Many formulated products pass through or end up as foams, comprising immiscible millimeter sized bubbles dispersed into an aqueous continuous phase. Frequently, surfactants or polymers are employed to stabilize the foam structure. Recently, similarities between the role of small solid particles in stabilizing aqueous foams and conventional surfactants in air¿water systems have been observed. Here, we wish to explore these facets, focusing on aqueous foams stabilized solely by silica particles of differing hydrophobicity. These silica foams can be remarkably stable (months), but with seemingly small changes in hydrophobicity, they can also show little or no foaming ability at all. Further, the non-foaming systems may be rendered substantially more foaming by the addition of simple salt. These observations suggest a complex and fascinating adsorption behaviour at the air-water interface.