug in the variables: The first pressure variable (P1) is 25.82 psia (25 feet of depth). P1 = 25.82 psiaThe second pressure variable (P2) is 52.52 psia (85 feet of depth). P2 = 52.52 psiaThe first volume variable (V1) is given as 10 cubic feet. V1 = 10 cubic ftThe second volume variable is what we are trying to find. By arranging the data according to the original equation (P1 x V1 = P2 x V2), we determine: 25.82 x 10 = 52.52 x "X", where "X" is the unknown variable. In order to get the unknown variable alone, we divide each side by 52.52 or 258.2 ÷ 52.52 = 52.52 ÷ 52.52 x X.The 52.52 ÷ 52.52 equals 1, and 1 times any quantity equals itself (1 x X = X). Therefore, the 52.52 ÷ 52.52 is irrelevant and cancels out. So, we are left with: 258.2 ÷ 52.52 = XAnd by dividing 258.2 by 52.52, we determine that: X = 4.91 cubic feet.
Divers are most affected by what form of heat transmission? a. Conduction b. Convection c. Radiation d. All of the above are equally important Submit
a. Conduction Conduction most affects divers. Conduction refers to the transmission of heat via direct contact. Convective and radiant transmission of heat are relatively unimportant to divers.
___________ is a substance contained within the _____ blood cells that aids in the transportation of oxygen throughout the system. a. Hemoglobin / red b. Plasma / red c. Cholesterol / red d. Hemoglobin / white
a. Hemoglobin / red
Refraction is caused by the process of: a. Light traveling at different speeds as it passes through different substances. b. Water absorbing various wave lengths of light beginning at the red end of the spectrum. c. The changing speed of light due to sunspot activity. d. Light traveling at the same speed as sound once it enters water and encounters resistance.
a. Light traveling at different speeds as It passes through different substances. Refraction is caused by the process of light traveling at different speeds as it passes through different substances. As light passes through transparent substances of differing densities, the speed at which it travels changes. This change of speed causes the light wave to bend or "refract."
The ______ ear is the part most affected by changes in pressure. a. Middle b. Soft tissue in the c. Outer d. Inner
a. Middle
The density and elasticity of a medium has what effect upon the transmission of sound? a. The denser and more elastic the medium; the better sound is transmitted. b. The denser and more elastic the medium; the poorer sound is transmitted. c. The denser and more elastic the medium; the less sound can be transmitted. d. Density and elasticity of a medium has no effect upon the transmission of sound.
a. The denser and more elastic the medium; the better sound is transmitted. The denser and more elastic the medium, the better sound is transmitted. Sound results from vibrations. Air cannot conduct vibrations efficiently, so sounds don't tend to travel very well in air. However, in denser media - steel or water, for example - vibrations can be transmitted quite efficiently. The molecules of these media are much closer together than in air, making it easier to transmit vibrations. Also, if sound travels so well in water, one may ask, why can't humans talk in that environment? The problems stems from the inability to initially produce sound while underwater. Human vocal cords must operate in an air environment.
If the pressure within the pot in the previous question (A glass of water has been placed in a vacuum for several days. It no longer contains any dissolved gas within it. it is then placed in a pressure pot and pressurized to 2 ata for several days) is increased, the pressure of the gas within the liquid will: increase. decrease. remain unchanged. The answer cannot be determined from the data provided.
a. increase Henry's Law is a direct relationship. Therefore, if one factor increases, so will the other. Think of it in terms of everyday experience. When you uncap a bottle of soda, the pressure of the carbon dioxide decreases because the pressure of the gas in contact with the soda decreased. Eventually, the gas in the soda will equal the pressure of the surrounding air. In other words, the soda will "go flat." If the phenomenon was an inverse relationship (one variable increases if one decreases), the soda would actually have to take on more gas as it sat open. This, of course, violates common sense, and our own practical experience.
Divers have difficulty determining the direction of sound underwater because: a. There is an insufficient delay between the sound striking one ear before the other. b. Water filling the ear canal reduces the ear's sensitivity to sound. c. The wet suit hood makes it difficult to perceive sound as accurately as on land. d. Sound waves travel less efficiently underwater.
a. there is an insufficient delay between the sound striking one ear before the other. Divers have difficulty determining the direction of sound underwater because there is an insufficient delay between the sound striking one ear before the other. Because of the increased speed of sound underwater, the human brain is unable to perceive the delay from one ear to the other. The brain interprets the sound as coming from all directions equally. Therefore, the origin of sound cannot be determined well.
As depth increases underwater colors disapear due to water's ability to _____ light. The first color to disappear is _____.
absorb / red
Real gas law
accounts for individual variation due to differences in gas molecules
if your diving above 1000 feet wait 6 hours before diving or
add 2 pressure groups to each 1000 feet to your planning
Enriched Air cylinder markings are generally
agreed upon and accepted by the broad international dive community
What is the most serious lung overexpansion injury? A mediastinal emphysema B air embolism C pneumothorax D carotid sinus reflex
air embolism
What is the most serious lung overexpansion injury? Choose your answer. A mediastinal emphysema B air embolism C pneumothorax D carotid sinus reflex
air embolism
The most serious form of lung over-expansion injury is an _______________ because air bubbles enter the_____________________.
air embolism / arterial circulation
Generally, you should use your ______________ to fill a lift bag. Choose your answer. A primary second stage B buddy's primary second stage C alternate air source D both a and c
alternate air source
This photo shows where the ___________ should be located. Choose your answer. A SPG B Dive computer C Knife D Alternate air source
alternate air source
3AA
aluminum
Carlorie
amount of heat require to raise one gram of water one degree celsius
Joule
amount of heat required to raise one gram of air one degree Celsius
Why were the WX YZ rules created for the RDP
analysis found that a compartment slower than 60 minutes could could control a repetitive dive for a small portion of no stop dives involving long shallow multiple dive profiles
burst disc is replaced
annually
Visually inspect scuba cylinders when
annually replace O rings and inspect valves
barotrauma
any sort of pressure related injury like in the ear.
Work
application of a force through a distance
The term "silent bubbles" refer to bubbles that:
are so small they do not cause signs and symptoms of decompression sickness.
the term "silent bubbles" refer to bubbles that:
are so small they do not cause signs and symptoms of decompression sickness.
Which of the following lung over expansion injuries is most likely to result in stroke like symptoms? a) air embolism AGE b) Pneumothorax c) Mediastinal emphysema d) Subcutaneous emphysema
arterial gas embolism AGE
if you accidentally descend past 130 feet you should immediately
ascend to 15 feet, make emergency decompression stop for 8 minutes and do not dive again for 6 hours
a balanced regulator valve is designed so that the air pressure neither
assists or resists the opening of valves allows breathing that is unchanged with varying cylinder pressure
an in depth understanding of all the special rules recommendations and considerations can help you
avoid decompression sickness
___________________ is "stomach breathing" used before breath-hold dives in which the lower abdomen expands when you inhale. a) Hyperventilation b) Diaphragmatic breathing c) Square breathing d) Skip breathing
b) Diaphragmatic breathing
Why does a diver become light-headed with a dry suit neck seal that is too tight a) It reduces the exit of oxygen-poor blood from the brain and lowers blood pressure in the head, raising the heart rate. b) It reduces fresh blood flow to the brain, raises blood pressure in the head and slows the heart rate c) It squeezes the nerves in the neck and increases blood flow to the brain, slowing the heart rate d) It squeezes the trachea and throat, which raises blood pressure and raises the heart rate.
b) It reduces fresh blood flow to the brain, raises blood pressure in the head and slows the heart rate
The lung expansion injury characterized by air accumulation over the heart is: a) Pneumothorax b) Mediastinal emphysema c) Subcutaneous emphysema d) Arterial Gas Embolism
b) Mediastinal emphysema
Typically, AGE affects ______of the body and the symptoms appear ___, / whereas DCS typically affects _____ of the body and the symptoms appear ______. a) Both sides, immediately / one side, after a few hours b) One side, immediately / both sides, after a few hours c) Both sides, after a few hours / one side, immediately d) One side, after a few hours / both sides, immediately
b) One side, immediately / both sides, after a few hours
Mediastinal emphysema results when air for a lung over expansion injury: a) accumulates at the base of the neck b) accumulates over the center of the chest and presses the heart c) collapses a lung d) enters the bloodstream
b) accumulates over the center of the chest and presses the heart Air from a ruptured lung can form in the centre of the chest on the top of the heart pressing against it. This can result in symptoms like fainting, shortness of breath due to the pressure on the heart.
Gas exchange between the respiratory and circulatory system occurs: a) in the carotid arteries b) between the pulmonary capillaries and the alveoli c) between the bronchi and the pulmonary arteries d) None of the above
b) between the pulmonary capillaries and the alveoli Remember that gas exchange between the respiratory system and the circulatory system occurs in the alveoli, but gas exchange between the tissues and the blood occurs in the capillaries.
Smoking, _________________ and breath holding during ascent, may contribute to the risk of a lung over expansion injury. a) alcohol b) chest congestion c) dehydration d) exercise before the dive
b) chest congestion
An increase in the partial pressure of nitrogen could result in a) oxygen toxicity b) gas narcosis c) rupture of red blood cells d) lung over expansion injuries
b) gas narcosis
The worst situation for a diver near the end of a dive would be: a) having middle ear squeeze b) having a reverse block c) having a suit squeeze d) There is no difference
b) having a reverse block
You've just climbed back into the boat after a deep dive and vertical ascent, and your buddy complains of dizziness, shortness of breath, and pains down one side of his body. These could be symptoms of _________________ and the best course of action would be a) decompression sickness; provide fluids b) lung-over expansion injury; provide oxygen c) carotid sinus reflex; loosen his wet suit or remove his hood d) overexertion; have him relax until his breathing calms
b) lung-over expansion injury; provide oxygen
Due to gas density, the deeper you're diving the more easily you can: a) breathe b) overexert yourself c) reduce carbon dioxide levels d) move
b) overexert yourself
Heat exhaustion signs and symptoms include: a) strong rapid pulse, no perspiration, skin hot to touch b) weak, rapid breathing, weak rapid pulse, profuse sweating, skin cool and clammy, nausea c) no shivering, drowsiness, lack of coordination, coma d) shivering, numbness in fingers and toes
b) weak, rapid breathing, weak rapid pulse, profuse sweating, skin cool and clammy, nausea
Assume that the atmosphere contains 80% nitrogen. At sea level, the nitrogen partial pressure within our tissues would be: 1.0 ata 0.8 ata 0.2 ata The answer cannot be determined from the data provided. Submit
b. .8 ata Our tissues are primarily liquid. Therefore, if the gas in contact with our tissues is comprised of 80% nitrogen, then our tissues will contain a gas tension of 80% nitrogen. 80% of 1 ata is .8 ata (.80 x 1 = .8).
