Kapillarhöhe

Kapillarhöhe refers to the height that a liquid rises or falls in a narrow tube due to capillary action. This phenomenon is a result of the interplay between adhesive forces between the liquid and the tube walls, and cohesive forces within the liquid itself. When adhesive forces are stronger than cohesive forces, the liquid wets the surface of the tube and climbs upwards, resulting in a positive capillary height. Conversely, if cohesive forces are stronger, the liquid does not wet the surface, and the liquid level inside the tube will be lower than the surrounding liquid, leading to a negative capillary height.

The extent of capillary action is inversely proportional to the radius of the tube. Narrower tubes exhibit a greater capillary height. This relationship is described by the Jurin's law, which states that the capillary rise is directly proportional to the surface tension of the liquid and inversely proportional to the radius of the tube and the density of the liquid. Kapillarhöhe is a critical factor in various natural and industrial processes, including the transport of water in plants, the wicking of liquids in porous materials, and the operation of certain types of scientific instruments. Understanding this concept is essential in fields such as fluid mechanics, material science, and biology.