| Solutions | Suspensions | Colloids | |
|---|---|---|---|
| Appearance | Clear, transparent and homogeneous | Cloudy, heterogeneous, at least two substances visible | Cloudy but uniform and homogeneous |
| Particle Size | molecule in size | larger than 10,000 Angstroms | 10-1000 Angstroms |
| Effect of Light (Tyndall Effect) | none -- light passes through, particles do not reflect light | variable | light is dispersed by colloidal particles |
| Effect of Sedimentation | none | particles will eventually settle out |
none |
==>> For more on Mixtures (Solutions, Suspensions, Emulsions, Colloids )
In summary:
A solution is always transparent, light passes through with no scattering from solute particles which are molecule in size. The solution is homogeneous and does not settle out. A solution cannot be filtered but can be separated using the process of distillation.
A suspension is cloudy and heterogeneous. The particles are larger than 10,000 Angstroms which allows them to be filtered. If a suspension is allowed to stand the particles will separate out.
A colloid is intermediate between a solution and a suspension. While a suspension will separate out a colloid will not. Colloids can be distinguished from solutions using the Tyndall effect. Light passing through a colloidal dispersion, such as smoky or foggy air, will be reflected by the larger particles and the light beam will be visible. A hydrocolloid can simply be defined as a substance that forms a gel when it comes in contact with water. Such substances include both polysaccharides and proteins .