How do you find specific gravity of a substance?
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 = Ïobject / ÏW
Ïobject = density of the material (kg/m3 or g/cm3)
ÏW = 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.
Ïobject = 28,000 g/cm3
ÏW = 1000 g/cm3
Step 2: Substitute the values in the formula to find the relative density of the given object.
SG = Ïobject / ÏW
= 28,000 / 1000
Specific gravity / Relative Density =28