Emulsions are an important class of the colloidal system. It is a liquid-liquid colloidal system in which the dispersed phase and dispersion medium are liquids. Emulsions are a mixture of two or more immiscible liquids that are normally immiscible. They have the property to scatter the light passed through them, called Tyndall effect. If the emulsion scatters all light equally, it becomes white. If the emulsion is dilute, the low wavelength light will be scattered more and it becomes bluer and if it is more concentrated, the longer wavelength light will be more scattered and emulsion becomes more yellow.
This video explains how to study the effectiveness of different common oils (castor oil, cotton seed oil, coconut oil, kerosene oil, mustard oil) in forming emulsions.