This dissertation studies the transport dynamics of a water soluble nonionic surfactant C14E6 at the air/water interface at concentration below the critical micelle concentration (CMC) and above the CMC. A method which involves using the pendant bubble as a monolayer film balance is used to directly measure the surface tension as a function of surface concentration. The equilibrium parameters could be uniquely determined by fitting the directly measured equation of state and adsorption isotherm. Instead remarkably different equilibrium parameters for the same surfactant system fit...