What are sols?

 A colloidal system in which solid  particles are dispersed in a liquid is referred to as a sol, to distinguish it from a true solution. In a true solution, the substances separate into molecules and ions that disperse homogenously throughout the volume of the solvent. But when a protein such as gelatin is dispersed in water, the solution-like mixture that results is a sol. Examined under a microscope, the individual protein particles are large enough to be distinguished from the dispersion medium.