What determines whether an object sinks or floats in water?

What determines whether an object sinks or floats in water?

• A. If its density is greater than water's density, it sinks; if less, it floats.
• B. If its mass is greater than water's mass.
• C. If it changes temperature.
• D. If it dissolves in water.

Answer: (A)

The deciding factor is the object's density relative to water. According to Archimedes’ principle, the buoyant force equals the weight of the water the object displaces. If the object is denser than water, its weight is greater than the buoyant force from the displaced water, so it sinks. If the object is less dense than water, the buoyant force is enough to support it, and it floats. Temperature can shift water’s density a bit, which can change things under different conditions, but the fundamental rule is density comparison. Dissolving changes mass or surface interactions but doesn’t override the basic density criterion.

The deciding factor is the object's density relative to water. According to Archimedes’ principle, the buoyant force equals the weight of the water the object displaces. If the object is denser than water, its weight is greater than the buoyant force from the displaced water, so it sinks. If the object is less dense than water, the buoyant force is enough to support it, and it floats. Temperature can shift water’s density a bit, which can change things under different conditions, but the fundamental rule is density comparison. Dissolving changes mass or surface interactions but doesn’t override the basic density criterion.