Day: November 16, 2016

Capillary action

Capillary action

Capillary action

11/16/16

“Why is it that liquids can move up against gravity in containers?”

 

Liquids are objects that we often see everyday, whether it be in the water that we drink or in the blood that runs through our veins. We also know that objects are held down to the Earth by gravity, but for some ominous reason liquids seem to have the ability to move upwards by themselves in a container against gravity. Why is this so? Well, like I always say, let’s think about it. When liquids are placed in containers, a concave meniscus will form from adhesive forces. If the diameter of the containing vessel is small enough, then the adhesive forces from the container will cause a vertical force on the fluid, and if these adhesive forces are more powerful than the internal cohesive forces will pull the liquid along with it, therefore causing vertical movement. Because this phenomena is so special not only has it been given a special name by scientists and engineers (Capillary action), it is found in many wonderful applications in nature. Plants use capillary action to absorb water from the soil using their roots, and human eyes utilize capillary action using two small diameter tubes called the lacrimal ducts to drain tear fluid in the eyes.