An object that floats in a fluid is known as being positively buoyant. An object that sinks to the bottom is negatively buoyant, while an object that remains in balance at the same level in the fluid is neutrally buoyant. Ways to adjust buoyancy were developed to produce equipment such as the inflatable life jacket, which is filled with gas and helps to reduce a person's average density, assisting in floating and swimming, as well as certain diving equipment (including submarines and submersibles) which have adjustable volume air chambers to regulate buoyancy.
An object that floats in a fluid is positively buoyant, while one that sinks is negatively buoyant. An object at equilibrium has neutral buoyancy. Devices like inflatable life jackets and diving equipment use adjustments to their volume of gas or air to control buoyancy.