Lyophobic colloids are not formed by simple mixing of dispersed phase and dispersion medium. Their colloidal sols can be prepared only by special methods. Emulsion are colloids of liquid dispersed phase and liquid dispersion medium. Micelles formation occurs when temperature is above a particular temperature called Kraft temperature Tκ and concentration above a particular value know as critical micelle concentration (CMC). Tyndall effect can be observed when the refractive indices of the dispersed phase and the dispersion medium differ greatly in magnitude.