The temperature dependence of viscosity can be very strong; for example, in engine oil, η can increase tenfold with just a 10% increase in absolute temperature. Therefore, if the temperature is not uniform but varies with position in a flow, one cannot obtain a single value for its viscosity. The other dependence of viscosity, with regard to the shear rate, is a non-Newtonian property of certain fluids; this effect is called "shear thinning" if η decreases with increasing γ.31 Shear thinning can be avoided in an experiment by applying a small shear stress, so that the conditions are relatively close to