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.
Definition of viscosity. plural. viscosities. 1 : the quality or state of being viscous. 2 : the property of resistance to flow in a fluid or semifluid. 3 : the ratio of the tangential frictional force per unit area to the velocity gradient perpendicular to the direction of flow of a liquid âcalled also coefficient of viscosity.