What factors influence a diver's buoyancy?

Buoyancy in diving is primarily influenced by several physical factors, of which the diver's weight, equipment, and changes in gas volume with depth are the most significant.

A diver’s weight plays a critical role as it affects how much weight is needed to counteract buoyancy from both the diver's body and equipment. If a diver is heavier than the weight of the water they displace, they will sink; conversely, if they are lighter, they will float.

Equipment such as wetsuits, dive tanks, and buoyancy control devices (BCDs) also directly affect buoyancy. For instance, a wetsuit traps air, which increases buoyancy, while a full tank of air is denser than the water, but as it is depleted, the diver becomes lighter.

Changes in gas volume with depth due to pressure also impact buoyancy. According to Boyle's Law, gas volume decreases as pressure increases. Therefore, as a diver descends and pressures rise, the air in their lungs and buoyancy devices compresses, causing the diver to be less buoyant.

In contrast, although water temperature and visibility may affect the comfort and safety of a dive, they do not directly influence buoyancy. Similarly, the diver's experience