Foams

thumb|Top of a foamy drink Foam is a two-phase material systems where a gas is dispersed in a second, non-gaseous material, specifically, in which gas cells are enclosed by a distinct liquid or solid material. Foam "may contain more or less liquid [or solid] according to circumstances", although in the case of gas-liquid foams, the gas occupies most of the volume.

material consisting of pockets of gas in a metallic matrix

thumb|right|250px|Dosage of defoamer A defoamer or an anti-foaming agent is a chemical additive that reduces and hinders the formation of foam in industrial process liquids. The terms anti-foam agent and defoamer are often used interchangeably. Strictly speaking, defoamers eliminate existing foam and anti-foamers prevent the formation of further foam. Commonly used agents are insoluble oils, polydimethylsiloxanes and other silicones, certain alcohols, stearates and glycols. The additive is used to prevent formation of foam or is added to break a foam already formed.

foam created by the agitation of seawater

foam that is used for fire suppression

viscoelastic form of open-celled polyurethane foam, used for cushions and mattresses

foam made of plastic

substance which makes it possible to form or maintain a uniform dispersion of a gaseous phase in a liquid or solid

ultra-light metallic material

composite material

thumb|Styrofoam insulation extruded polystyrene foam (XPS), owned and manufactured by DuPont Styrofoam is a brand of closed-cell extruded polystyrene foam (XPS), manufactured to provide continuous building insulation board used in walls, roofs, and foundations as thermal insulation and as a water barrier. This material is light blue in color and is owned and manufactured by DuPont. DuPont also has produced a line of green and white foam shapes for use in crafts and floral arrangements.

open celled foam used for acoustic treatment

non-lethal bomb used to seal tunnels

Fogbank (stylized as FOGBANK) is a code name given to a secret material used in the W76, W78 and W88 nuclear warheads that are part of the United States nuclear arsenal. The process to create Fogbank was lost by 2000, when it was needed for the refurbishment of old warheads. Fogbank was then reverse engineered by the National Nuclear Security Administration (NNSA), over a span of five years, and at the cost of tens of millions of dollars.

closed-cell polyethylene foam made from non-crosslinked, low-density polyethylene (LDPE) resins