What does specific gravity measure?

• A. The weight of a gas compared to air
• B. The weight of a liquid compared to water
• C. The boiling point of a solution
• D. The density of a solid

Answer: (B)

Specific gravity is a dimensionless quantity that measures the weight of a substance compared to the weight of an equal volume of water at a specific temperature (usually 4 degrees Celsius, where water is densest). When we refer to specific gravity in the context of liquids, we are specifically comparing the density of the liquid to the density of water. A specific gravity less than 1 indicates that the liquid is less dense than water and will float, while a specific gravity greater than 1 indicates that it is denser than water and will sink.

This property is particularly important in hazardous materials management because it helps assess the behavior of liquids in various situations, such as spills or leaks, and aids in determining appropriate response measures. Knowing the specific gravity can also inform responders if a hazardous liquid will spread or remain in a localized area. Understanding these physical properties is essential when dealing with hazardous materials to ensure safety and effectiveness in response efforts.