A colloid is a type of mixture that contains particles ranging between 1 and 1000 nanometers in diameter, yet are still able to remain evenly distributed throughout the solution/Physical_Properties_of_Matter/Solutions_and_Mixtures/Colloid). Colloids are mixtures in which one or more substances are dispersed as relatively large solid particles or liquid droplets throughout a solid, liquid, or gaseous medium. The particles of a colloid remain dispersed and do not settle due to gravity, and they are often electrically charged. To be classified as a colloid, the substance in the dispersed phase must be larger than the size of a molecule but smaller than what can be seen with the naked eye/Physical_Properties_of_Matter/Solutions_and_Mixtures/Colloid). Colloids can be classified based on the phase of the dispersed substance and what phase it is dispersed in. The types of colloids include sol, emulsion, foam, and aerosol/Physical_Properties_of_Matter/Solutions_and_Mixtures/Colloid). Some examples of colloids include milk, cream, mayonnaise, smoke, dust, some inks, paints, and clouds. Colloids exhibit properties intermediate between those of suspensions and solutions, and the particles in a colloid are larger than most simple molecules, but small enough that they do not settle out upon standing.