A block with density 2.0 g/cm³ is placed in water (density 1.0 g/cm³). Will the block float or sink, and why?

A block with density 2.0 g/cm³ is placed in water (density 1.0 g/cm³). Will the block float or sink, and why?

• A. Float
• B. Sink
• C. Hover
• D. Dissolve

Answer: (B)

Density tells you how heavy something is for its size, and buoyancy depends on how much water you can push out of the way. Water has a density of 1.0 g/cm^3, so the upward buoyant force equals the weight of the water displaced. If the block is denser than water, its weight for the same volume is greater than the buoyant force the water can provide, so gravity wins and the block sinks. With a density of 2.0 g/cm^3, this block is heavier per volume than water, so it will sink rather than float, hover, or dissolve.

Density tells you how heavy something is for its size, and buoyancy depends on how much water you can push out of the way. Water has a density of 1.0 g/cm^3, so the upward buoyant force equals the weight of the water displaced. If the block is denser than water, its weight for the same volume is greater than the buoyant force the water can provide, so gravity wins and the block sinks. With a density of 2.0 g/cm^3, this block is heavier per volume than water, so it will sink rather than float, hover, or dissolve.