PADI IDC Study Guide Questions With Complete Answers.

Recreational diving - correct answer 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. No Stop Limit - correct answer 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) Decompression sickness - correct answer "the bends" - a condition caused when gas bubbles form in the body after a dive Decompression stop - correct answer a pause or pauses in ascent at a specific depth and time to allow the body to release dissolved gas and avoid decompression sickness Safety stop - correct answer 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 PADI - correct answer Professional Association of Diving Instructors; established in 1966 Deep Dive - correct answer 100 feet (30 metres) or deeper PADI Master Scuba Diver - correct answer PADI Rescue Diver who has earned 5 specialties. PADI Junior Certifications - correct answer 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. PADI Seal Team and Bubblemaker - correct answer 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. Subdivisions of Tec Diving - correct answer Deep diving; trimix diving; cave diving; technical wreck diving; technology-specific diving Tec Diving definition - correct answer 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 Hang time - correct answer slang for time required for decomp stops Accelerated decompression - correct answer Switching to gas blends high in oxygen, or pure oxygen, to shorten the required decompression time Trimix - correct answer gas blend consisting of helium, oxygen, and nitrogen; the helium offsets narcotic properties of nitrogen at deep depths Enriched air nitrox - correct answer gas blend consisting of nitrogen and oxygen, with the proportion of oxygen higher than 21 percent; used to accelerate decompression in tec diving oxygen toxicity - correct answer convulsions caused by oxygen at depth; safe limits determined by the proportion of oxygen in the gas and the depth CCR - correct answer closed-circuit rebreather, a form of scuba that is more efficient because it recycles exhaled gases instead of releasing them as bubbles hit - correct answer to suffer oxygen toxicity or decompression sickness Technical deep diving - correct answer 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. Trimix diving - correct answer 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). Cave diving - correct answer Typically shallower; main danger is far from air/light source and stirring up silt. Sidemount diving - correct answer Typically used in cave diving; divers ear separate cylinders on one or both sides, which allows for movement through very small areas more easily. Technical wreck diving - correct answer Entering the structure of a sunken ship and penetrating beyond 130 linear feet from the surface Technology-specific diving - correct answer Includes training with long-distance diver propulsion vehicles or CCRs NAUI - correct answer National Association of Underwater Instructors John Cronin - correct answer Scuba manufacturer rep who co-founded PADI Ralph Erickson - correct answer swim coach and scuba instructor who co-founded PADI Benoit Roaquayrol - correct answer Developed first open circuit demand scuba in 1865 with Auguste Denayrouze Auguste Denayrouze - correct answer Developed first open circuit demand scuba in 1865 with Benoit Rouquayrol Henry A. Fleuss - correct answer In 1879, he developed first practical working scuba - an oxygen rebreather that did not differ much from modern oxygen rebreathers. Louis Boutan - correct answer Took first underwater photographs by a diver in 1892. John Scott Haldane - correct answer Published first dive tables in 1908. Louis de Corlieu - correct answer Invented first rubber fins for swimming in 1933. Emile Gagnan - correct answer Co-developed the open circuit compressed air regulator with Jacques Cousteau in 1943. Conshelf I - correct answer Founded by Jacques Cousteau, the project entailed two divers spending 1 week in 33 feet of water. Conshelf II - correct answer Five divers lived at 36 feet for one month in the Red Sea. Phil Nyutten - correct answer Patented oil-filled rotary joint for hard suits, which becomes the basis of the Newt Suit. Raymond E. Rogers - correct answer Developed the Recreational Dive Planner Atomic mass - correct answer total mass of particles in atom Atomic number - correct answer number of protons in an atom Isotopes - correct answer Atoms of an element that have a different number of neutrons (but same number of protons) Molecular elements - correct answer compounds that consist entirely of atoms from a single element Reactive (chemistry) - correct answer 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. Stable (chemistry) - correct answer 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. Ionic bonding - correct answer One atom takes an electron from another atom to complete its outer shell (e.g. NaCl) Covalent bonding - correct answer Atoms share electrons to complete their outer shell (e.g. water)