🔍 Key Concepts

• Viscosity tests for fuel and lube oils and how flow time through an orifice is used • Difference between gravity flow and flow caused by applied pressure in test equipment • How a heated oil bath and thermometer are used to keep a test sample at a constant temperature

💭 Think About

• Look at the central vertical chamber and bottom opening: does the arrangement suggest the oil is being pushed by pressure, or simply allowed to drain by its own weight? • Why is there a 60 c.c. mark on the beaker, and why is the sample surrounded by a heated bath with a thermometer—what property of the oil needs both a fixed temperature and a timed flow? • Compare the diagram with what you would expect for a device that measures flash point or vapor pressure—do you see any place where vapors are contained and ignited or pressurized?

✅ Before You Answer

• Identify whether any pressure source (piston, pump, or compressed air line) is shown acting on the oil sample in the diagram • Confirm that the thermometer is in the surrounding bath, indicating control of temperature during the flow test • Note that the time to collect a fixed volume (60 c.c.) of oil is the key measured variable, and match that to the choice that uses time as the indicator of the property being tested