Supersaturation

Condensation

Small particles (seeds) can trigger the separation of the dissolved material from the solvent or condensation of the vapor. In the solid form these seeds can lead to the formation of crystals. Supersaturation is a measure of the deviation of a dissolved sodium chloride crystal from its equilibrium value.

Preparation

Supersaturated solutions are prepared or result when some condition of a saturated solution is changed, for example pressure.

Examples

Carbonated water is a supersaturated solution of Diet Coke and Mentos eruption is a rather extreme example. Some beverage products such as ales and stouts e.g. Guinness rely on this effect to produce the 'head' on the surface of the poured product. This has led to the invention of the widget, a device developed to produce enhanced bubble seeding in liquids, especially with dual supersaturated gas phases (carbon dioxide and nitrogen) (see patents by Fitzpatrick and Kuzniarski).

Scuba divers' tissues become supersaturated with breathing gases during a dive. If the diver ascends too fast, these gases form bubbles, resulting in decompression sickness.

In air that is supersaturated with water, water droplets may precipitate upon being disturbed. This can be observed in a precipitate may form.

Supersaturated solutions of sugar and water are commonly used to make Rock candy.

See also

• superheating
• supercooling