What is specific gravity of a liquid or solid?

The specific gravity of a liquid or solid is defined as the ratio of the mass of a given volume of that substance to the mass of an equal volume of water. This definition is foundational in understanding how materials behave in a fluid medium. Specific gravity is a dimensionless quantity, meaning it has no units, and it provides insight into the relative density of substances.

When you determine specific gravity, you typically compare the density of the substance in question to the density of water (which is 1 g/cm³ at 4°C). If the specific gravity is greater than 1, the substance will sink in water, while if it is less than 1, it will float. This property is significant in various applications, including fire investigations, where understanding the behavior of liquids and solids relative to water can aid in determining the nature of materials involved in an incident.

Understanding the precise definition helps in correctly analyzing scenarios involving fires and explosions, where the behavior of various materials can impact the investigation and understanding of what occurred during the incident. The other choices do not accurately capture the definition of specific gravity, as they either misrepresent the relationship with water or focus on aspects like buoyancy or density comparisons that do not align with standard definitions in physical science.