In buoyancy, which property determines whether an object sinks or floats in a fluid?

• A. Its color.
• B. Its temperature alone.
• C. The density relative to the fluid determines floating or sinking.
• D. Its mass only.

Answer: (C)

Buoyancy depends on how dense an object is compared with the fluid it’s in. The upward buoyant force from the fluid equals the weight of the fluid displaced. An object will float if this upward force can balance or exceed its weight, which happens when the object’s density is less than the fluid’s density. If the object is denser than the fluid, it sinks; if the densities are the same, it can stay suspended. So the key factor is the density relative to the fluid, which directly determines whether the displaced fluid provides enough support.

Color has no effect on buoyancy, since it doesn’t change density or the forces involved. Temperature can change densities, but it isn’t the standalone predictor of sinking or floating—the actual densities relative to the fluid matter. Mass alone doesn’t determine buoyancy, because two objects with the same mass can have very different volumes and densities, leading to different outcomes in a fluid.