Suspensions, Colloids, and Solutions
Three Different Types of Mixtures

Strictly speaking, a solution is a homogenous mixture of two or more substances in which the materials do not separate into distinct parts given time. (Realize though, that there are many types of solutions.)  For instance, once a sugar solution is made, providing evaporation doesn’t take place, the sugar and water will remain equally distributed throughout the mixture.  

That is contrast with two other mixtures that we will consider.  Suspensions are mixtures where two or more substances are unable to stay homogenously mixed for a long period of time.  Soon or later, the substances in the mixture will settle out.  Colloids or colloidal suspensions consist of substances mixed in other materials but, due to the fact that these substance are relatively speaking so large, the properties are not the same throughout the mixture.  The mixture cannot be said to be homogenous (it might look that way, but…)  However the particles are not so large so as they settle out like suspensions.  Summarizing the differences between solutions, suspensions, and colloids.

Three Kinds of Mixtures
	Suspensions	Colloids	Solutions
Made up of...	Different phases	2 different phases	solute and solvent
Properties	heterogeneous	heterogeneous	homogeneous
Size	>1000 Angstroms 1000 X 10-10m	10 Angstroms- 1000 Angstroms	1 Angstrom
Visibility of Particles	visible	Sometimes cannot be seen	not seen
Appearance	Cloudy	distributed throughout, clear to opaque	clear
Can it be filtered?	Yes	Not through ordinary means (requires small filters)	No
Settling?	Yes	No	No
Examples	Dirt in water Milk in water	Milk Mayonnaise Butter Egg Whites	Salt water Ammonia in Water