What is Specific Gravity?

Specific gravity is a numerical value that is used to determine the relative density of a liquid or solid when compared to a reference substance. Specifically, it is the ratio of a material’s density to that of water, which is assigned a value of 1.000. Simply put, specific gravity is a measure of the “heaviness” of a material, and is often used in quality control. Additionally, it is a helpful tool to determine the various concentrations of solutions.

Measuring Specific Gravity

The most common way to measure the specific gravity of a material is the use of a hydrometer. A hydrometer is a glass device with a series of floating scales, graduations, and a weighted bulb at the bottom that allows the hydrometer to float on the surface of the liquid being tested. The hydrometer should be placed in a cylinder of the material so that it can float freely. As the hydrometer floats, it will sink down depending on the density of the liquid in the cylinder. The reading can then be taken where the surface of the liquid and the weighted bulb meet on the hydrometer.

Using Specific Gravity

Specific gravity measurements are often used in multiple industries such as aerospace, electricity, and plumbing. One common use is to measure the relative density and concentration of electrolyte solutions in lead-acid batteries. Knowing the specific gravity of the solution and predicting the resulting behavior is an effective way to predict a battery’s performance. This same concept can be applied to other fields in order to measure various densities and concentrations.

Overall, specific gravity is an invaluable tool for measuring and understanding the relative densities of materials. With its ability to measure certain concentrations, it is a helpful resource for industries like aerospace, electricity, and more. It can be used to measure the relative densities of a variety of materials, such as liquefied petroleum gas, and lead-acid batteries. In some cases, such as lead-acid batteries, specific gravity can be a useful tool in predicting performance.