What tool is used to measure the viscosity of oil?

What tool is used to measure the viscosity of oil?

• A. Saybolt Universal Viscometer
• B. Viscosity cup
• C. Hydrometer
• D. Infrared thermometer

Answer: (A)

Viscosity is how resistant a liquid is to flowing, and for aviation oils the Saybolt Universal Viscometer is the instrument used to measure that property at a specified temperature. It works by heating the oil to the test temperature, letting it flow through a calibrated capillary, and timing how long a fixed volume takes to discharge into a collection container. The flow time increases with thicker oils, so longer times indicate higher viscosity. The result is reported as Saybolt Universal Seconds at the chosen temperature, which provides a standard, comparable measure for petroleum products. This method is preferred because it directly assesses flow behavior of oil under controlled conditions and is widely standardized for aviation and other petroleum oils. A viscosity cup offers only a rough, less precise time-to-flow method and isn’t the standard for engine oils. A hydrometer measures density, not viscosity, and an infrared thermometer only reads temperature, not viscosity.

Viscosity is how resistant a liquid is to flowing, and for aviation oils the Saybolt Universal Viscometer is the instrument used to measure that property at a specified temperature. It works by heating the oil to the test temperature, letting it flow through a calibrated capillary, and timing how long a fixed volume takes to discharge into a collection container. The flow time increases with thicker oils, so longer times indicate higher viscosity. The result is reported as Saybolt Universal Seconds at the chosen temperature, which provides a standard, comparable measure for petroleum products.

This method is preferred because it directly assesses flow behavior of oil under controlled conditions and is widely standardized for aviation and other petroleum oils. A viscosity cup offers only a rough, less precise time-to-flow method and isn’t the standard for engine oils. A hydrometer measures density, not viscosity, and an infrared thermometer only reads temperature, not viscosity.