The specific gravity of pure water is: a. 0.0 b. 1.0 c. It varies according to where on earth it is measured. d. It cannot be determined except in a vacuum.
b. 1.0 The specific gravity of pure water is 1.0. Pure water is used as the basis of the specific gravity scale. Therefore, it is assigned the value of 1.0. Substances with a value less than 1.0 are, by definition, less dense than pure water and will float. Substances with values greater than 1.0 are more dense and will sink.
What would the volume of the balloon in question 1 be if it is taken to 165 feet of seawater? a. 2 cubic feet b. 1.67 cubic feet c. 9.5 cubic feet
b. 1.67 The volume of the balloon in question 1 would be 1.67 cubic feet if it is taken to 165 feet of seawater. Remember this simple rule: always bring the object to the surface, then return to the depth in question. Step 1. Determine what pressure is exerted by 165 feet of depth. By dividing 33 feet (which is one atmosphere of pressure) into 165 feet we find that the pressure is 5 atm gauge. We must then add the 1 atm from the surface to arrive at 6 atm absolute. So, the question really asks, what will the volume be as the balloon reaches 6 ata? But first, let's take the balloon to the surface. From question 1, we determined that the balloon would contain 10 cubic feet at the surface. Let's now apply a simple relationship — the quantity in question over the number of atmospheres. In this case the quantity of 10 cubic feet over 6 ata or 10/6. All that is left is to reduce the fraction or divide — 1.67 cubic feet.
An object weighing 750 pounds and displacing 10 cubic feet is lying in 50 feet of fresh water. If a drum is to be used to lift the object to the surface, how much water must be displaced from the drum? a. 1.72 cubic feet b. 2 cubic feet c. For any inflexible drum to be used, it must always be completely filled. d. The answer cannot be determined from the data provided.
b. 2 cubic ft. 62.4 x 10 = 624 750-624 = 126 126÷62.4 = 2.019 An object weighing 750 pounds and displacing 10 cubic feet is lying in 50 feet of fresh water. If a drum is to be used to lift the object to the surface, 2 cubic feet of water must be displaced from the drum. The object weighs 750 pounds. As in the previous problem, the object also displaces 10 cubic feet. Each cubic foot of displacement represents 62.4 pounds/cubic feet of upward buoyant force. (We are now in fresh water — 1 cubic foot of fresh water weighs 62.4 pounds). Therefore, the total buoyant force is 624 pounds (62.4 x 10 = 624). In essence, we have an upward buoyant force of 624 pounds counteracting the downward gravitational force of 750 pounds. The object sank because there was 126 pounds more downward than upward force (750 - 624 = 126). To equalize the forces, making the object neutrally buoyant, we must now add 126 pounds of buoyancy to the object. Displacing 2 cubic feet of water from a lifting device will provide sufficient additional buoyancy (126 ÷ 62.4 = 2). Again, because water is for all practical purposes incompressible, the depth of the water can be ignored.
Carbon monoxide bonds with hemoglobin over _____ times faster than oxygen can and it may take _______ for the circulatory system to eliminate it a. 20 / 8 to 10 hours b. 200 / 8 to 12 hours c. 300 / 8 to 12 hours d. 200 / 6 to 9 hours
b. 200 / 8 to 12 hours
A glass of water has been placed in a vacuum for several days. It no longer contains any dissolved gas within it. If it is then placed in a pressure pot and pressurized to 2 ata for several days, what will be the gas pressure within the liquid? 1 ata 2 ata 4 ata The answer is impossible to determine.
b. 2ata There is a tendency for a state of equilibrium to exist between the pressure within a liquid (gas tension), and the pressure of the gas in contact with that liquid. This equilibrium will be maintained until the pressure in contact with the liquid changes. This phenomenon was first explained by chemist William Henry. Through experimentation Henry concluded — as Henry's Law states — that, "the amount of gas that will dissolve into a liquid is almost directly proportional to the partial pressure of that gas."
When viewed underwater, objects tend to be magnified by a factor of about: a. 10% b. 33% c. 50% d. 74%
b. 33% When viewed underwater, objects tend to be magnified by a factor of about 33%. Light passing through the water/air interface refracts (bends). The effect is similar to an object being viewed under a magnifying glass. If no other factors come into play, objects will appear larger by about 33%.
A gas mixture is comprised of 21% oxygen, 78% nitrogen and 1% carbon dioxide. At a depth of 66 feet of seawater, what is the partial pressure of the nitrogen? a. 22.93 psia b. 34.39 psia c. 78.00 psia d. The answer cannot be determined from the data provided.
b. 34.39psia Similar to the previous question, we must first determine the absolute pressure. At 66 feet this is 44.1 psia (14.7 x 3 = 44.1). Next, determine the percentage of the gas in question. In this case, nitrogen comprises 78% of the total. So, 44.1 x .78 = 34.39 psia.
Approximately how much water must be displaced to bring a 900 pound object to the surface if the object displaced 10 cubic feet? The object lies in 132 feet of seawater. a. Slightly more than 8 cubic feet b. Slightly more than 4 cubic feet. c. Slightly more than 1 cubic foot. d. The answer cannot be determined from the data provided.
b. 4.0625 64 x 10=640 water displaced 900lb object-640=260. 260 / 64 = 4.0625 Slightly more than 4 cubic feet must be displaced to bring a 900 pound object to the surface if the object displaced 10 cubic feet and lies in 132 feet of seawater. The object weighs 900 pounds. This represents a downward gravitational force. The object also displaces 10 cubic feet of water. Each cubic foot of displacement represents 64 pounds/cubic foot of upward buoyant force. (Remember, we are in seawater). Therefore, the total buoyant force is 640 pounds (64 x 10 = 640). We in essence have an upward buoyant force of 640 pounds counteracting the downward gravitational force of 900 pounds. The object, in fact, sank because there was 260 pounds more downward force than upward (900 - 640 = 260). To equalize the forces, making the object neutrally buoyant, we must somehow add 260 pounds of buoyancy to the object. If a lift bag is attached, each cubic foot of air added to it will provide an additional 64 pounds of buoyancy. Therefore, we can acquire the additional buoyancy by displacing a little more than 4 cubic feet of water (260 ÷ 64 = 4.06). Incidentally, because water is for all practical purposes incompressible, the depth of the water can be ignored.
The ambient pressure 100 feet of seawater is: a. 44.5 psia b. 59.2 psia c. 73.9 psia d. The answer cannot be determined from the data provided.
b. 59.2 The ambient pressure at 100 feet of seawater is: 59.2 psia. Ambient means nothing more than "surrounding" pressure. Therefore, the ambient pressure is synonymous with absolute pressure. We can then proceed in the same manner as in the previous problem. To find out how much pressure the water (remember it's seawater) exerts, multiply .445 psi/ft times 100 feet. The water pressure alone is 44.5 psig. But we must account for the atmospheric pressure. Therefore, we must add 14.7 psi to the 44.5 psig to determine the ambient or absolute pressure of 59.2 psia.
The air that a diver breathes from a scuba cylinder at 165 feet of seawater is ______ as dense as the air breathed from the same cylinder at the surface. a. 10 times b. 6 times c. 5 times d. exactly
b. 6 times The air that a diver breathes from a scuba cylinder at 165 feet of seawater is 6 times as dense as the air breathed from the same cylinder at the surface. This relates to the previous question. In order to breathe underwater, the air must be at the same pressure as the surrounding water pressure. In this instance, the diver is in 165 feet. The depth exerts 5 atm gauge pressure (165 ÷ 33 = 5). Add 1 additional atm for the surface pressure and we get 6 ata. At 6 ata the pressure is six times greater than at the surface. Therefore, the air the diver breathes must be 6 times more dense in order to fully inflate his lungs at that depth.
A diver has an air consumption rate of 3 cubic feet per minute at 66 feet of seawater. If all factors, but depth remain unchanged, what will his consumption rate be at 200 feet? a. 6 cubic feet per minute b. 7 cubic feet per minute c. 8 cubic feet per minute d. The answer cannot be determined from the data provided.
b. 7 Similar to the previous question, we must first determine the surface consumption rate. In this case, the diver will consume one third the amount of air at the surface as at 66 feet (3 ata), or 1 cubic foot per minute. Next, we must determine what pressure 200 feet of water exerts in terms of whole atmospheres. By dividing 33 feet into 200 feet, we determine that 200 feet is 6 atm gauge, 7 atm absolute. As we must always work in absolute terms, we now know that his air consumption rate will increase to slightly more than seven fold at 200 feet. Note: while this theoretical example assumes a dive to 200 feet, the maximum depth for actual recreational dives is never to exceed 130 feet.
Filling scuba tanks with pure oxygen is not advised because: a. The body needs to obtain nitrogen from breathing air b. Breathing pure oxygen under pressure can be toxic, even at shallow depth c. This is used for only a specialized type of deep-diving d. The tank will not hold as much when filled only with oxygen
b. Breathing pure oxygen under pressure can be toxic, even at shallow depth
Light waves contain _______, while sound waves are comprised of _______. a. heat energy/air b. electromagnetic energy/mechanical energy c. infrared energy/ultraviolet energy d. kinetic energy/potential energy
b. Light waves contain electromagnetic energy, while sound waves are compromised of mechanical energy. Light waves contain electromagnetic energy, while sound waves are comprised of mechanical energy. Light is a form of electromagnetic energy that is visible to us. Most forms of electromagnetic energy - cosmic rays, X-rays, radio waves - are not. Sound results when an object sets in motion a series of vibrations. These vibrations, in turn, create mechanical energy (sound waves) that are transmitted and perceived by us as sound.
Water is able to conduct heat far more efficiently than air because it is: a. less dense than air. b. more dense than air. c. more fluid than air. d. less fluid than air.
b. More Dense than Air. Water is able to conduct heat far more efficiently than air because it is more dense than air. Water conducts heat more effectively than air because the molecules are closer together. This makes it easier for the heat (energy) to be transferred or conducted. In addition, the "polar" nature of the water molecule, resulting from the hydrogen bonds, enables water to absorb more heat than other liquids.
