B-NARD's INSTABILITY
| Collection | International Encyclopedia of Systems and Cybernetics |
|---|---|
| Year | 2004 |
| Vol. (num.) | 2(1) |
| ID | ◀ 279 ▶ |
| Object type | Discipline oriented, Methodology or model |
A phenomenon of structuration of forms through energy dissipation.
This phenomenon was discovered by the French physicist BÉNARD at the beginning of the 20th century, but its general systemic meaning was not understood until PRIGOGINE's discoveries in thermodynamics of far from equilibrium systems.
F. DAVID PEAT describes this kind of instability as follows: “It occurs when a pan of water is heated on a stove or when hot air in the desert lifts tiny particles of sand into the air. If the pan of water is heated slowly, heat at first moves upward into the cooler water by conduction. Since no part of the liquid is far from thermal equilibrium, the surface is smooth and undisturbed. However, as the water at the bottom becomes hotter, and therefore less dense, it tries to rise while, at the same time, cooler water falls from the top. Under these competing flows the water is now far from equilibrium and it contains a mixture of flows, eddies and whorls… In fact, chaos has set in.
- “As the rate of heating continues to rise, however, a critical point is reached at which the whole system moves from disorder to order. This occurs when heat can no longer be dispersed fast enough through random movements alone and the tiny ebbies suddenly become magnified into large-scale flows. Almost magically, movement in the liquid shifts from chance into a series of stable convection currents which have the effect of producing a regularly ordered lattice of hexagonal currents.
- “… millions upon millions of molecules suddenly move coherently rather than in a random way — a phenomenon that recalls the convergent movements of cells in the slime mold (Note: see Dictyostelium discoideum) or electrons in plasma.” (1988, p.78-9)
See also
Hexagonal space filling, Structure (Dissipative)