Q.Internet my friend

1. Brownian motion
2. Collect information about Surface Chemistry.
3. Collect information about Adsorption.
4. Collect information about Brownian Motion

Colloidal dispersions show several characteristic properties. The Tyndall effect is the scattering of light by colloidal particles, which makes the path of a light beam through the dispersion visible (as a bright 'Tyndall cone') to an observer at right angles, unlike a true solution, through which light passes without a visible path; it requires the particle diameter to be comparable to the light's wavelength and a large difference in refractive index between the phases, and is used to estimate particle size/number and to distinguish colloids from true solutions. Colour depends on the wavelength scattered, the viewing angle (scattered vs transmitted light), and particle size (e.g. fine gold sol is red, coarser gold sol is purple). Brownian motion is the ceaseless, random zig-zag movement of colloidal particles, first observed by Robert Brown and explained by Einstein in 1905, caused by constant random collisions with the fast-moving molecules of the dispersion medium, which transfer kinetic energy to the particles and keep them in perpetual erratic motion.