Decompression sickness results where the pressure gradient (change) between the ambient pressure and the pressure within the bodies' tissue exceeds acceptable limits. a. False b. True
b. True
True or False: Silent bubbles are microscopic, asymptomatic bubbles that may be detected with a Doppler ultrasound flow meter. a. False b. True
b. True
The single most important factor affecting the "visual reversal" phenomenon is: a. Depth b. Turbidity c. Time of day
b. Turbidity The single most important factor affecting the "visual reversal" phenomenon is turbidity. Studies have shown several factors affecting the phenomenon. However, the turbidity of the water appears to be one of the major factors.
A balloon is filled with 1 cubic foot of air at room temperature. Describe what would happen to that balloon if it were put into a freezer at a constant ambient pressure. a. The volume would increase. b. The volume would decrease. c. The volume would remain unchanged but the pressure would decrease. d. The volume and the pressure would remain unchanged.
b. decrease When placed in a freezer, the energy contained in the gas molecules within the room temperature tank will begin to dissipate. As the temperature decreases, the motion of the molecules decreases. As the motion decreases, the force of impact of their collisions with each other and the sides of the balloon decreases. Less force of impact means less pressure inside the balloon, and it would therefore shrink, or decrease in volume. This is a description of Charles' Law which states, "the amount of change in volume of gas is directly proportional to the change in the absolute temperature at a constant pressure."
If a vacuum is created within the pressure pot in question 1 (A glass of water has been placed in a vacuum for several days. It no longer contains any dissolved gas within it. it is then placed in a pressure pot and pressurized to 2 ata for several days), the pressure of the gas within the liquid will: increase. decrease. remain unchanged. The answer cannot be determined from the data provided. Submit
b. decrease This question is simply the reverse of the previous. A vacuum would represent zero pressure in contact with the liquid. Therefore, the tendency would be for any gas contained in the liquid to come out. So, the pressure would decrease.
According to Archimedes' Principle, "Any object wholly or partially immersed in a fluid is buoyed up by a force ___________." a. equal to the weight of the object b. equal to the weight of the fluid displaced by the object c. equal to the weight of both the object and the weight of the fluid displaced by the object d. slightly less than the weight of the object
b. equal to the weight of the fluid displaced by the object. According to Archimedes' Principle, "Any object wholly or partially immersed in a fluid is buoyed up by a force equal to the weight of the fluid displaced by the object." This is why it's important to know the displacement of an object. By knowing its displacement, and using a constant "density," you can easily find out the buoyant force on any object immersed in fresh or salt water.
Sound travels approximately ____ times faster in water than it does in air. a. two b. four c. ten d. twenty
b. four Sound travels approximately 4 times faster in water than it does in air. In air sound travels approximately 1100 feet per second. In water it travels 4800 feet per second.
Referring to question 2, because our tissues cannot hold any more gas pressure at sea level, our body is referred to as being: pressurized. saturated. supersaturated. unsaturated.
b. saturated Saturation refers to the fact than there is no net exchange of gases between the tissues (liquid) and the gas in contact with them. This is the state of equilibrium.
pharynx
back of the throat, is connected to the nasal and oral cavities. It primarily humidifies and warms the air entering the respiratory system.
The primary advantage of a __________________ over an unbalanced one is that they breathe easier at greater depths, even at low tank pressures, provide greater air flow, and are better able to supply a second diver breathing from an octopus. A closed circuit B balanced first stage C first stage valve D downstream valve
balanced first stage
Boyle
balloon - pressure and volume
RDP bottom time definition
beginning of descent to beginning of ascent (SS not included)
heat stroke
bodies cooling mechanisms have failed, no perspiration, skin hot and flushed, can result in unconsciousness and death.
The advantage of the _______________ search pattern is that you can conduct it without special equipment. Choose your answer. A expanding square B U-shaped C circular D both a and b
both a and b
An analog SPG uses a _____________ to detect cylinder pressure
bourdon tube
a capillary depth gauge works by using
boyles law
Filling scuba tanks with pure oxygen is not advised because: A the body needs to obtain nitrogen from breathing air. B breathing pure oxygen under pressure can be toxic, even at shallow depths. C this is used only for a specialized type of deep diving. D the tank will not hold as much when filled only with oxygen.
breathing pure oxygen under pressure can be toxic, even at shallow depths.
Filling scuba tanks with pure oxygen is not advised because: Choose your answer. A the body needs to obtain nitrogen from breathing air. B breathing pure oxygen under pressure can be toxic, even at shallow depths. C this is used only for a specialized type of deep diving. D the tank will not hold as much when filled only with oxygen.
breathing pure oxygen under pressure can be toxic, even at shallow depths.
Surfactant is a substance that coats the inner surfaces of the ______________ and helps prevent them from____________________.
bronchioles and alveoli / collapsing
Why does DCS occur to recreational divers upon resurfacing rather than while they are at depth?
bubble formation can occur until the tissues become supersaturated. IE hold more gas than the ambient pressure. this can only occur on ascent.
why does DCS occur to recreational divers upon resurfacing rather than while they are at depth?
bubble formation can occur until the tissues become supersaturated. IE hold more gas than the ambient pressure. this can only occur on ascent.
What device prevents an over pressurized cylinder from exploding
burst disk
eustachian tube, middle ear
by equalizing your ears you force air through the ...... into the.....
After a dive a diver displays the signs and symptoms of tunnel vision and cherry red nail beds. The most likely cause is: a) DCS b) Lung over expansion c) Contaminated air poisoning d) All the above
c) Contaminated air poisoning
Shallow water blackout is caused by: a) Increased levels of carbon monoxide b) Increased levels of nitrogen c) Decreased partial pressure of oxygen d) Fast ascents
c) Decreased partial pressure of oxygen
Excessive voluntary hyperventilation can cause ____________ while involuntary hyperventilation can cause ________________? a) Hypoxia, Hypercapnia b) Hypercapnia, Hypocapnia c) Hypocapnia, Hypercapnia d) Hyperoxia, Hypoxia
c) Hypocapnia, Hypercapnia
The greatest risk of a forceful Valsalva maneuver is: a) Eardrum rupture b) Sinus rupture c) Round window rupture d) Oval window rupture
c) Round window rupture
The body responds to apnea in cold water with: a) hyperventilation b) tachycardia c) bradycardia d) hyperoxia
c) bradycardia The bradycardia response to apnea has sometimes been called the mammalian diving reflex/mammalian reflex. This reflex is associated with cold water on the face. It can be said that the mammalian reflex is bradycardia response to apnea, or that the body responds to apnea in cool water with bradycardia.
A diver who complains of fatigue, a red rash, tingling, and numbness in one shoulder hours after surfacing from a two dive series, should seek medical attention because he most likely is suffering from: a) contaminated air poisoning b) an allergy to marine life c) decompression illness d) carrying equipment that is too heavy
c) decompression illness Bubbles under skin, Joint pain, Tingling, Numbness, Extreme fatigue, Unconsciousness
A squeeze is caused by: a) inert gas affecting the nervous system b) vasoconstriction in the fingers and toes c) failure to equalize a body air space d) the formation of silent bubbles
c) failure to equalize a body air space Barotrauma is a pressure related injury which results from a squeeze and is cause by the failure to equalize and air space. Any air space can suffer from a barotraumas. Descending barotraumas are called squeezes and ascending barotraumas are called reverse squeezes, reverse blocks or expansion injuries.
Cases in drowning in very cold water can make revival a) impossible b) quite unlikely c) possible even after fairly long periods of time d) possible, but only if the patient has not been immersed long
c) possible even after fairly long periods of time
The symptoms of decompression sickness tend to appear __________while the symptoms of lung over expansion injuries tend to appear ___________________ a) immediately after the dive; more slowly b) slowly over several days; immediately after surfacing c) within the first few hours; within minutes after the dive d) only after surfacing; usually at depth
c) within the first few hours; within minutes after the dive
The absolute pressure at a depth of 300 feet of seawater is: a. 118.8 psia b. 133.5 psia c. 148.2 psia d. The answer cannot be determined from the data provided.
c. 148.2 Seawater = .445psi/ft 300 x .445 = 133.5 133.5 + 1 atmosphere (14.7) = 148.2 Absolute pressure is the sum of both the pressure exerted by the water column and the atmosphere. Therefore, to find out how much pressure the water (remember, it's seawater) exerts, multiply .445 psi/ft times 300 feet. The water pressure alone is 133.5 psig (.445 x 300 = 133.5). But, as the atmosphere exerts pressure on the water, and this pressure is evenly distributed throughout the water column, we must also account for it. Therefore, we must add 14.7 psi to the 133.5 psig to determine the total or absolute pressure of 148.2 psia.
Breathing from a contaminated air source, with 1.5% carbon monoxide, at a depth of 300 feet of seawater, would have the same effect as breathing approximately what percentage of carbon monoxide at the surface? 1.5% 13.5% 15% The answer cannot be determined from the data provided.
c. 15% This question is just a slightly more complicated version of the previous. First, we saw from questions involving previous objectives that 300 feet is close enough to be considered 10 atm. Then, if we are breathing a gas of a certain percentage, it will have 10 times the effect on us at 10 ata. In this case, the percentage of contamination is 1.5%. So, it would have the same effect at 300 feet as breathing 15% at the surface. (1.5 x 10 = 15).
A balloon containing 1 cubic foot of air is released from 10 ata. If it does not explode, how much air will be in the balloon upon reaching the surface? a. 30 cubic feet b. 20 cubic feet c. 10 cubic feet d. The answer cannot be determined from the data provided.
c. A balloon containing 1 cubic foot of air is released from 10 ata. If it does not explode, 10 cubic feet of air will be in the balloon upon reaching the surface. A simple relationship holds true when dealing with increments of whole atmospheres. Specifically, a flexible container will expand upon ascent, and reach the surface with the original quantity of gas times the number of atmospheres from which it was released. In this case, as the container started with 1 cubic foot at 10 ata, the gas will expand 10 times by the time it reaches the surface. This problem deals with Boyle's Law which states, "if the temperature remains constant, the volume of a given mass of gas is inversely proportional to the absolute pressure."
