Surface Tension

Abstract

OUR subject is very closely associated with the comprehensive topic of cohesion, a topic which attempts an answer—not to the problem, why we are here to-night, which is a matter for the theologians to discuss—but the problem, how we are here, in our present habits, and not as a chance medley of unattracting atoms. To attempt to answer such a query takes us very far towards the fundamentals of atomic structure and behaviour, but the problem, as we envisage it in the light of to-day's theories, still bears a strong resemblance to the problem as it was posed, and answered, by van der Waals. How comes it that, if material particles attract each other, the whole structure of the universe does not collapse under these attractions? We can formulate an answer to the question if we take into account the thermal motions of the particles. “In nature it is cohesion between atoms which tends to produce condensation and solidification, and temperature which tends to produce dissociation. … Temperature is a manifestation of kinetic energy and cohesion of potential energy and the interplay of these two forms of energy is responsible for many of the observed physical properties of matter”(Lennard-Jones). Cohesion and temperature—these, then, are the protagonists who play out the drama.