Stable and unstable stratification

Buoyancy forces tend to preserve stable stratification; the higher layers float on the lower ones.

This often causes mixing at the interface, creating new diffusive layers (see photo of coffee and milk).

Sometimes, two physical properties diffuse between layers simultaneously; salt and temperature, for instance.

Temperature inversions are a weather event which happens whenever an area of the lower atmosphere becomes stably-stratified and thus stops moving.

The deep ocean waters slowly warm and freshen through internal mixing (a form of double diffusion[4]), and then rise back to the surface.

Stratification can strongly affect the mixing of fluids,[5] which is important in many manufacturing processes.

Typical mixing pattern for many lakes, caused by the fact that water is less dense at the freezing point than at 4 Celsius. Lake stratification is stable in summer and winter, becoming unstable in spring and fall when the surface waters cross the 4 Celsius mark.
Earth's lithosphere includes upwards heat flow , partial convection, and a metal-layer core .
Vertical temperature gradient cause by stable stratification of air inside a room. Note hot air rising convectively from the person; bodyheat temporarily disrupts the stable stratification.