ABSTRACT
Colloid science is the physical chemistry of dispersions in liquids, a gas, a solid, or a liquid, present in finely divided form in a liquid. Deformable interfaces have one important factor in their favor as to the possibilities of learning something about them: the interfacial tension can be measured quite easily. This interfacial tension is the force by which a system consisting of different phases succeeds in avoiding situations in which a too great number of molecules are in energy-rich situations. A surface tension difference along a surface may arise either by a temperature difference or by a concentration gradient. The surface tension of a liquid usually decreases with increasing temperature with increasing concentration of a dissolved substance, it may either increase or decrease. The higher interfacial tension to the left will exert a larger pull on the surface than the lower-interfacial tension to the right, and a surface flow will arise which entrains some of the underlying liquid.
