Stabilizing Foam

Technically speaking, a foam is a dispersion of bubbles of some type of gas in a liquid. In principle, it is possible to create a foam from just about any liquid, but in most cases the newly formed bubbles burst very rapidly. Generally speaking, it is therefore necessary to stabilize the surfaces of the bubbles in the same way as soap bubbles are stabilized: by reducing the surface tension between the water and the air. The bubbles in a foam are usually large, about 1 millimeter in size, whereas the walls between the bubbles are extremely thin, on the order of micrometers.