Emulsions have a cloudy appearance due to many phase interfaces scattering light passing through the emulsions.

Emulsions indeed exhibit a cloudy appearance primarily because the dispersed droplets scatter light. This scattering occurs at the numerous interfaces between the different phases—typically oil and water—resulting in the characteristic opacity of emulsions. The size of the droplets and the concentration of the dispersed phase play significant roles in this scattering effect.

When light passes through an emulsion, it interacts with the droplets, causing some of the light to be reflected, refracted, or absorbed. This interaction leads to the phenomenon of turbidity, which is why emulsified substances, such as mayonnaise or milk, do not appear clear.

In summary, the cloudy appearance of emulsions is a result of light scattering at the numerous phase interfaces formed by the dispersed droplets within the continuous phase.