Surface and Colloid Chemistry is the branch of chemistry that investigates the physical and chemical phenomena occurring at interfaces—the boundaries between different phases like solid-liquid or liquid-gas. It explores key processes such as adsorption, surface tension, and heterogeneous catalysis, which are critically important in the study of colloids—mixtures like milk, fog, and paint, where one substance of microscopically dispersed particles is suspended throughout another. Because the properties of these systems are dominated by their vast interfacial area, this interdisciplinary field is fundamental to numerous practical applications, including the formulation of detergents, pharmaceuticals, and food products, as well as processes in environmental remediation and materials science.