Texas Commission on Environmental Quality (TCEQ). Class C Water License Exam

Which of the following is NOT a physical characteristic of water?

1. Taste

2. Odor

3. Viscosity

4. Temperature

The correct answer is: Viscosity

Viscosity is a measure of a fluid's resistance to flow and deformation and is often classified as a physical property of liquids; however, in the context of the question about what is NOT a physical characteristic of water specifically, it is more commonly associated with the classification of the behavior of fluids rather than a direct characteristic of pure water itself. Taste, odor, and temperature are direct characteristics experienced when encountering water. Taste refers to the flavor presence in water, which can indicate contaminants or mineral presence. Odor pertains to any smells that might be present in water, often identifying organic materials or chemicals. Temperature is a straightforward measure of how hot or cold the water is, vital in various applications like chemical reactions and ecology. While viscosity can affect how water behaves under certain conditions, it is not a characteristic that would be commonly referred to when describing water's fundamental properties in everyday contexts, thus leading to the identification of viscosity as the choice that does not directly align with the standard physical characteristics of water.