At a depth of 112 feet in fresh water the absolute pressure is __________, the gauge pressure is __________ and the ambient pressure is __________. a. 64.54 psia/49.84 psig/64.54 psia b. 48.38 psia/33.68 psig/48.38 psia c. 63.08 psia/48.38 psig/63.08 psia d. 63.08 psia/48.38 psig/48.38 psia
c. At a depth of 112 feet in fresh water the absolute pressure is 63.08 psia, the gauge pressure is 48.38 psig and the ambient pressure is 63.08 psia. To determine the absolute pressure at 112 feet, multiply the freshwater constant .432 psi/ft with the depth. This tells us that the water pressure alone accounts for 48.38 psig. Since this ignores the atmospheric pressure, this represents the gauge pressure at 112 feet. To obtain the absolute pressure merely add 14.7 psi. As absolute and ambient are synonymous terms, both pressures are 63.08 psia.
When viewed underwater, objects normally appear _______ by a ratio of about _____ (actual to apparent distance). a. closer/2:1 b. further away/4:3 c. closer/4:3 d. further away/2:1
c. Closer /4:3 When viewed underwater, objects normally appear closer by a ratio of about 4:3 (actual to apparent distance). Light passing through the water/air interface refracts (bends). The effect is similar to an object being viewed under a magnifying glass. If no other factors come into play, objects will appear closer by a ratio of about 4:3.
The lung over expansion injury characterized by air accumulation over the heart is: a. Arterial Gas Embolism b. Subcutaneous emphysema c. Mediastinal emphysema d. Pneumothorax
c. Mediastinal emphysema
CNS oxygen toxicity has symptoms that include: a. Irritated cough and tightness in the chest b. Cherry red lips and fingernail beds c. Nausea, twitching and ear ringing d. All of the above
c. Nausea, twitching and ear ringing
A scuba cylinder is filled to capacity at room temperature. Describe what would happen to that cylinder if it was taken on an ice dive (water at or near freezing). a. The volume would increase. b. The volume would decrease. c. The volume would remain unchanged but the pressure would decrease. d. The volume and the pressure would remain unchanged.
c. the volume would remain unchanged but the pressure would decrease.
Large amounts of carbon dioxide can be carried by the circulatory system back to the lungs for expiration primarily because carbon dioxide:
can be converted into bicarbonate.
no
can you taste or smell carbon monoxide?
Overexertion that occurs as a result of physical activity or shallow, inefficient breathing, causes a buildup of _________ in the body. A carbon monoxide B carbon dioxide C nitrogen D insulin
carbon dioxide
Overexertion that occurs as a result of physical activity or shallow, inefficient breathing, causes a buildup of _________ in the body. Choose your answer. A carbon monoxide B carbon dioxide C nitrogen D insulin
carbon dioxide
the reflux respiratory center regulates breathing based primarily on the level of____________in the blood.
carbon dioxide
The carotid-sinus receptors, which are located in the carotid arteries, stimulate the_______________, which is located in the_______________.
cardioinhibitory center / brain
arteries
carry blood away from heart
veins
carry blood to the heart / oxygen poor blood
Rebreathers can use a
closed circuit and a semi closed circuit they recycle usable exhaled gases and remove CO2
CCR
closed-circuit rebreather, a form of scuba that is more efficient because it recycles exhaled gases instead of releasing them as bubbles
inner ear
cochlea
Which of the five steps of planning a search and recovery dive involves determining an object's size and weight? Choose your answer. A defining the objectives B collecting and analyzing information C selecting a buddy or team D briefing
collecting and analyzing information
Molecular elements
compounds that consist entirely of atoms from a single element
The _____________________ for administering one-rescuer CPR is 30/2. Choose your answer. A landmark check B compression-to-ventilation ratio C rescue breath D None of the above.
compression-to-ventilation ratio
___________, a form of heat transmission, has the greatest affect on heat loss in a diver while ________ is the form that has the least affect. Choose your answer. A convection/radiation B radiation/conduction C conduction/radiation D conduction/convection
conduction/radiation
Factors that influence a diver's susceptibility to decompression sickness include: Choose your answer. A consuming alcohol before or after a dive. B heavy exercise. C obesity. D All of the above are correct.
consuming alcohol before or after a dive heavy exercise obesity D All of the above are correct.
oxygen toxicity
convulsions caused by oxygen at depth; safe limits determined by the proportion of oxygen in the gas and the depth
To prevent a scuba cylinder from rupturing due to overpressurization, a burst disk may be installed in the ______________ , and is designed to rupture when the cylinder pressure rises above about 140 percent of the cylinder's rated pressure.
cylinder valve - If cylinder pressure rises to approximately 140 percent of the working pressure, the burst disk in the cylinder valve ruptures, and the air escapes through the vented plug.
You would administer emergency oxygen (preferably 100%) for: a) suspected Type 1 DCS b) suspected Type 2 DCS c) suspected AGE d) All of the above
d) All of the above Both DCS and lung over-expansion injuries (discussed later) require the same first aid, there's no need to distinguish between them when providing care.
Barotrauma is a term used to describe: a) Lung expansion Injuries b) Mask Squeeze c) Eardrum Rupture d) All the above
d) All the above
Factors that may increase a diver's risk of lung overexpansion injuries include: a) Smoking b) Choking on a dislodged mouthpiece c) Breath-holding d) All the above
d) All the above
Which factors may predispose a diver to DCS? a) Obesity (excessive fat) b) Dehydration c) Alcohol consumption d) All the above
d) All the above
Which is/are the physiological response(s) to cold? a) Shivering b) Vasoconstriction c) Confusion d) All the above
d) All the above
Which of the following is a sign of heat stroke? a) cool, dry skin b) Shivering c) Cool, clammy skin d) Hot, flushed (red), dry skin
d) Hot, flushed (red), dry skin
The best way to avoid pulmonary oxygen toxicity is to: a) Never exceed an O² partial pressure of 1.4ata b) Use Trimix or Heliox whenever possible when diving c) Obtain air fills from a reputable vendor d) Never exceed 100% of the daily O² exposure on your dive computer
d) Never exceed 100% of the daily O² exposure on your dive computer
Extremely advanced hypothermia: a) has symptoms including shivering and numb fingers and toes b) is easily handled by simple rewarming c) is impossible when wearing an exposure suit d) None of the above
d) None of the above one of the first symptoms of serious hypothermia is diminished awareness
The most serious lung over expansion injury is a(n)__________________. The first aid procedures __________________________. a) mediastinal emphysema; remain the same for all b) pneumothorax; are different for each c) subcutaneous emphysema; are different for each d) air embolism; remain the same for all
d) air embolism; remain the same for all
The danger of a diver breathing pure oxygen underwater is that a) the body needs nitrogen, even at shallow depths b) it can increase the risk of decompression sickness c) it can increase the risk of carbon monoxide poisoning d) breathing pure oxygen under pressure can be toxic, even at shallow depths
d) breathing pure oxygen under pressure can be toxic, even at shallow depths
After surfacing from a short dive, both buddies complain headaches, nausea, narrowed vision, and dizziness. You may suspect they are suffering from: a) decompression sickness b) nitrogen narcosis c) hypothermia d) carbon monoxide poisoning
d) carbon monoxide poisoning
You surface from a dive to find another diver sitting on the deck of the boat, having just completed a deep dive. In speaking with him, you learn that he had been to a party the night before and had consumed alcohol. He is complaining of numbness and tingling in his legs, and extreme fatigue. These are signs and symptoms of a) carbon monoxide poisoning b) a hangover c) oxygen toxicity d) decompression sickness
d) decompression sickness
An air embolism results when air from a lung overexpansion injury: a) accumulates at the base of the neck b) accumulates over the center of the chest and presses in the heart c) collapses a lung d) enters the bloodstream
d) enters the bloodstream This is the most serious form of lung over expansion injuries. It occurs when the alveoli and pulmonary capillaries rupture, allowing air to enter the bloodstream. This results into Arterial blockage as air bubbles block anywhere in your bloodstream. Once those bubbles travel up your the carotid arteries they cause Cerebral Air embolism and result in dizziness, unconsciousness, paralysis and death.
Carbon monoxide is hazardous because: a) it causes hypercapnia b) it leads t heavy breathing at depth and overexertion c) it alters the release of dissolved nitrogen d) it bonds with hemoglobin, interfering with oxygen transport
d) it bonds with hemoglobin, interfering with oxygen transport Carbon monoxide bonds with the hemoglobin over 200 times more readily than oxygen is able to, though does not unbind so easily. It can take the circulatory system 8-12 hours to eliminate it.
If a diver complains of difficulty breathing, tingling, and numbness almost immediately after a dive they most probably have? a) decompression sickness b) seasickness c) vertigo d) lung over expansion injury
d) lung over expansion injury
"Visual reversal" refers to an object's tendency to appear: a. as a mirror image of itself. b. upside down, as though viewed through a magnifying lens. c. like a photographic negative. d. further away than its actual distance.
d. "Visual reversal" refers to an object's tendency to appear further away than its actual distance. The visual reversal phenomenon is more a function of human perception than of physics. In essence, the lack of contrast and other familiar visual references we are used to seeing on the surface are not present underwater. As a result, we can be tricked into perceiving objects as further away than their actual distance from us.
A diver has an air consumption rate of 25 psig per minute at the surface. If all other factors but depth remain unchanged, what will his consumption rate be at 132 feet of seawater? a. 50 psig/minute b. 75 psig/minute c. 100 psig/minute d. 125 psig/minute
d. 125 25 x 5 ata = 125
Referring to the previous question (a scuba cylinder is accidentally filled with 1% carbon monoxide), it is determined that at the surface the diver inhales 500,000 molecules of carbon monoxide with each breath. Therefore, when breathing the air at 100 feet of seawater (assuming all other factors but depth are unchanged), he would breathe approximately how many molecules? 500,000 1,000,000 1,500,000 2,000,000
d. 2,000,000 Remember that in order to breathe underwater (under increased pressure), the air that is breathed must be at the same pressure as the surrounding water. This makes the air more dense. As a result, the diver will inhale more molecules. In this problem the diver is breathing air at 100 feet, which is approximately 4 ata. Therefore, the air he is breathing must be four times more dense than at the surface. He must then inhale four times the number of molecules. So, if he inhales 500,000 in each breath at the surface, he must inhale 2,000,000 at a depth of 100 feet. Note that while significantly more molecules reach the diver's lungs at depth, the actual percentage of the gas in the cylinder is still unchanged.
