The ratio of the weight of a solid or a liquid substance to the weight...

The ratio of the weight of a solid or a liquid substance to the weight of an equal volume of water is referred to asspecific gravity. Specific gravity is a dimensionless quantity that is defined as the ratio of the density of a substance to the density of the water at a specified temperature.The density of water at 4 0C is commonly used as a reference point1. Specific gravity can be calculated using the following formula:

SG=fracrhosubstance​rhoH2​O​

where rhosubstance​ is the density of the substance and rhoH2​O​ is the density of water. Specific gravity can be used to compare the relative densities of different substances and to determinewhether a substance will sink or float in water.A substance with a specific gravity less than 1 will float in water, while a substance with a specific gravity greater than 1 will sink in water2.

For example, the specific gravity of gold is 19.3, which means that gold is 19.3 times denser than water. Therefore, gold will sink in water. The specific gravity of ice is 0.92, which means that ice is 0.92 times denser than water. Therefore, ice will float in water.

References:

Specific gravity | Formula, Units, & Equation | Britannica

Specific Gravity - Definition, Calculation, Solved Examples, FAQs - BYJU’S