# How can I make a supersaturated solution crystallize?

Or simply scratch the sides of the flask, The added crystal, or the scratch, serves as a so-called $\text{site of nucleation}$. A crystalline mass deposits. Note that the $\text{supersaturation}$ defines a metastable, non-equilibrium condition. And the crystals that result from precipitation of a supersaturated solution are usually not first-class...