text: One form of this quantity is equal to lambda times temperature to the three halves power divided by the temperature plus Sutherland's constant.
full_question: One form of this quantity is equal to lambda times temperature to the three halves power divided by the temperature plus Sutherland's constant. Ludwig Prandtl proposed a structure which separates regions with zero and nonzero values of this quantity called the boundary layer. This quantity is lowered due to shear stress in thixotropic compounds. The ratio of inertial forces to forces caused by this quantity defines the Reynolds number. This quantity, which comes in kinematic and dynamic forms, is constant for Newtonian fluids. For 10 points, name this quantity which is a fluid's resistance to flow.
first_sentence: One form of this quantity is equal to lambda times temperature to the three halves power divided by the temperature plus Sutherland's constant.
raw_answer: viscosity [or dynamic viscosity; or kinematic viscosity]