Kapillaariputkeenilmiö

Kapillaariputkeenilmiö, also known as capillary action, is the ability of a liquid to flow in narrow spaces without the assistance of, or even in opposition to, external forces like gravity. This phenomenon occurs due to the interplay of cohesive forces between liquid molecules and adhesive forces between the liquid and the surrounding solid surface. When the adhesive forces are stronger than the cohesive forces, the liquid "wets" the surface, and capillary action draws the liquid upwards. Conversely, if cohesive forces dominate, the liquid will not wet the surface and may be pushed down.

The height to which a liquid rises in a capillary tube depends on several factors. The surface tension of the liquid, the contact angle between the liquid and the tube's wall, the radius of the tube, and the density of the liquid all play a role. A narrower tube will result in a higher rise of the liquid because the surface area of the liquid in contact with the tube wall is relatively larger.

Capillary action is observed in various natural and man-made phenomena. It is crucial for water transport in plants, where it allows water to move from the soil up through the xylem vessels to the leaves. In everyday life, capillary action is responsible for the wicking effect seen in paper towels, sponges, and candles. It also plays a role in ink transfer in pens and the movement of oil in lamps. Understanding capillary action is important in fields like fluid dynamics, material science, and biology.