Foam
form of matter containing pockets of gas in a solid or liquid
Foam is a two-phase material system and a type of dispersed media, consisting of gas cells dispersed in a continuous liquid or solid phase to form a cellular structure. In most foams, the gas occupies most of the volume and is divided into bubbles separated by thin films of liquid or solid material.
The formation, stability and properties of foams are studied in physics, physical chemistry and materials science. Foams are classified as liquid or solid foams, which differ in their formation, structure and physical behaviour. Solid foams may be further divided into open-cell and closed-cell structures that differ in their mechanical and transport properties.
Foams are formed by dispersing gas into a liquid or solid, typically in the presence of surfactants or other stabilising agents, and their stability depends on factors such as surface tension, the Marangoni effect, drainage, and gas diffusion.
Foams have numerous applications, including thermal insulation, packaging, flotation devices, sandwich-structured composite materials, fire retardant foams, froth flotation, foam fractionation, and filtration. Common examples are soap foam, the head on beer, bread, bath sponges, and polymer foams.
Etymology
The word derives from Old English fām, from Proto-Germanic faimaz, ultimately related to Sanskrit phéna.
Structure
One scale is the bubble: material foams are typically disordered and have a variety of bubble sizes.
“Foam” enters the record as form of matter containing pockets of gas in a solid or liquid. Crown Archives preserves that source wording while asking what Foam, form and matter can confirm, complicate or overturn.
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“Foam” is worth following because a concise public description often conceals a longer documentary argument. Here, Foam, form and matter provides the most credible route into that argument.
Vocabulary and entity names are the principal evidence signals here, because they determine the precision of every later search. The source revision retrieved here is dated Sep 7, 2026. The linked authority identifier is Q215414. None of the 0 selected statements returned an explicit reference.
The absence of detail may reflect summary conventions rather than a lack of surviving documentation. The source lead contains qualifying language; that uncertainty should survive quotation, summary and reuse. Authority statements aid reconciliation but still require their own references, qualifiers and ranks to be checked.
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This entry incorporates text from “Foam” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.