Measure the weight of the substance in air
Measure the weight of an equal volume of water
Divide the weight of the substance by the weight of the same volume of water
Use the formula: Specific Gravity = Density of substance ÷ Density of water
Use the formula: Specific Gravity = Weight of substance in air ÷ Loss of weight in water
Ensure both measurements use the same units
For liquids, use a hydrometer or a pycnometer
For solids, use displacement or immersion methods
For gases, compare density to the density of air or another reference gas