What is the definition of specific gravity?

The definition of specific gravity is indeed the ratio of the mass of a substance to the mass of an equal volume of water at 4°C. This definition is significant because it allows for the comparison of the density of a material directly with that of water, which is a standard reference point due to its well-known properties. At 4°C, water reaches its maximum density, making it an ideal substance for this comparison.

Specific gravity is a dimensionless quantity, meaning it has no units, since it is a ratio of like measurements (mass/volume). When determining specific gravity, one can assess whether a substance will float or sink in water; a specific gravity greater than 1 indicates the substance is denser than water and will sink, while a specific gravity less than 1 indicates it is less dense and will float.

Other options do not accurately capture the concept. For example, one option discusses the total weight of a substance divided by its volume, which refers to density rather than specific gravity. Another option compares the density of a liquid to that of air, which is not relevant to specific gravity since specific gravity specifically involves the comparison to water. Lastly, one option uses the mass of water at room temperature, which is not the standard reference for