My problem was to find out how to test or measure . I think the reason of some of the force in is cohesion and gravity. is the condition existing at the free surface of a liquid, resembling the properties of an elastic skin under tension. The tension is the result of intermolecular forces exerting an unbalanced inward pull on the individual surface molecules; this is reflected in the considerable curvature at those edges where the liquid is in contact with the wall of a vessel. Because of this property, certain insects can stand on the surfa ....