Milk is a colloidal solution that appears to be homogeneous but actually is heterogeneous.
A colloid is typically a two-phase system consisting of a continuous phase (the dispersion medium) and a dispersed phase (the particles or emulsion droplets). The particle size of the dispersed phase typically ranges from 1 nanometre to 1 micrometre. Some examples include whipped cream, mayonnaise, milk, butter, gelatin, jelly, muddy water, plaster, coloured glass, and paper.
Based on the Nature of Interaction Between Dispersed Phase and Dispersion Medium
- Hydrophilic colloids: These are water-loving colloids. Examples include Agar, gelatin, pectin, etc.
- Hydrophobic colloids: These are the opposite in nature of hydrophilic colloids and are also called irreversible sols. Examples include Gold sols, clay particles, etc.