🔍 Key Concepts

• Viscosity as the "thickness" or internal resistance to flow of a liquid • How temperature typically affects the thickness of lubricating oil • Real-world examples (e.g., engine oil on a cold day vs. a hot day)

💭 Think About

• Think about what happens to lubricating oil when an engine first starts on a very cold morning compared to after it has warmed up. • Ask yourself: does the oil become easier or harder to pour as it gets hotter? • Consider whether viscosity is a definition (what it is) or a behavior (how it changes) in the different answer choices.

✅ Before You Answer

• Make sure you understand that viscosity is related to how easily a fluid flows. • Check which options correctly describe how temperature changes affect viscosity (thicker vs. thinner). • Eliminate any choice that suggests viscosity is unrelated to temperature, based on your real-world experience with oils and fuels.