Solution
A solution is a homogeneous mixture in which the particles are individual molecules or ions distributed evenly throughout the surrounding fluid. Sizes of these particles are between 0.1-1nm. Therefore, these particles cannot be seen by the naked eye, ordinary microscope, and electron microscope. These particles can pass through ordinary and ultra filter papers. A solution is unable to scatter light.
Colloids
In winter you often observe fog. Fog consists of finely divided droplets of water suspended in air. Fog scatter light from the headlights of an automobile. You might have observed that sunlight shining through a window is scattered by the dust particles. Fog and dust particles suspended in air are colloids, colloids differ from solution in scattering light while solutions cannot scatter light.
A heterogeneous mixture of tiny particles of a substance dispersed through a medium is called a colloid.
Apparently, a colloid looks homogenous like solutions. In a colloid dispersed phase is like solute in solutions and dispersion medium is like solvent in the solution.
Suspension
Such a heterogeneous mixture containing particles large enough to be seen with naked eye and clearly distinct from the surrounding fluid is called suspension. Particles of suspension are larger than that of colloids and because of large size particles they can scatter light.
Tyndall Effect
The scattering of visible light by Colloidal particles is called Tyndall effect. This phenomenon was discovered by Physicist John Tyndall in 19th century.
