What is a suspension?

In which solids are dispersed in liquids, are called suspensions. 
A suspension is a heterogeneous mixture
Particles of a suspension are visible to the naked eye.
Properties of a Suspension

      •    Suspension is a heterogeneous mixture.
      •    The particles of a suspension can be seen by the naked eye.

  • The particles of a suspension scatter a beam of light passing through it and make its path visible.

      •    The solute particles settle down when a suspension is left undisturbed, that is, a suspension is unstable.

WHAT IS A COLLOIDAL SOLUTION?

    A colloidal solution is a heterogeneous mixture, for example, milk. 
    Because of the small size of colloidal particles, we cannot see them with naked eyes.
    These particles can easily scatter a beam of visible light.
        Tyndall effect
    The scattering of a beam of light is called the Tyndall effect
    The Tyndall effect can also be observed when a fine beam of light enters a room through a small hole. 
    This happens due to the scattering of light by the particles of dust and smoke in the air.

Observation of Tyndall effect

    The Tyndall effect can be observed when sunlight passes through the canopy of a dense forest. 
Properties of a colloid.
    A colloid is a heterogeneous mixture. 
    The size of particles of a colloid is too small to be individually seen by naked eyes.
    Colloids are large enough to scatter a beam of light passing through it and make its path visible.
    They do not settle down when left undisturbed, that is, a colloid is quite stable.
    They cannot be separated from the mixture by the process of filtration. 


Dispersing medium

    The components of a colloidal solution are the dispersed phase and the dispersion medium.
    The solute – like component or the dispersed particles in a colloid form the dispersed phase, and the component in which the                dispersed phase is suspended is known as the dispersing medium.