What is capillary action?
‘Capillary action’ is a process wherein fluids are able to flow through seemingly narrow spaces without any form of assistance. This particular property of liquids is also referred to as ‘capillarity,’ and the process is able to go on despite external forces that may act on them like gravity and/or friction from the narrow space. The process of capillary action is made possible mainly by two liquid properties namely cohesion and adhesion. ‘Cohesion’ refers to the likelihood of liquid substances binding together. ‘Adhesion,’ meanwhile, involves the behavior of various liquid substances to combine with each other despite their differences in composition. With both properties present in liquids, moving upwards through a narrow space can always be achieved.
Capillarity or capillary action can best be explained with the way plants are able to nourish each branch or each leaf by absorbing water from their roots. When one thinks of it, getting the water from the roots and up to all the leaves of a tree may be a daunting if yet an impossible task. Through the water’s capillary action, though, the seemingly difficult task of reaching the upper parts of the tree can be achieved. Through the xylem or the capillary network in plants, water and other nutrients are able to reach the different branches, leaves, and flowers, for example. The xylem is composed of cellulose fibers which make the water adhere to them. As the water adheres to these fibers, it will create meniscal edges on the xylem which literally pushes them up. Through this process, water from the roots will be able to go up and nourish the different parts of a plant.
Capillary action is also dependent on various factors including liquid density, level of liquid cohesion, and the space involved. With denser and more cohesive liquids, the capillary action may slow down because of the liquid’s tendency to stay put and stick to other substances or surfaces.