What does viscosity measure in fluids?

• A. The ability to flow
• B. The capacity to expand
• C. The resistance to flow
• D. The temperature influence

Answer: (C)

Viscosity measures a fluid's resistance to flow. It quantifies how thick or thin a fluid is and describes the internal friction that exists within the fluid. A higher viscosity indicates that a fluid will resist motion more than a fluid with lower viscosity. For example, honey has a higher viscosity compared to water, meaning it flows more slowly. Understanding viscosity is crucial in various applications, especially in construction and paving, where the flow properties of materials can significantly impact workability and performance.

The other choices focus on different characteristics; while aid in describing fluids, they do not define viscosity directly. The ability to flow pertains to fluid dynamics but does not encapsulate the concept of resistance that viscosity emphasizes. The capacity to expand relates to changes in volume with temperature or pressure, and temperature influence looks at how temperature affects the state of a fluid but does not directly relate to its definition of viscosity.