What is specific gravity? How to measure it?

What is specific gravity?

Specific gravity, called Relative Density, is a measurement used to define the weight or Density of a substance compared to the Density of an equal volume reference material at a specified temperature.

In most cases, the reference material is liquid water or gaseous air. The specific gravity represents a ratio and is therefore dimensionless.

The specific gravity of liquids is almost always measured with reference to water at a temperature of 4 ℃ or 39.2 ° F; the specific gravity of gases is almost always measured with reference to air at room temperature of 20 ℃ or 68 ° F.

How to measure specific gravity?

Specific gravity is a measure of the Density of a substance and can be used to distinguish between solids and liquids. The greater the Density of a substance, the stronger it is.

1. The Density of liquid water is 0.997, so if we weigh a glass of water and then weigh the glass of water after adding a substance, we can determine the Density of water by the following formula:

Water weight - water weight + substance

2. The specific gravity of solids and liquids

Water is the liquid with the highest known Density. We know that water has a specific gravity of 1.000. Dense substances have a specific gravity of 1.000 or higher. So substances with high Density are called solids, and substances with low Density are called liquids.