Which term defines the ratio of the density of a substance to the density of water for liquids and solids?

Which term defines the ratio of the density of a substance to the density of water for liquids and solids?

• A. Specific Gravity
• B. Specific Gravity of Air
• C. Relative Density
• D. Mass Density

Answer: (A)

Specific gravity is the ratio of a substance’s density to the density of water, and for liquids and solids this ratio is dimensionless. Water provides a convenient reference because its density is about 1 g/cm^3 (at 4°C), so the specific gravity value basically tells you how dense the substance is compared with water. For example, a material with density 2 g/cm^3 has a specific gravity of about 2, meaning it’s twice as dense as water; a substance with density 0.5 g/cm^3 has a specific gravity of 0.5, meaning it’s half as dense as water. This term is the standard way to express how heavy a liquid or solid is relative to water, which is why it’s the best choice here. The other options describe related ideas but don’t match the exact definition: density relative to air isn’t the same reference, mass density is the actual density value, and while relative density is sometimes used interchangeably, the conventional term for this ratio with water in liquids and solids is specific gravity.

Specific gravity is the ratio of a substance’s density to the density of water, and for liquids and solids this ratio is dimensionless. Water provides a convenient reference because its density is about 1 g/cm^3 (at 4°C), so the specific gravity value basically tells you how dense the substance is compared with water. For example, a material with density 2 g/cm^3 has a specific gravity of about 2, meaning it’s twice as dense as water; a substance with density 0.5 g/cm^3 has a specific gravity of 0.5, meaning it’s half as dense as water. This term is the standard way to express how heavy a liquid or solid is relative to water, which is why it’s the best choice here. The other options describe related ideas but don’t match the exact definition: density relative to air isn’t the same reference, mass density is the actual density value, and while relative density is sometimes used interchangeably, the conventional term for this ratio with water in liquids and solids is specific gravity.