Specific Gravity
Specific Gravity
Specific gravity compares a fluid’s density to water, a quick dimensionless way to identify and compare liquids.
The specific gravity is SG = ρ/ρ_w. where ρ is the fluid density and ρ_w the density of water.
Inputs
rho := 850 kg/m^3=850 kg/m^3
rho_w := 1000 kg/m^3=1000 kg/m^3
Divide fluid density by water density.
SG := rho/rho_w=0.85
Results
An SG below 1 (here 0.85) means the fluid floats on water; above 1 it sinks. Hydrometers read this directly.
Assumptions & limitations
- Referenced to water at 4 °C.
- Same temperature basis.
- Dimensionless.