Oilers/Plant Tenders (HHC) Civil Service Practice Exam

How is the specific gravity of a lubricant commonly measured?

1. Using a hydrometer

2. Using a gravimetric balance

3. Using a viscometer

4. Using a Saybolt viscometer

The correct answer is: Using a Saybolt viscometer

The specific gravity of a lubricant is commonly measured using a hydrometer. A hydrometer is an instrument that measures the density of liquids, which can be used to calculate specific gravity by comparing the density of the lubricant to that of water at a standardized temperature. The other methods mentioned are not suitable for directly measuring specific gravity. A gravimetric balance measures mass but does not provide density or specific gravity information unless used in conjunction with volume measurements. A viscometer measures viscosity, which is the resistance of a fluid to flow, and does not directly relate to specific gravity. Similarly, a Saybolt viscometer is specifically designed to measure the viscosity of liquids, particularly oils and fuels, and does not provide the necessary parameters to determine specific gravity.