õlivesi

Õlivesi (Estonian for "oil water") is a term used to describe systems made of oil and water, either as distinct phases or as emulsions in which one liquid is dispersed as droplets within the other. Oil and water are largely immiscible due to differences in polarity and intermolecular forces; in ordinary conditions, oil tends to form a separate layer above water because it is usually less dense.

An emulsion occurs when droplets of one liquid are dispersed in the other with energy input, such as shaking or homogenization, and often with an emulsifier or surfactant to stabilize the droplets. There are two main types: oil-in-water (O/W) emulsions, where oil droplets are suspended in water (examples include milk and many dressings); and water-in-oil (W/O) emulsions, where water droplets are suspended in oil (examples include butter and certain creams). Emulsions can be stabilized by natural emulsifiers such as proteins and phospholipids, or by synthetic surfactants.

Stability is typically limited: without sufficient emulsification, droplets will coalesce and the system will separate over time. Factors such as temperature, shear, and the presence of emulsifiers influence the longevity of an õlivesi emulsion.

In practice, õlivesi is discussed in food science, cosmetics, and environmental contexts. In cooking, emulsions are used to create sauces and dressings; in environmental science, oil-water mixtures are central to discussions of oil spills and their remediation.

See also: emulsion, immiscible liquids, surfactant, phase separation.