BROWNIAN MOVEMENT

 BROWNIAN MOVEMENT:

                                                 -Brownian motion is the random motion of a particle as a result of collisions with surrounding gaseous molecules

-Discovered by botanist Robert Brown in 1827

-Motion of particles can be usually observed by high power ultramicroscope

-Note

        doesn't depend upon the nature of the colloids but depends upon the size of the colloids

Cause :

         -The size of the particles is inversely proportional to the speed of the motion

          -This is because the transfer of momentum is inversely proportional to the mass of the particles. Lighter particles obtain greater speeds from collisions.

            -Molecules of dispersion medium due to the kinetic energy they strike against the colloidal particle (D.P). From all sides with different forces, the resultant force causes them to move 

 VISCOSITY :

                     Viscosity is a quantity that expresses the magnitude of the internal friction in a liquid. It is the measure of the fluid’s resistance to flow.

        

                  -The speed of the Brownian motion is inversely proportional to the viscosity of the fluid. The lower the viscosity of the fluid, the faster the Brownian movement.

EFFECTS:

                  The kinetic theory of gases which explains the pressure, temperature and volume of gases is based on the Brownian motion model of particles.

                    -This prevents particles from settling down, leading to the stability of colloidal solutions.

Makes the Colloid to be stable irrespective of the gravity

 Next-Viscosity