Example:

Let us take the case of salt being dissolved in water at 25°C. The maximum amount of salt that can be dissolved in 100 g of water is 35.7 g. This is the solubility of salt at 25°C. If 15.0 g of salt readily dissolve when added to 100 g of water, the salt solution does not contain the maximum amount of solute. The solution is therefore unsaturated.

Salt can still be dissolved when added to the unsaturated solution, but there will be a point wherein the salt can no longer be dissolved. At that point, water has dissolved the maximum amount of salt that it can hold at 25°C. Such solution is now saturated.

Meanwhile, a supersaturated solution is prepared by setting a saturated solution at a higher temperature. Usually, the undissolved solutes are filtered out and, if undissolved solutes remain after cooling, then the solution is said to be supersaturated.

Such a solution, however, is unstable. When a tiny “seed” of the solute is introduced into the solution, the dissolved solute will come out of the solution as pure crystals.