How to Calculate Specific Gravity?

How do you find specific gravity of a substance?

Specific Gravity Step by Step Calculation

Specific gravity is a dimensionless quantity. It is a measure of ratio of density of a substance to the density of water at 4 degrees Celsius. It can be represented as sp gr. and can also be termed as relative density. Specific density of the water is 1000 kg/m³. If the substance referred has specific gravity less than 1, then its less denser than water and if greater than 1, more denser than the water.

Formula
SG = ρ_object / ρ_W
ρ_object = density of the material (kg/m³ or g/cm³)
ρ_W = density of the water (kg/m³ or g/cm³)

Specific density of water is 1 kg/m³ or 1000 g/cm³. Substance referred in the numerator and denominator always holds the same unit. Thus, relative density doesnt have any unit.
Step 1: Consider an example, the density of the object is 28,000 g/cm³ and the density of water is 1000 g/cm³.
ρ_object = 28,000 g/cm³
ρ_W = 1000 g/cm³

Step 2: Substitute the values in the formula to find the relative density of the given object.
SG = ρ_object / ρ_W
= 28,000 / 1000
Specific gravity / Relative Density =28

Related Topics