Scuba Diving Final Exam Questions and Answers 2024

What will the buoyancy of an object be (positive, neutral, or negative) if it displaces an amount of water: a. more than its own weight? b. less than its own weight? c. equal to its own weight? - a. positive b. negative c. neutral How does the buoyancy of an object differ in fresh water compared to salt water. - Because salt water weighs more than fresh water, it causes more buoyancy (more upward force) What is the relationship between increasing and decreasing depth and water pressure? - With increasing depth the water pressure increases. With decreasing depth the water pressure decreases. What are the absolute pressures, air volume, and air density in atmospheres, for: a. 10m/33ft b. 20m/66ft b. 30m/99ft c. 40m/132ft - a. 2 bar/ata, 1/2, x 2 b. 3 bar/ata, 1/3, x 3 c. 4 bar/ata, 1/4, x4 d. 5 bar/ata, 1/5, x5 What is the relationship between air volume and density, and how do they vary according to this relationship when pressure increases or decreases? - Air volume and density change proportionately with pressure. As pressure increases, air volume decreases, and air density increases. As pressure decreases, air volume increases, and air density decreases. What is a "squeeze"? - A pressure imbalance that pushes tissues into an air space. What is "equalization"? - The process of adding air to an air space. What are the three ways you can equalize air spaces during descent? - 1. pinch your nose and blow gently against it 2. wiggling your jaw side-to-side and swallowing 3. blow air into mask through your nose How often should you equalize during descent? - Frequently What three steps should you take if you feel discomfort in an air space while descending? - 1. stop your descent 2. signal your buddy(ies) 3. ascend slightly until the discomfort passes and try again What is the most important rule in scuba diving? - to breathe continuously and never, ever hold your breath What are the consequences of breaking the most important rule in scuba diving? - lung overexpansion injuries How does increasing depth affect how long your air supply lasts? - it shortens it What's the most efficient way to breathe dense air underwater? - take slow, deep breaths When selecting scuba equipment, what are the three most important factors? - suitability, fit, and comfort How do you prepare a new mask for use? - you may need to scrub the interior of the glass with a mask cleaner. main preparation is to adjust the strap. fit it over the crown of your head, above your ears, with a snug but not overly tightly fit. secure the strap locking device if it has one. What are two basic types of tank valves? - yoke and DIN What's the difference between a DIN valve and a yoke valve? - the yoke system holds the first stage to the cylinder with a clamp system. with the DIN system, the regulator threads into the valve. What's the best way to keep water out of a scuba tank? - to never completely empty it and store the cylinder in a standing position. Why do you need scuba tank visual inspections and pressure tests and how often are they done? - to keep the maintenance of the cylinder and to know it is properly working. the visual inspection is done annually. the pressure test is done every two to five years. How does looking at something underwater affect its apparent size? - the make them looker larger and/or closer How does water affect light intensity and color? - as you go deeper, it gets darker and colors start to fade.