IANTD Open Water Diver Practice Exam

As a diver descends in water, the absorption of light is heavily influenced by the properties of water. The correct answer highlights that the light spectrum, represented by the acronym ROYGBIV (Red, Orange, Yellow, Green, Blue, Indigo, Violet), is progressively absorbed at different depths. The first colors to be absorbed are the reds and oranges, which can vanish completely within the first few feet of a dive. As a diver goes deeper, the remaining colors from the spectrum are absorbed at varying depths, with blues being the last to be seen.

This phenomenon is crucial for divers to understand because it affects visibility and the perception of the underwater environment. For instance, deeper environments can create a monochromatic view where mainly blue and green hues are visible, altering how objects are perceived in the underwater landscape. Understanding this helps divers appreciate the changing environment as they descend and prepares them for the variations in color that they will experience.