kapillaarisessa

Kapillaarisessa is a Finnish term that translates to "in the capillary" or "capillary action" in English. It refers to the phenomenon where a liquid in a narrow tube or a porous material rises or falls due to the interplay of adhesive and cohesive forces. This movement occurs against the force of gravity and is a common occurrence in nature and various technological applications.

The upward movement of a liquid in a capillary tube is known as capillary rise. This happens when the adhesive forces between the liquid molecules and the surface of the tube are stronger than the cohesive forces between the liquid molecules themselves. Water in a narrow glass tube is a classic example, where water wets the glass, and the surface tension pulls the liquid up along the edges of the tube, creating a meniscus.

Conversely, capillary depression occurs when the cohesive forces are stronger than the adhesive forces. In this case, the liquid level in the capillary tube will be lower than the surrounding liquid. Mercury in a glass tube exhibits capillary depression because mercury does not wet glass well, and its cohesive forces cause it to form a convex meniscus.

Capillary action is fundamental to many natural processes. For instance, it plays a crucial role in how plants absorb water from the soil through their roots and transport it to their leaves. It is also responsible for the wicking action of materials like paper towels and sponges, allowing them to absorb liquids. In industry, capillary action is utilized in devices such as inkjet printers and chromatographic separation techniques.