Colloids (colloidal systems) - the subtlest-suspended particles with a size range from 0.1 to MK to 1 MMK, in gas, liquid or solid. Colloidal particles less microscopic particles, but more molecules of many substances, such as water, glucose, etc. They carry electric charges of the same sign in this colloid, which explains their ability to move in an electric field (see Electrophoresis), and also stability of colloid. Liquid colloids, such as colloid solution of silver, hydrate of iron oxide and other, called the sols, a gelatinous - gel (gel gelatin, agar-agar, and so on).
If colloidal particles do not have affinity to the fluid in which they are suspended, they formed colloidal systems are liavony the colloids (sols metals sulphides, oxides and hydrates oxides); if colloidal particles interact with molecules of a liquid medium, colloids called freeze (for example, solutions of proteins, starch and other). Colloids are widely distributed in nature. Most liquids and all of dense fabric organisms are colloids. Cm. also Aerosols, Gels, Dispersed systems, Coagulation, Colloidal protection.
Radioactive colloids-see Radioactive drugs.