🔍 Key Concepts

• Penetration test for grease in lubrication engineering • How time and depth are used in standardized tests (ASTM cone penetration) • Difference between a measured quantity (depth) and a test condition (time or temperature)

💭 Think About

• Ask yourself: in a standard cone penetration test, what is actually RECORDED as the test result—time, temperature, or depth? • Look at the answer choices and separate what sounds like a test condition (something you set) versus the measured outcome (something you read). • Which option describes a value that can be given a "penetration number" on a continuous scale (e.g., softer vs harder grease)?

✅ Before You Answer

• Identify which choices talk about time or temperature as conditions rather than the measurement itself. • Verify that penetration tests are typically run for a fixed time interval, not a variable one. • Confirm that the penetration number refers to the extent of cone penetration, not when the cone STARTS to penetrate.