Course Outline

The physical world can have a very significant impact on the way a diver moves, sees, hears, and feels underwater. Additionally, there are physiological effects that will be discussed further here.

Understanding the physics that causes these impacts is critical to the safety and enjoyment of diving. Here are some examples.

  • Water density causes drag and effectively decreases your ability to move freely.
  • Colors appear different because some of them are absorbed by water.
  • Water is a much better conductor of heat than air. As a result, we lose heat much more quickly in water.
  • Most importantly, at sea level, water weighs about 800 times more than air. Therefore, as you descend underwater, you are quickly subjected to pressure. This greatly affects the gases inside the human body.

You do not need to understand every part of every law or equation, but you must understand what it all means to you and your body when you are underwater. You should talk to a dive professional at your dive center if you need help understanding this unit.

The following are the unit objectives.

  • Explain some of the physical effects on divers underwater
  • Describe the states of buoyancy
  • Explain pressure, volume, and density relationships
  • Describe the effects on light and sound underwater
  • Explain how to calculate surface air consumption rates (SAC)
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