The hiding-exposure effect is used to explain why transport is independent of this quantity under some conditions, a condition called equal mobility. The spread of the distribution of this quantity is given by the inclusive graphic standard deviation. This quantity and velocity are the axes of the Hjulstrom diagram. The particle Reynolds number is critical shear velocity times this quantity divided by kinematic viscosity. The negative base two logarithm of this quantity defines (*) phi on the Krumbein scale, which is a logarithmic version of the Wentworth scale. The components of glacial drift are organized into layers based on their values for this (10[1])quantity, and are therefore sorted, in contrast to glacial till. This quantity increases along the sequence: clay, silt, sand. (10[1])For 10 points, name this quantity of sediment that can be measured by passing it through progressively finer sieves. ■END■