Contact angle 0 When the interface is in intimate contact with the walls of a container,for example a capillary tube, the interface intersects the solid surface at an angle,0,which is a function of the relative adhesive tension of the liquids to the solid.Contact angle θ When the interface is in intimate contact with the walls of a container, for example a capillary tube, the interface intersects the solid surface at an angle, θ, which is a function of the relative adhesive tension of the liquids to the solid