Question

Describe the following term while stating the property of colloid:

Brownian movement

Answer 1

Brownian movement is the continuous, random zig-zag motion of colloidal particles in a dispersion medium. It was discovered by botanist Robert Brown in 1827 when he observed pollen grains suspended in water moving unpredictably. This movement occurs due to unequal bombardments by the molecules of the dispersion medium on colloidal particles. As these molecules collide from all sides with varying intensity, the net force causes the particles to move irregularly. Brownian movement decreases with increasing particle size and is not observed in larger suspensions. An important property of colloids, Brownian motion prevents colloidal particles from settling under gravity, thereby imparting stability to the colloidal system (sol).