Why does saltwater make an object float more easily than freshwater?

Why does saltwater make an object float more easily than freshwater?

• A. Saltwater is denser
• B. Saltwater is warmer
• C. Saltwater is more viscous
• D. Saltwater contains more oxygen

Answer: (A)

Buoyancy depends on density. When an object is placed in a liquid, it must push aside that liquid, and the liquid pushes back with a buoyant force equal to the weight of the displaced fluid. Saltwater is denser than freshwater because of the dissolved salts. Since a given volume of saltwater weighs more, it can support more weight before the object sinks. In other words, the same object experiences a stronger upward push in saltwater, making it float more easily. Warmer water can actually be less dense, so it wouldn’t increase buoyancy; viscosity and dissolved oxygen don’t change the buoyant force in the same way.

Buoyancy depends on density. When an object is placed in a liquid, it must push aside that liquid, and the liquid pushes back with a buoyant force equal to the weight of the displaced fluid. Saltwater is denser than freshwater because of the dissolved salts. Since a given volume of saltwater weighs more, it can support more weight before the object sinks. In other words, the same object experiences a stronger upward push in saltwater, making it float more easily. Warmer water can actually be less dense, so it wouldn’t increase buoyancy; viscosity and dissolved oxygen don’t change the buoyant force in the same way.