A colloid is a substance that appears to be a singular component but is actually made up of two different components. Milk is colloid made up of butter fat and water.
A colloid is a substance mixture. One component of a colloid is able to disperse throughout the other component. This dispersion is invisible by an optical microscope but can be seen with an electron microscope. Under an electron microscope the component clumps can be seen. The clumps have a murky appearance. The two components of a colloid are referred to as the colloid particle and dispersing mechanism. In milk the colloid particle is the butter fat. The dispersing material in milk is water. Any solid, liquid or gas combination has the possibility of forming a colloid. If the particle is able to interact with another environment, it has the possibility of becoming a component in a colloid. The exception being a two-gas colloid because gases are miscible. A hydrocolloid is a colloid in which the colloid particles are hydrophilic polymers dispersed in water. Hydrocolloids are reversible or irreversible. Agar is a reversible hydrocolloid that exists in either a gel or solid state and can switch back and forth between the two states.