The Science of Living Things series demonstrates that Bobbie Kalman and her staff have turned out yet another informative and finely produced series of books. . . . this whole series would make a welcome addition to the elementary school library -- Kay Lehr, Fort Rouge School, Manitoba, Jan. 1999.
perpendicularity - the quality of being at right angles to a given line or plane (especially the plane of the horizon) oblongness, rectangularity - the property of being shaped like a rectangle.
Viscosity of a fluid is a measure of its resistance to gradual deformation by shear stress or tensile stress. The shear resistance in a fluid is caused by inter molecular friction exerted when layers of fluid attempt to slide by one another. viscosity is the measure of a fluid's resistance to flow.