Difference between Solutions, Suspensions, and Colloids

Solution is a mixture of two or more substances in a single phase. At least two substances must be mixed in order to have a solution. The substance in the smallest amount and the one that dissolves or disperses is called the solute. The substance in the larger amount is called the solvent. In most common instances water is the solvent. The gases, liquids, or solids dissolved in water are the solutes.

Dissolving of sugar in water is an example of a solution because
it completely dissolves in water, therefore it is an aqueous
solution. In this case the sugar is the solute, and water is the solvent.

Suspension is a heterogeneous mixture of larger particles. These particles are visible and will settle out on standing. 

The ocean is an example of a suspension because the sand
settles out when mixed with water. The separation is visible
to the human eye, making it easier to separate the mixture.
eye

...HOW EVER... 


Colloid is a homogenous mixture of intermediate size particles. The particles  particles of one substance dispersed through a second substance. the particles do not settle and cannot be separated out by ordinary filtering or centrifuging like those in a suspension.

Milk is a colloid because to the human eye it looks like a
solution, however there are different substances in Milk.
When seperated properly, or when a light it shone through
it you can see the different substances. Even though
they can't been, seen they are still there, thus making milk
a colloid.