Colloids as Big Atoms

Under the right circumstances, colloidal particles can exhibit the same behavior as atoms or molecules. In his Perspective, Poon discusses the report in the same issue by Aarts et al. on their studies of colloid-polymer mixtures that simulate the interface between a liquid and a vapor. Thermal energy naturally excites capillary waves at the interface, and the experimental colloid-polymer system provides a novel way to study these excitations. The use of a colloid means that phenomena too small to be directly observed in conventional systems can be seen with an optical microscope, thus offering a new route to studying interfacial dynamics.