SDI Scuba Certification Exam Study Guide questions with correct answers

Define SCUBA S - self C - contained U - underwater B - breathing A - apparatus List 3 important scuba diving changes that occurred in 1950s 1) published USN dive tables 2) invented the personal dive computer 3) equipment manufacturers made improvements to the design and workmanship of gear Name 3 different devices that modern dive computers replace 1) dive tables 2) J-valves 3) depth gauges What sets SDI apart from other training agencies? First dive training agency to provide entry level scuba instruction that incorporates the use of personal dive computers -- more streamlined scuba course w/ more instruction time in the water How much larger and closer do objects appear underwater and why? Objects underwater appear 25% larger and 25% closer As light travels through the airspace created by the mask, it bends, creating a magnifying effect. How much faster does sound move through water than air and why? 4 times faster because water is about 800 times denser than air. What is the first color to be absorbed underwater? Red (within first 25 feet) When diving from shore, the best time to dive is when there is the least amount of tidal current. _______ tide is when there is no horizontal water movement. Slack tide If you are caught in a rip current, first swim _____ to the current to get out of it before swimming towards shore. Parallel