Water is able to conduct heat about ______ times faster than air. a. 3200 b. 775 c. 100 d. 20
d. 20 times faster than air. Water is able to conduct heat about 20 times faster than air. This is why submerged divers become chilled very quickly in water - even in water at a temperature that might be considered comfortable in air.
A diver has an air consumption rate of 2 cubic feet per minute at 33 feet of seawater. If all other factors but depth remain unchanged, what will his consumption rate be at 99 feet? a. 0.5 cubic foot per minute b. 1 cubic foot per minute c. 3 cubic feet per minute d. 4 cubic feet per minute
d. 4 As in previous problems involving pressure and volume, the key here is to first determine the rate at the surface. In this case, a diver who consumes 2 cubic feet of air per minute at 33 feet (2 ata), will consume half that amount — 1 cubic foot — at the surface. (Remember, air consumption is a function of density; it decreases as pressure is reduced).Therefore, if all factors are equal, at 99 feet (4 ata) he will consume 4 times the amount of air. Four times the surface amount (1 cubic foot) is 4 cubic feet.
Again referring to question 1 (a scuba cylinder is accidentally filled with 1% carbon monoxide), breathing the contaminated air at 100 feet of seawater would have the same effect on the diver as breathing what percentage of carbon monoxide at the surface? 1% 2% 3% 4% Submit
d. 4% In order to understand this question more clearly, ask yourself, "what percentage of gas would the diver have to breathe at the surface in order to get the 2,000,000 molecules of carbon monoxide?" 2,000,000 molecules is four times the amount of gas he was breathing at the surface, and the mixture contains only 1% carbon monoxide. Therefore, he would require 4 times the amount of carbon monoxide at the surface — 4% — in order to get the same effect as breathing only 1% at 100 feet. That's why this phenomenon is referred to as "surface equivalency." By the way, a gas mixture of 4% carbon monoxide at the surface would be extremely poisonous.
Air bubbles entering arteries and blocking blood flow shows that a diver is suffering from which lung expansion injury? a. Pneumothorax b. Mediastinal Emphysema c. Subcutaneous Emphysema d. Air Embolism
d. Air Embolism
Excessive hyperventilation before a breath hold dive may lead to: a. Shallow water blackout b. Hypoxia c. Hypocapnia d. All of the above
d. All of the above
Breathing from a poorly adjusted regulator or swimming against a strong current may cause _____. a. Rapid, shallow or labored breathing b. Hypercapnia or excessive carbon dioxide c. Overexertion d. All of the above are correct
d. All of the above are correct
Approximately how much air must be added to a lifting device to bring a 1200 pound object to the surface? The object lies in 100 feet of fresh water. a. 19 cubic feet b. 18 cubic feet c. 16 cubic feet d. The answer cannot be determined from the data provided.
d. It cannot be determined how much air must be added to a lifting device to bring a 1200 pound object lying in 100 feet fresh water to the surface. Buoyancy is a function of both the weight of an object and its displacement. Unless the displacement is known, you cannot calculate the amount of buoyant force on an object.
If a diver wears a suit with an excessively tight hood or next seal, he may risk unconsciousness due to _____. This is called _________. a. Excessive carbon dioxide levels / shallow water blackout b. Low carbon dioxide levels / hypocapnia c. Low oxygen levels / hypoxemia d. Reduced blood flow to the brain / carotid sinus reflex
d. Reduced blood flow to the brain / carotid sinus reflex
A diver who complains of extreme fatigue and arm numbness several hours after a deep dive may be suffering from: Choose your answer. A nitrogen narcosis. B contaminated air poisoning. C decompression illness. D pneumothorax.
decompression illness
A diver who complains of extreme fatigue and arm numbness several hours after a deep dive may be suffering from: A nitrogen narcosis. B contaminated air poisoning. C decompression illness. D pneumothorax.
decompression illness.
You should not turn off your dive computer, or replace the batteries between dives, because that would cause it to lose any memory of previous dives, which could cause it to calculate repetitive dives incorrectly and create an unacceptable risk of _________________. A decompression sickness B air embolism C headache D nitrogen narcosis
decompression sickness
In recreational diving a ______________ ______________ is considered and emergency procedure only and never part of the dive plan
decompression stop
If the ambient air pressure surrounding a liquid filled open container is quickly decreased, the amount of gas that is dissolved in the liquid will ____________. Choose your answer. A decrease and gas bubbles may form. B remain unchanged. C increase until reaching a state of equilibrium. D decrease, but only if the gas is nitrogen.
decrease and gas bubbles may form.
when a breath-holding divers emerges into cold water his heart rate will:
decrease.
You should avoid cigarette smoking prior to a dive because it ______ the body's ability to transport oxygen due to an increased ______ level in the lungs. A increases/nitrogen B decreases/carbon monoxide C increases/carbon dioxide D decreases/nicotine
decreases/carbon monoxide
You should avoid cigarette smoking prior to a dive because it ______ the body's ability to transport oxygen due to an increased ______ level in the lungs. Choose your answer. A increases/nitrogen B decreases/carbon monoxide C increases/carbon dioxide D decreases/nicotine
decreases/carbon monoxide
which of the following are recommendations or rules for RDP use
deeper dives before shallow dives safety stops at the end of all dives plan cold/strenuous dives 10 feet deeper than actual depth 12 hours before flying
Bar gauge pressure
depth / weight of water (sea or fresh) = bar pressure * add 1 bar for ambient pressure
In terms of equipment considerations, avoiding the maximum limits of the dive tables is wise because
depth gauges can malfunction or be read inaccurately
why perform a visual inspection on a cylinder
detect exterior damage (severe scratches/dents) severe interior corrosion particularly in steel cylinders prevent galvanic action between dissimilar metals of the cylinder and valve threads
identify the various types of depth gauges
digital diaphragm capillary
The illustrated compass is a _______________ type A direct reading B indirect reading
direct reading
It is believed that nitrogen narcosis results from:
disruptions in the transmissions between nerve cells.
You can use a _______________ to keep nitrogen levels in your body within accepted limits A submersible pressure gauge B regulator C dive computer D surface float
dive computer
To minimize your risk of DCS you need
dive computer or dive tables
What situations dictate a need for a compass
diving in low visibility diving midwater diving at night when you cant use natural references to navigate
Decompression diving is what
diving that requires planned stops during ascent to avoid decompression sickness
Vertigo is a medical term meaning:
dizziness
The 60 minute halftime surface interval credit of the RDP gives approximately _________________ the surface interval credit of the 1950's version of the US Navy tables.
double RDP is 60 Navy is 120
In a regulator, a valve that tends to open in the direction of flow is referred to as ______________. This type of valve is considered to be a ___________ design.
downstream fail safe
A valve that tends to open in the direction of flow is referred to as _____________ while a valve that tends to close in the direction of flow is referred to as _____________. A open circuit/closed circuit B closed circuit/open circuit C upstream/downstream D downstream/upstream
downstream/upstream
If you are diving with a dive computer that does not display your cylinder pressure and it fails
during a dive, use your backup computer if you have one between dives, use your backup computer if you have been diving with one you may be able to resume diving using tables
Vertigo can be caused by:
ear squeeze, inner ear barotrauma in decompression sickness.
middle ear
eardrum to round window
Advantages dive computers have over dive tables include
easier dive planning and following the plan offsetting human error more time underwater
outer ear
ends at eardrum
Heat adds ____________ causing volume to ___________ in a flexible container or pressure to ____________ in an inflexible container. Cold has the opposite effect.
energy, increase, increase.
A/An _________________ operates by not allowing water to directly contact the first stage piston or diaphragm. A submersible pressure gauge B unbalanced valve C environmental seal D All of the above.
environmental seal
Measuring line, arm spans, tank pressure and elapsed time are all commonly used methods of _____________ underwater? Choose your answer. A navigating B estimating distance
estimating distance
some dive computers have added adjustments that reduce dive time or mandatory safety/decompression stops if you
exceed a safe ascent rate the water is cold make short surface intervals
Hypercapnia
excess carbon dioxide
When making a Controlled Emergency Swimming Ascent (CESA) the diver should __________________________ to avoid a lung-expansion injury. Choose your answer. A exhale forcefully B exhale lightly C exhale, making a continuous "ahhh" sound D "blow and go"
exhale, making a continuous "ahhh" sound
The carotid-sinus reflex is caused by an excessively tight_______________.
exposure suit or hood that constricts the neck
the carotid-sinus reflex is caused by an excessively tight_______________.
exposure suit or hood that constricts the neck
Three reasons to perform visual inspections each year
exterior damage interior corrosion especially in steel cylinder to prevent galvanic between the dissimilar metals of the cylinder and valve threads
Visual inspections should be done for high use cylinders and when any of the following occur
exterior is damaged cylinder is emptied during use increased weight burst disk fails air smells unusual valve is removed after long term storage after hydrostatic retest
middlle ear squeeze
failure to equalize or cold
One procedure to help you anticipate and prevent problems includes not worrying too much about small problems. Choose your answer. A True B False
false
The pressure sensor or transducer of a dive computer informs the computer of which decompression model or algorithm to use while diving
false
Contents sticker on a enriched air cylinder contain what
fill date oxygen % psi max depth analyzed by who's using tank
You know you are properly weighted for diving if you: Choose your answer. A float at neck level with your BCD about half full and you are holding a normal breath of air. B sink slowly holding a normal breath of air and an empty BCD. C float at eye level holding a normal breath of air with an empty BCD. D sink easily with a partially filled BCD.
float at eye level holding a normal breath of air with an empty BCD.
when diving with a computer
follow recommendations that apply to dive tables dont share with a buddy follow manufacturer recommendations
When flying after a dive with your computer, it's recommended that you ____________ or when the computer says you can fly - whichever is longer. A follow the dive medical community recommendations B wait 4 hours C wait 8 hours D None of the above
follow the dive medical community recommendations
When flying after a dive with your computer it is recommended that you
follow the dive medical community recommendations or when the computer says you can fly - whichever is longer
a dive computer
follows the same theoretical basis as dive tables calls for following the same general recommendations as when diving with tables should not be shared by two or more divers on a dive
round window rupture
forceful equallization - serious injury thaat can lead to hearing loss
Sound travels approximately _____ times faster in water than it does in air. Choose your answer. A two B four C ten D twenty
four
Sound travels _____ times faster in water than in air because water is so mutch _____ than air.
four / denser
Fail safe refers to a regulator's tendency to _____________ because of the use of a(n) _____________ valve in the second-stage. A breathe easily/open circuit B free-flow/downstream C breathe easily/closed circuit D free-flow/upstream
free-flow/downstream
Environmental seals helps keep regulators from
freezing in cold water
Silent bubbles are thought to form because of the presence of:
gas "seeds" (micronuclei)
Trimix
gas blend consisting of helium, oxygen, and nitrogen; the helium offsets narcotic properties of nitrogen at deep depths
Enriched air nitrox
gas blend consisting of nitrogen and oxygen, with the proportion of oxygen higher than 21 percent; used to accelerate decompression in tec diving
Capillaries
gas exchange takes place here / gives up oxygen and takes up co2 due to walls being supper thin and P2 tends to be less here.
capillaries
gas exchange takes place here / gives up oxygen and takes up co2 due to walls being supper thin and P2 tends to be less here.
