SDI Open Water Scuba Diver Practice Exam

A mask must cover the nose while scuba diving for several important reasons. Firstly, covering the nose ensures a better fit, which is crucial for maintaining a good seal. A proper fit prevents water from entering the mask, a common issue that can disrupt a diver's experience underwater.

Additionally, a mask that covers the nose allows for equalization of pressure. As a diver descends, water pressure increases, and air spaces in the mask can create discomfort if not equalized. By covering the nose, divers can exhale through it to equalize the pressure between the inside of the mask and the outside environment, minimizing discomfort and preventing mask squeeze.

These factors are collectively important for maintaining comfort, safety, and visibility while diving, making it essential for performance underwater.