Dark regions are areas where the layer is two droplets thick, while the 4-5 larger white circular regions are vacancies. Salad dressings, milk, and hand lotion are all familiar examples of emulsions. Commonly, the continuous phase is water or another polar solvent and the dispersed phase is an oil. If no special measures are taken, the drops in the dispersed phase will revert to a separate continuous phase - a familiar behavior to those who enjoy oil and vinegar dressings. Sedimentation and creaming occur when buoyancy forces are large compared to the forces associated with Brownian motion.
Raw milk develops a layer of cream on the top which consists of large oily droplets.
Homogenized milk, on the other hand, is processed to reduce the size of these large droplets so that no creaming occurs. Typically, drops must be less than approximately 1 m m to remain suspended. However, emulsions have a great potential for use in many other areas, including high tech optical applications. For example, Fig. 2 shows an emulsion made with a nematic liquid crystal. The amount of light that each drop transmits can be varied by placing the drops in a strong electric or magnetic field.