Convection cell

In fluid dynamics, a convection cell is the phenomenon that occurs when density differences exist within a body of liquid or gas.

Fluid properties can also be observed in gases and even in particulate solids (such as sand, gravel, and larger objects during rock slides).

If enough instability is present in the atmosphere, this process will continue long enough for cumulonimbus clouds to form, which support lightning and thunder.

Generally, thunderstorms require three conditions to form: moisture, an unstable air mass, and a lifting force (heat).

[8] Heating caused by the compression of descending air is responsible for such winter phenomena as the chinook (as it is known in western North America) or the Föhn (in the Alps).

The Sun's photosphere is composed of convection cells called granules, which are rising columns of superheated (5,800 °C) plasma averaging about 1,000 kilometres in diameter.

Altocumulus cloud as seen from the Space Shuttle. Altocumulus clouds are formed by convective activity.
6-gallon bucket of honey wine after fermenting 10 days with cinnamon floating on top. Convection is caused by yeast releasing CO2.
Stages of a thunderstorm's life.
Movie of the solar photosphere observed with the Swedish 1-m Solar Telescope (SST) on La Palma, Spain. The movie shows solar granulation which is a result of convective motions of bubbles of hot gas that rise from the solar interior. When these bubbles reach the surface, the gas cools and flows down again in the darker lanes between the bright cells. In these so-called intergranular lanes, we can also see small bright points and more extended bright elongated structures. These are regions with strong magnetic fields.