Kapillaariputkia

Kapillaariputkia, or capillary tubes, are very narrow tubes, typically made of glass or plastic, with an internal diameter of less than one millimeter. The narrowness of these tubes is key to their function, as it allows for phenomena related to surface tension and adhesion to become significant. When a capillary tube is placed in a liquid, the liquid can either rise or be depressed within the tube. This effect, known as capillary action or capillarity, is a result of the cohesive forces between liquid molecules and adhesive forces between the liquid and the tube walls. If the adhesive forces are stronger than the cohesive forces, the liquid will wet the tube and rise. Conversely, if cohesive forces are dominant, the liquid will be depressed. The height to which a liquid rises in a capillary tube is inversely proportional to the diameter of the tube and directly proportional to the surface tension of the liquid and the density of the liquid. This principle is utilized in various applications, including in laboratory equipment for sample analysis, in plant biology for water transport from roots to leaves, and in certain types of thermometers.