why do colloidal solutions differ in colours?

Solutions are a homogeneous mixture of dissolved solute particles in a solvent. Everything is dissolved. A characteristic of solutions is that if a beam of light was passed through it, it would come out the other side completely the same. This is known as the Tyndall Effect.
Colloids are a dispersion of particles of one substance through a dispersing medium made of another substance. Mayonnaise is an example of a colloid. If a beam of light is passed through a colloid, it will be scattered and dispersed in different directions. The wavelength of the light may change too, causing a different color to appear.