Partial Pressure formula
gas percentage x ata = partial pressure ex: 21% O2 x 3ata = .63 ata
An SPG tells you how much what?
gas you have left in your cylinder at any time
capillary depth gauge and altitude
gives theoretical depths
If an oxygen service rated enriched air cylinder is filled with standard compressed air you should
have it serviced by someone qualified to to work on enriched air equipment before exposing it to more than 40% oxygen again
While on a dive in a mountain lake at an altitude of 3,000 metres/10,000 feet, a diver checks his depth. He is using a capillary depth gauge which indicates a depth of 14 metres/45 feet. If he actually measured the linear distance to the surface from where he is, he would find that: A he is exactly 14 metres/45 feet beneath the surface. B he is actually more than 14 metres/45 feet below the surface. C he is actually less than 14 metres/45 feet below the surface. D The answer cannot be determined from the data provided.
he is actually less than 14 metres/45 feet below the surface.
The best descent technique for natural navigation is to descend _________________________________. Choose your answer. A down a line B head up watching the bottom of the boat or the water's surface C head up with at least one buddy facing the direction of travel D None of the above.
head up with at least one buddy facing the direction of travel
Warning signs of CO poisoning
headache, confusion, narrowed vision
Radiation
heat transmission via a source.
Radiation
heat transmission via electromagnetic waves
Oxygen is efficiently transported throughout the body because of a substance called_________, which is contained in the____________.
hemoglobin / red blood cells
The symptoms of carbon monoxide poisoning are not as noticeable at depth because:
high levels of oxygen are dissolved into the plasma allowing tissues to meet their oxygen requirement.
the symptoms of carbon monoxide poisoning are not as noticeable at depth because:
high levels of oxygen are dissolved into the plasma allowing tissues to meet their oxygen requirement.
Name the parts of a valve
high pressure opening o ring for sealing regulator on off knob high pressure seat cylinder o ring burst disk debris or dip tube
Dive computers can tell you
how long you can stay at your current depth how long you can spend at a given depth on your next dive prescribe delays at specific depths as you ascend to allow excess nitrogen to leave your body
200X
how much faster does carbon monoxide bond to hemoglobin than does oxygen?
To ensure the structural integrity of a scuba tank, it should be _____________ anytime it is _____________. A destroyed/at an age of twenty years B hydrostatically tested/exposed to temperatures above 82ºC/180ºF C visually inspected/left unused for more than two years D All of the above are correct.
hydrostatically tested/exposed to temperatures above 82ºC/180ºF
If you ignore shivering and continue diving, as you continue to lose heat, your core temperature will drop, possibly leading to _________________. A heat stroke B decompression illness C hypothermia D cold exhaustion
hypothermia
If you ignore shivering and continue diving, as you continue to lose heat, your core temperature will drop, possibly leading to _________________. Choose your answer. A heat stroke B decompression illness C hypothermia D cold exhaustion
hypothermia
Cylinders must meet oxygen service standards
if bending method of mixing Enriched Air is used
Under what circumstances should a scuba cylinder be visually inspected
if loose material is heard red or green accumulation is seen on the first stage once every year even if cylinder is in good condition
carbon dioxide , air starvation, over exertion
if you breath rapidly and shortly it results in an increased in what? What affect does it have on you?
Collapsed lung
if you free dive when only holding half a breath or less what can this result in?
the practice of breathing deeply when scuba diving is important in order to compensate for the:
increase dead air space resulting from the snorkel or regulator. reducing lung volume resulting from compression of the chest. increased amount of alveolar carbon dioxide.
If a glass of water has been placed in pressure pot at 1 ata, what will happen if the pressure is raised to 2 ata? The gas pressure within the liquid will: Choose your answer. A increase. B decrease. C remain unchanged. D The answer cannot be determined from the data provided.
increase.
Overexertion
increases CO2
Breathing pure oxygen AIDS the individual with decompression sickness because it:
increases the pressure gradient between the nitrogen pressure in the tissue and the alveolar nitrogen pressure.
a compass with a reading that goes counter clockwise is a
indirect compass
The vegetable are canals are located in the________and are responsible for_________.
inner ear / balance
Hypocapnia
insufficient carbon dioxide
hypoxia
insufficient levels of oxygen (basically happens with free divers)
In terms of the location of symptoms, air embolism is characterized by______________, while decompression sickness is characterized by__________________.
involvement of only one side of the body ------------------------------------ involvement of both sides of the body, either upper or lower
Arrhythmia
irregular heart beat is called what?
Enriched Air requires a dedicated cylinder because
it can be hazardous to unknowingly dive with enriched air it can be hazardous to blend enriched air in a conventional air cylinder
a dive computer provides more no decompression time than a table because
it eliminates unnecessary rounding by calculating the dive exactly
The Recreational Dive Planner has shorter surface interval times and allows longer bottom times on repetitive dives than previous dive tables because:
it was designed using a faster "gas washout" tissue compartment
Water absorbs more heat than air because...
it's denser.
dead air space
its important to breath slowly and deeply in order to reduce...
You can use a dive computer to
keep nitrogen levels in your body within accepted limits
CESA procedure
keep reg in mouth b/c you could get extra air
Pulmonary oxygen toxicity
lengthy exposure to PO2 greater than 0.5 bar/ata
type 1 dcs
limb and joint pain, not immediately life threatening. This is what type of dcs
Plasma
liquid that carries nutrients , chemicals, and other blood components.
plasma
liquid that carries nutrients , chemicals, and other blood components.
pitting can weaken a cylinder structure
long before a hydro is due
Refraction causes objects to...
look closer by a 4:3 ratio;look 25% closer. - ex: A fish that is 4 ft away looks 3 ft away.
Oxygen is administered to a diver suspected of having decompression sickness to: Choose your answer. A lower the partial pressure of nitrogen in the lungs, which safely accelerates the diffusion of nitrogen from the blood. B decrease hypocapnia. C increase the metabolism of nitrogen. D ease the pain.
lower the partial pressure of nitrogen in the lungs, which safely accelerates the diffusion of nitrogen from the blood
Oxygen is administered to a diver suspected of having decompression sickness to: A lower the partial pressure of nitrogen in the lungs, which safely accelerates the diffusion of nitrogen from the blood. B decrease hypocapnia. C increase the metabolism of nitrogen. D ease the pain.
lower the partial pressure of nitrogen in the lungs, which safely accelerates the diffusion of nitrogen from the blood.
When setting a compass heading, the__________points in the direction of travel and you turn the______________ so the index marks are over the _________________. Choose your answer. A compass needle, bezel, lubber line B lubber line, compass needle, bezel C lubber line, bezel, compass needle
lubber line, bezel, compass needle
When applying a dressing and direct pressure to stop bleeding, if blood soaks through the dressing you should: (check all that apply) Choose your answer. A remove the dressing and reattempt the direct pressure with a fresh one. B maintain direct pressure and apply additional dressings over the first. C discontinue direct pressure and apply additional dressings over the first. D remove the dressing and apply a fresh one without direct pressure.
maintain direct pressure and apply additional dressings over the first.
jugular veins
major veins carrying oxygen poor blood from the brain.
Red blood cells
make up 45% of your blood
red blood cells
make up 45% of your blood
Mass
mass is a measure of matter based on the matter's inertia; can be used interchangeably with weight in diving because we only ever dive on earth...
M-value
max nitrogen level in a given tissue shorter halftime / faster compartment means lower M-value
if your dive computer fails
maximize safety stop
Absolute Pressure
measured pressure + atmospheric pressure
Gauge Pressure
measured pressure - atmospheric pressure
Which portion of the ear is most affected by changes in pressure?
middle ear
which part of the ear is most sensitive to pressure changes?
middle ear
the practice of breathing slowly went scuba diving is important in order to:
minimize resistance caused by turbulence in the airways.
ending in PG W or X
minimum SI of 1 hr
ending in PG Y or Z
minimum SI of 3 hrs
spencer limits, ee washout
model for dive computers calculating nitrogen elimination
Peripheral chemoreceptors
monitor oxygen level sand signal respiratory centers when a decline in the partial pressure of oxygen below a specific level is detected.
Open Circuit Scuba is the
most common type of recreational scuba equipment because it is ease to use and maintain when you inhale you breathe in gas from a cylinder and when you exhale it vents into the water
to reduce the demand for oxygen while breath-hold diving, the diver should:
move slowly and deliberately while underwater.
Six ___________ references commonly used to navigate underwater include light and shadows, water movement, noise, currents, bottom contours, bottom compositions and formations, and plants and animals. Choose your answer. A biological B natural C compass D sea water
natural
Predive observations that assist your _______________ include sun angle, waves, currents and tidal movement, and offshore objects. Choose your answer. A natural navigation B compass navigation
natural navigation
steel cylinder and weight difference
needs less weight
Central Nervous System oxygen toxicity
nervous system reactions to oxygen exposure; up to 1.4 bar/ata is within the acceptable range; 1.4-1.6 bar/ata is within contingency range; 1.6 and above is deemed hazardous and a high CNS risk.
pulmonary veins
newly oxoginated blood leaving the pulmonary capillaries flows to the .... where it's then transported to the left side of the heart.
