Lucretius says…..“Observe what happens when sunbeams are admitted into a building and shed light on its shadowy places. You will see a multitude of tiny particles mingling in a multitude of ways in the empty space… They all derive the restlessness from the atoms. It originates with the atoms, which move of themselves”
Migration phenomena whereby the difference in density between the continuous and dispersed phase leads to gravitational phase separation. In the case of suspensions sedimentation occurs as the dispersed phase is denser than the continuous whereby the suspended particles join together and increase in size. Below are the two types of this phenomenon, reversibly and flocculation.
CLASSIFICATION AND PREPARATION OF COLLOIDS COLLOIS TYPE DIPERSING DISPERSED EXAMPLE MEDUIM SUBSTANCELIQUID AEROSOL LIQUID GAS FOG, HAIR SPRAY, CLOUDSOLID AEROSOL SOLID GAS SMOKE, DUST IN AIRFOAM GAS LIQUID WHIPPED CREAM, BEATEN EGGEMULSION LIQUID LIQUID WHITE, MIL, MAYONAISESOL SOLID LIQUID PAINT, STARCH MIXTURESOLID FOAM GAS SOLID MARSHMALOOWSOLID EMULSION SOLID SOILD OPAL
CLASSIFICATION AND PREPARATION OF COLLOIDS• CondensationIt is the process of making particles of atom/ion/molecular size unite to form particles of colloidal size.• DispersionIt is a process of breaking down large particles to colloidal size.
CLASSIFICATION AND PREPARATION OF COLLOIDS• Emulsifying AgentStabilizes an emulsion so that it does not separate into its component.
Tyndall Effect also known as Tyndall scattering is light scattering by particles in a colloid or particles in a fine suspension. It is named after the 19th century physicist John Tyndall. It is similar to Rayleigh scattering, in that the intensity of the scattered light depends on the fourth power of the frequency, so blue light is scattered much more strongly than red light. An example in everyday life is the blue color sometimes seen in the smoke emitted by motorcycles particularly two stroke machines where the burnt engine oil provides the particles.
BROWNIAN MOVEMENT• If a colloid is viewed in a special microscope, you will see particles moving in erratic, haphazard motion.• Brownian Movement is due to the constant bombardment of the dispersed particles by rhe dispersion medium.
ELECTROPHORESIS• A process whereby the changed protein particles migrate at varying rates to electrodes of opposite charge.
DIALYSIS and HEMODIALYSIS• DialysisProcess of separating solute particles from colloidal particles by means of a semi permeable membrane.
DIALYSIS and HEMODIALYSIS• HemodialysisA method that is used to achieve the extracorporeal removal of waste products such as Creatinine and urea and free water from the blood when the kidneys are in a state of renal failure.