Bubbles and Foams

Bubbles are produced in the ocean by the action of wind and waves. Whitecaps, which cover on average 3% of the ocean surface, consist of a dense raft of bubbles with a size spectrum centred on about 200 jum diameter ranging from perhaps 50 up to 1 mm or two (Blanchard, 1963). The surface of a bubble is also a miniature air/sea interface analogous to the sea surface proper. Not only will the chemistry of bubbles be similar, therefore, to that of surface films, but it seems very plausible that surfactants picked up by the surfaces of rising bubbles will be transported to the surface and be 

Similar differences in the surfactant nature of soluble and insoluble species can be found in studies of foam stability. Broadly speaking, insoluble or solid-type surfactants do not efficiently stabilise foams (Garrett, 1967b). On the other hand, water-soluble surfactants such as the alkyl sulphonates, phosphates and tri-alkyl ammonium salts, all common detergents, form prolific foams. Wilson (1959) noted the accumulation of albuminoid-N compoimds in coastal sea foams, while Southward (1953), who found a variety of planktonic and benthic oi anisms in such foams, concluded that proteins were probably responsible for the foam stability. Wilson and Collier (1972) have observed the production of such foam-stabilising events in appreciable quantities by various marine organisms such as diatoms. 

The process begins with an air bubble inside the liquid phase. At the surface, the bubble detaches and moves up under gravity. The detergent molecule forms a bilayer in the bubble film. The water in between is the same as the bulk solution. This may be depicted as follows a surface layer of detergent is applied, a bubble forms with air and a layer of detergent, and the bubble at the surface forms a double layer of detergent with some water in between TLF varying from 10 pm to 100 pm). 

The bubble test of shaking a water solution, although simple, is very sensitive and may be used to determine the presence of very minute (around parts per million) contents of surface-active substances. 

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These coatings bubble and foam to form a thermal insulation when subjected to a fire. They have been used for many decades. Such coatings cannot be differentiated from conventional coatings prior to the occurrence of a fire situation. Thereupon, however, they decompose to form a thick, nonflammable, multicellular, insulative barrier over the surface on which they are applied. This insulative foam is a very effective insulation that maintains the temperature of a flammable or heat distortable substrate below its ignition or distortion point. It also restricts the flow of air (oxygen) to fuel the substrate. 

Separation Techniques, Academic, New York, 1972 Lemhch, Adsub-ble Methods, in li (ed.). Recent Developments in Separation Science, vol. 1, CRC Press, Cleveland, 1972, chap. 5 Grieves, Chem. Eng. J., 9, 93 (1975) Valdes-Krieg King, and Sephton, Sep. Purif Methods, 6,221 (1977) Clarke and Wilson, Foam Flotation, Marcel Deldcer, New York, 1983 and Wilson and Clarke, Bubble and Foam Separations in Waste Treatment, in Rousseau (ed.). Handbook of Separation Processes, Wiley, New York, 1987. 

It is common observation that a liquid takes the shape of a container that surrounds or contains it. However, it is also found that, in many cases, there are other subtle properties that arise at the interface of liquids. The most common behavior is bubble and foam formation. Another phenomena is that, when a glass capillary tube is dipped in water, the fluid rises to a given height. It is observed that the narrower the tube, the higher the water rises. The role of liquids and liquid surfaces is important in many everyday natural processes (e.g., oceans, lakes, rivers, raindrops, etc.). Therefore, in these systems, one will expect the surface forces to be important, considering that the oceans cover some 75% of the surface of the earth. Accordingly, there is a need to study surface tension and its effect on surface phenomena in these different systems. This means that the structures of molecules in the bulk phase need to be considered in comparison to those at the surface. 

Transfer of gas from a rising bubble into a liquid is becoming increasingly important bubble and foam columns are often more efficient than... 

Jordan, A.D., Napper, D.H. (1994). Some aspect of the physical chemistry of bubble and foam phenomena in sparkling wine. Sixth Australian Wine Industry Conference, 237-246. 

D.O. Harper, Bubble and Foam Fractionation, PhD Thesis, University of Cincinnati, Cincinnati, OH 1967. 

When you mix baking soda and vinegar, a vigorous chemical reaction occurs. The mixture bubbles and foams up inside the container, as you can see in Figure 3. 

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