Benefits of rebreathers
no bubbles more effective gas use
no stop dive is also called a
no decompression dive
Information all dive computers provide include
no decompression time remaining time depth ascent rate emergency decompression
There is _________________ relationship between Haldanean model and the human body; you can rely it only as far as it is supported as it is supported by?
no direct test and field data
anoxia
no oxygen at all in your system
No Decompression Limits are also called
no stop times
The first aid steps you should take for a patient with __________________ includes protecting the patient from excess heat or cold, arranging for emergency evacuation and medical care, keeping patient lying down and giving as close to 100 percent oxygen as possible. Choose your answer. A jellyfish stings B a stingray impalement C severe bleeding D None of the above.
none of the above its actually decompression illness
Normoxic conditions
normal oxygen conditions (P02 @ .21 bar/ata)
an environmental seal operates by
not allowing water to directly contact the first stage piston or diaphragm
Atomic number
number of protons in an atom
Charles Law
obsessed with tanks and temp - as the temp rises, the volume and density will increase - 1 degree Celcius change => 0.6 bar change
Carbon monoxide is difficult to detect because it is:
odorless and tasteless.
The term "demand valve" refers to the fact that the regulator will provide air: A during both inhalation and exhalation. B only upon inhalation. C only upon exhalation. D at a constant flow regardless of the inhalation effort.
only upon inhalation.
oval window
ossicles are attached to this membrane that flexes and allows the vibration to travel through a liquid in the cochlea.
Sound vibrations are transferred from the outer ear to the inner ear via the:
ossicles.
DCI
overall term that includes both dcs an lung over expansion injuries.
When does a burst disk rupture
past 140% of the cylinders working pressure
Skip breathing
pausing briefly before exhaling
Upstream valve
pilot valve moves AGAINST airflow
Downstream valve
pilot valve moves WITH airflow
using the RDP for cold water / strenuous conditions
plan 4m deeper
List the three primary signs and symptoms of nitrogen narcosis:
poor judgement, decreased coordination and a false sense of security.
Depending on the model you make activate your dive computer by
pressing a button touch contacts with moist fingers
The oil-filled bourdon tube analog depth gauge works by
pressure causing a sealed coil tube to coil tighter
The term barotrauma literally:
pressure injury (baro=pressure, trauma = injury)
Barotrauma is defined as a ____________ that may occur while diving during ___________. A back injury/back roll entries B pressure injury/either ascent or descent C decompression related injury/rapid ascents D pressure injury/ascent onl
pressure injury/either ascent or descent
Barotrauma is defined as a ____________ that may occur while diving during ___________. Choose your answer. A back injury/back roll entries B pressure injury/either ascent or descent C decompression related injury/rapid ascents D pressure injury/ascent only
pressure injury/either ascent or descent
The ___________________ of a dive computer informs the computer what depth it is at. A decompression algorithm B display C clock D pressure sensor/transducer
pressure sensor/transducer
reflex respiratory center
primary control of breathing
If your ________________ fails during a night dive, you should switch to your ______________ light and _____________ the dive. Choose your answer. A backup light/buddy's light/continue B primary light/backup/continue C primary/buddy's primary/abort D primary light/backup/abort
primary light/backup/abort
Oxidative metabolism
process in which cells use oxygen to convert chemical energy into usable energy
oxidative metabolism
process in which cells use oxygen to convert chemical energy into usable energy
Circulatory system
provides gas and nutrients to the body and eliminates waste.
Daltons law
psychological affect of gas is proportionate to the partial pressure.
The first step in setting up your dive computer is
reading the manufacturers instructions
The RDP was developed for ________________ divers. Its tests included ________________ divers, a wider range of ________________ and _______________ types
recreational, female, age and physical
The fundamental function of the first stage of an open circuit regulator is to: A reduce the intermediate pressure from the cylinder to a breathable pressure. B reduce the high pressure delivered by the cylinder to an intermediate pressure. C recycle usable breathing gases. D turn the air on and off from the cylinder.
reduce the high pressure delivered by the cylinder to an intermediate pressure.
The fundamental function of the second stage of an open circuit regulator is
reduce the intermediate air pressure to ambient pressure for breathing
What does the first stage regulator do
reduces high pressure to an intermediate pressure
A process called _________ refers to the tendency of light to ________ as it passes through two mediums with different densities. Choose your answer. A absorption/change color B refraction/bend C turbidity/weaken D diffusion/bend
refraction/bend
Actual bottom time is used in _____________ diving
repetitive
Using the RDP - generally a ____________ _______________ is a dive made within __________ hours of a previous dive
repetitive dive 6 hours
You should give ______________ to an unconscious, nonbreathing diver while towing to shore even if no pulse is suspected. Choose your answer. A CPR B a primary assessment C air D rescue breaths
rescue breaths
Actual Bottom Time is added to __________________ ________________ to account for the residual nitrogen from a previous dive. The sum gives you the total bottom time.
residual nitrogen time
pulmonary toxicity
results from continuous exposure to po2s above .5 bar.
gas narcosis
results from the blocking of nerve transmissions or gas blocking
Other than potential damage to the eardrum, and excessively forceful valsalva maneuver can result in a:
round window rupture.
Dive computer use is now the ____________ not the exeption
rule
If while descending a diver has difficulty with ear equalization, and forcefully blows against a pinched nose, the diver may risk: Choose your answer. A hypoxia. B rupturing his round window. C rupturing his eustachian tube. D getting a sinus squeeze.
rupturing his round window
If while descending a diver has difficulty with ear equalization, and forcefully blows against a pinched nose, the diver may risk: A hypoxia. B rupturing his round window. C rupturing his eustachian tube. D getting a sinus squeeze.
rupturing his round window.
To plan a dive with a computer
scroll through the No Decompression limits agree upon the deepest depth for the dive note the NDL for your planned depth and next deepest depth write down information; plan dives so maximum depths are progressively shallower
Enriched air guidelines that apply to all scuba equipment except cylinders are
scuba regulators BCD's SPG's Alternate Air Sources may be used with up to 40% oxygen without modification
When establishing a _____________ use natural boundaries, make it as large as possible, try to form a rectangle/square, and cover an area the ______ object's almost certainly in. Choose your answer. A search area/lost B dive site/lost C search area/natural D None of the above.
search area/lost
The component of an open circuit scuba regulator that reduces the intermediate air pressure to ambient pressure for breathing is: A second stage B first stage C Low pressure hose D burst disc
second stage
SCUBA stands for
self contained underwater breathing apparatus
Three areas of ___________ preparation include physical preparation, mental preparation, and equipment preparation. Choose your answer. A proper weighting B self-rescue
self-rescue
sever hypothermia
shivering stops, capillaries dilate, feels warm again, becomes drowsy, can go into respiratory arrest.
mild hypothermia
shivering, numbness in extremities, impaired muscle coordination.
A lift bag ________________ for recovering objects heavier than about 4 kg/10 lbs. Choose your answer. A is not approved B should be used C is never allowable D is an option
should be used
Shore diving entries
sideways into wave
bright red lips and nail beds, headache, confusion, tunnel vision, unconsciousness, death
signs and symptoms of carbon monoxide poisoning?
visual disturbances, ears ringing, nausea, muscle spasms, irritability, dizziness
signs and symptoms of oxygen toxicity following VENTID
discomfort in chest and irritating cough
signs and symptoms of pulmonary toxicity
The bubbles that may be present in a diver's circulation system, yet not cause any symptoms of decompression illness, are called: A invisible bubbles B alveolar bubbles C micronuclei D silent bubbles
silent bubbles
The bubbles that may be present in a diver's circulation system, yet not cause any symptoms of decompression illness, are called: Choose your answer. A invisible bubbles B alveolar bubbles C micronuclei D silent bubbles
silent bubbles
When diving with a cold or congestion, a diver may experience a squeeze on descent or a reverse block on ascent in the ___________. A sinuses B lungs C mask D outer ear
sinuses
When diving with a cold or congestion, a diver may experience a squeeze on descent or a reverse block on ascent in the ___________. Choose your answer. A sinuses B lungs C mask D outer ear
sinuses
Hang time
slang for time required for decomp stops
When the carotid-sinus receptors detect high pressure, they cause the heart to:
slow down.
when the carotid-sinus receptors detect high pressure, they cause the heart to:
slow down.
12X
smoking can raise carbon monoxide levels to what as much as normal?
make no more that one repetitive dive per day at altitude
so no more than 2 dives
Tachycardia
speeding up of heart rate is called what?
Guidelines to follow when diving with a computer include
staying well within limits following the most conservative computer watching your SPG ascend slowly and make safety stops
The (+) designation that appears on _____________ tanks denotes that the tank may be overfilled to _____________ beyond its working pressure. A steel/15% B aluminum/10% C steel and aluminum/10% D steel/10%
steel/10%
the (+) designation that appears on ______________cylinders denotes that the cylinder may be overfilled to _______________ beyond its working pressure
steele 10%
When overexerted in a currennt
stop, breathe, go slowly
A _________________ is used to tell you how much breathing gas you have left in your cylinder at any time. A depth gauge B pressure transducer C dive computer D submersible pressure gauge
submersible pressure gauge
A symptom of air embolism maybe________, well two symptoms of decompression sickness maybe _____________ and_____________.
sudden unconsciousness pain in the joints and fatigue
a symptom of air embolism maybe________, well two symptoms of decompression sickness maybe _____________ and_____________.
sudden unconsciousness pain in the joints and fatigue
The RDP uses a different basis for repetitive diving from that used by the 1950's US Navy tables because
surface interval credit can be less restrictive when limited to no decompression diving
Ambient Pressure
surrounding pressure, same as absolute
Ralph Erickson
swim coach and scuba instructor who co-founded PADI
In terms of the change in symptoms, air embolism is characterized by______________, while decompression sickness is characterized by________________.
symptoms tending to improve as a result of first aid ------------------------------------- usually no change or worsening of condition
to reduce the alveolar carbon dioxide level before a breath hold dive, the diver should:
take a few rapid, deep breaths before submerging.
