To compare the extent to which different solids will dissolve in water at the same temperature.
Pour equal volumes of distilled water in separate beakers. To the first add powdered glass, to the second add common salt, to the third add slaked lime. In each case continue to add until the solution is saturated, i.e. until excess solid settles at the bottom of the beaker. Filter each solution into an evaporating basin and evaporate to dryness over a sand bath. Compare the residues.
You will notice that the solution of glass leaves little or no residue, the solution of slaked lime leaves traces or 'rings' of lime, and the solution of salt leaves a quantity of solid residue.
From the amount of residue obtained after evaporation, we may conclude that different substances do not dissolve to the same extent in the same solvent. The experiment above shows that glass is almost insoluble in water, slaked lime dissolves to some extent, and salt dissolves to a greater extent.