Attraction capillary refers to the phenomenon in which liquid, usually water, is drawn up into small open tubes or capillaries due to the combined forces of adhesion and cohesion. Adhesion is the attraction between the liquid molecules and the molecules of the capillary walls, while cohesion is the attraction between the liquid molecules themselves.
The concept of attraction capillary is based on the understanding that when a liquid comes in contact with a narrow tube or capillary, the liquid molecules experience stronger attractive forces on the tube's inner surface than among themselves. This disparity in attractive forces pulls the liquid upward, against the force of gravity, resulting in the climb of the liquid within the capillary.
The extent to which attraction capillary occurs depends on various factors, including the diameter of the capillary, the surface tension of the liquid, and the angle of contact between the liquid and capillary walls. Smaller capillaries tend to exhibit a greater level of attraction capillary, as the adhesive forces dominate over gravity more prominently.
Attraction capillary is a phenomenon commonly observed in nature, such as the upward movement of water in plants' xylem vessels, the absorption of water by a paper towel, or the ascent of water in a narrow glass tube when in contact with a water source. It also plays a critical role in the functioning of biological systems, laboratory experiments, and numerous industrial applications, such as inkjet printing, chromatography, and the transportation of various fluids in microfluidic devices.