A Submersible Pressure Gauge (PG) is used to
tell you how much breathing gas you have left in your cylinder at any time
The primary purpose of dive computer is to
tell you when you are near or have reached a No Stop Limit
The primary concern of using Enriched Air and scuba equipment is
that contact with high oxygen content may cause fire, explosion or deterioration
At 40 metres of salt water a flexible container is filled to only 1/5 of its capacity. If this container is taken to 20 metres, what will happen to the air volume inside? Choose your answer. A the volume will be the same at both depths. B the air volume will double. C the air volume will increase by 5/3. D the air volume will decrease by 3/5.
the air volume will increase by 5/3.
aorta
the body largest artery / has several branches that help send oxygen throughout the body. / main large tubes
Energy
the capacity to do work
Refraction
the change in direction when light passes from a medium of one density to a medium of a differing density; the speed of light changes causing a shift in its path
What may happen if a diver ruptures an eardrum while diving in cold water? A the diver may experience a squeeze. B the diver may lose consciousness. C the diver may experience vertigo. D the diver may experience euphoria.
the diver may experience vertigo.
What may happen if a diver ruptures an eardrum while diving in cold water? Choose your answer. A the diver may experience a squeeze. B the diver may lose consciousness. C the diver may experience vertigo. D the diver may experience euphoria.
the diver may experience vertigo.
What special considerations are important in terms of equipment when planning a deep dive?
the diver will use air more quickly than at shallower depth breathing will become more difficult than at shallower depth the diver may have difficulty controlling his ascent/decent
The term "open circuit" refers to the fact that: A electricity is used to test the regulator's air-flow rate. B the regulator is made from nonmagnetic metal. C the exhaled air is released directly into the water. D All of the above are correct.
the exhaled air is released directly into the water.
Shallow water blackout refers to unconsciousness that occurs during ascent from a breath-hold dive due to ________. Choose your answer. A supersaturation B the falling partial pressure of oxygen C increased carbon dioxide level D dive light failure
the falling partial pressure of oxygen
Shallow water blackout refers to unconsciousness that occurs during ascent from a breath-hold dive due to ________. Choose your answer. A supersaturation B the falling partial pressure of oxygen C increased carbon dioxide level D dive light failure
the falling partial pressure of oxygen
The primary concern of Enriched Air and your dive equipment is
the high oxygen content
No Stop Limit
the max time you can stay at a given depth and still ascend directly to the surface without making a decompression stop (aka no decompression limits or NDL)
Open circuit scuba systems
the most common type of recreational diving equipment easy to maintain and use vent exhaled gases into the water
convulsion
the most serious and obvious sign of cns oxygen toxicity is what?
aveoli, bloodstream
the nitrogen diffuses through the ..... walls and enters the ......
Blackout normally occurs on Ascent because:
the partial pressure of the alveolar oxygen rapidly decreases.
blackout normally occurs on Ascent because:
the partial pressure of the alveolar oxygen rapidly decreases.
What is the ascent rate
the proper speed for ascending which is no faster than 60 feet per minute. A slower rate is acceptable and appropriate
Slow deep breathing is best because: Choose your answer. A the proportion of dead air space to fresh air is reduced thus maximizing the usable air reaching the lungs. B air turbulence is decreased thus reducing breathing resistance. C the elimination of carbon dioxide is maximized. D All of the above are correct.
the proportion of dead air space to fresh air is reduced thus maximizing the usable air reaching the lungs. air turbulence is decreased thus reducing breathing resistance the elimination of carbon dioxide is maximized. D All of the above are correct.
Demand Valve refers to the fact that
the regulator will provide air - only on demand
Recreational scuba divers who ascend to altitude soon after completing a dive increase their risk of decompression sickness because: Choose your answer. A altitude sickness can contribute to the formation of nitrogen bubbles in the blood stream. B the partial pressure of inhaled oxygen is greater than the partial pressure of nitrogen in the tissues. C the surrounding pressure is less than the partial pressure of nitrogen in the tissues. D the surrounding pressure is greater than the partial pressure of nitrogen in the tissues.
the surrounding pressure is less than the partial pressure of nitrogen in the tissues.
Specific gravity
the tendency of a solid or liquid to float or sink in water; pure water is the standard and has a specific gravity of 1.0 Anything less dense than water will have a specific gravity less than 1.0 and will float because the upward force of buoyancy is greater than the downward pull of gravity.
Divers have difficulty determining the direction of sound underwater because: Choose your answer. A there is an insufficient delay between the sound striking one ear before the other. B water filling the ear canal reduces the ear's sensitivity to sound. C the wet suit hood makes it difficult to perceive sound as accurately as on land. D sound waves travel less efficiently underwater.
there is an insufficient delay between the sound striking one ear before the other.
Four advantages dive computers have over dive tables
they are easier to use offset human error give you more time underwater calculate enriched air profiles
The advantage of a balanced first stage over an unbalanced first stage is
they breathe easier at greater depths - even at low cylinder pressures provide greater air flow they are better able to a second diver breathing from an octopus
Differences between steel and aluminum cylinders are
thickness capacity pressure corrosion resistance
Steel scuba cylinders have
thinner walls and larger internal volume
ossicles
three small bones that magnify the vibrations in your ear that transfer it to the inner ear.
Approximately how much denser is the air a diver breathes at a depth of 20 metres as compared to the surface? Choose your answer. A equivalent to the surface density B two times as dense. C three times as dense. D four times as dense.
three times as dense.
Dissolved salts increase water densiity
throughout water mass
type 2 dcs
tingling, numbness, stroke like signs, unconsciousness, cardiac arrest. This is immediately life threatening. What form of dcs is this?
alveoli
tiny air sacs, carbon diffuses out and oxygen comes in through capillary and this wall.
Why do you need to know your maximum depth underwater
to avoid decompression sickness so you can remain within your planned depth and time limits
Why do you need to know the maximum depth of a dive and how long you've been under water
to avoid decompression sickness and remain within your planned depth and time limits
hit
to suffer oxygen toxicity or decompression sickness
hyperthermia
too much heat in the body is called what?
Atomic mass
total mass of particles in atom
A factor that determines the type of pattern to be used when conducting an underwater search includes the environmental conditions present at the search site. Choose your answer. A True B False
true
Visual reversal
turbidity can make things look farther away than they are
carotid arteries
two tubes from left aorta that brings oxygen rich blood to the brain.
All rebreathers recycle ______________ instead of allowing them to be wasted into the water
usable gases
All rebreathers recycle ________________ instead of allowing them to be wasted into the water. A carbon dioxide B bubbles C usable gasses D air
usable gasses
3 advantages of a open circuit demand valve regulator is
uses less air in a free flow system avoids carbon dioxide buildup by reducing dead air spaces simpler and less expensive than closed circuit systems
The symptoms of decompression sickness are ________ while the symptoms of a lung-expansion injury tend to appear _________. A usually are slower to occur/immediately after the dive B occur immediately upon surfacing/slowly over an extended time C appear within minutes after the dive/within the first 24 hours D usually appear at depth/only after surfacing
usually are slower to occur/immediately after the dive
The symptoms of decompression sickness are ________ while the symptoms of a lung-expansion injury tend to appear _________. Choose your answer. A usually are slower to occur/immediately after the dive B occur immediately upon surfacing/slowly over an extended time C appear within minutes after the dive/within the first 24 hours D usually appear at depth/only after surfacing
usually are slower to occur/immediately after the dive
To prevent a scuba tank from rupturing due to overpressurization, a burst disk is installed in the _____________, and is designed to rupture when the tank pressure rises above about _____________ of the tank's rated pressure. A regulator/200% B tank neck/225% C valve/140% D submersible pressure gauge/125%
valve/140%
You and your buddy cant share a dive computer because
variations of even a few meters/feet can affect time limits
eardrum rupture
vertigo and cold
At times, objects viewed underwater appear more distant than they actually are. This phenomenon is called "_________" and the factor that primarily influences its occurrence is ___________. Choose your answer. A distance perception/depth B diffusion/sunlight C visual reversal/turbidity D visual reversal/depth
visual reversal/turbidity
If a skin diver wants to increase breath-hold time on a surface dive, using _____________ will decrease the level of carbon dioxide in the lungs. A the Valsalva maneuver B the Frenzel maneuver C voluntary hyperventilation D the mammalian diving reflex
voluntary hyperventilation
If a skin diver wants to increase breath-hold time on a surface dive, using _____________ will decrease the level of carbon dioxide in the lungs. Choose your answer. A the Valsalva maneuver B the Frenzel maneuver C voluntary hyperventilation D the mammalian diving reflex
voluntary hyperventilation
Changing speed of light => distortion greatest factor
water -> glass -> air -> eyes
carbon dioxide
what causes us to breath involuntarily
Most RDP special rules, recommendations, and considerations comes entirely from
what diving has found to work whether they have any basis any basis in a decompression model or not
pulmonary toxicity
what does the cns clock help reduce?
middle ear
what is the air space in your ear called that you must equalize?
15 liters per minute
what should you set a continuous valve to flow at for emergency's.
carotid sinus reflex
when an vessel is constricted it can no longer transport blood to and from the brain. Raises blood pressure and drops heart rate, if blood pressure does not drop more it slows heart even more. This can cause fainting. What is this reflex called?
heat exhaustion
when body is working at full capacity to cool the body. Includes weak rapid pulse, profuse perspiration, cool and clammy skin, and nausea and weakness.
DCS
when dissolved nitrogen comes out of solution in tissues / what is this?
Laminar flow
when gas flows through smooth passages and travels uninterrupted
hypothermia
when the body becomes too cold
Why do you need a compass
when you cant use natural references to navigate in poor visibility at night in midwater
left side
where does the blood first enter the heart?
pulmonary capillaries
where the pulmonary artery brings oxygen poor blood to release Co2 or nitrogen from the system.
In Europe a enriched air cylinder may have what markings
white should with black stripe
can impair circulation
why are illnesses and injuries a predisposing factor?
circulatory system slows down
why is age a predisposing factor?
prompts dehydration, alters blood flow, capillaries dilate
why is alcohol a predisposing factor?
reduces circulation
why is cold water a predisposing factor?
impairs circulation, alters blood flow, and nitrogen elimination
why is dehydration considered a predisposing factor?
may causes nitrogen bubbles to form
why is exercise (before, after, or during a dive) a predisposing factor?
nitrogen is more soluble in fat than in water
why is fat tissue a predisposing factor?
you go beyond the models constraints
why is flying to soon a predisposing factor
you become more susceptible to dcs
why is having a history of dcs (you got it once) a predisposing factor?
the two basic types of cylinder valves used today are
yolk DIN
4 slow deep breaths
you can reduce carbon dioxide levels in free diving by doing what?
