Which term describes the ability of a substance to float in a fluid?

• A. Mass
• B. Weight
• C. Buoyancy
• D. Density

Answer: (C)

Buoyancy describes the upward force a fluid exerts on an object immersed in it. By Archimedes’ principle, this buoyant force equals the weight of the fluid displaced. Whether the object floats depends on the balance between this upward buoyant force and the object's weight. If buoyancy is greater, the object rises; if it matches weight, it’s neutrally buoyant; if it’s less, it sinks. Density matters because it influences how much fluid is displaced for a given volume, but the term that specifically captures the ability to float is buoyancy.