(1) Concentration of ores in metallurgy : Some oils (such as pine oil) are used in the froth floatation process for the concentration of sulphide ores of metals. Oil forms emulsion with ore particles. Air is bubbled through emulsion to raise it to the surface and skim it off. (2) In medicine : Water in oil emulsions are used in several pharmaceuticals and cosmetics that are available in liquid form. Examples include cod-liver oil, B-complex, ointments etc. (3) Cleansing action of soaps : Oil in water emulsion is the basis for the cleansing action of soaps. (4) Milk : Milk is an emulsion of fat in water. It is an important constituent in our diet.