How are supersaturated solutions prepared?
Supersaturated solutions are generally prepared by dissolving your compound in heated water.
If you add sugar, for example, to water at 25 degrees Celsius, about 210 grams of sugar will dissolve per 100 mL of water.
However, if you heat the water up to 80 degrees Celsius, the same amount of water will now dissolve 360 grams of sugar.
To make a supersaturated solution, make a saturated solution of sugar by adding 360 grams of sugar to 100 mL of water at 80 degrees Celsius. When the water cools back down to 25 degrees, that 360 grams of sugar will still be dissolved even though the water should only dissolve 210 grams of sugar. Any situation where more solute is dissolved than possible is called supersaturation.