The cohesive forces between the molecules of the liquid are "attempting" to reduce the surface tension i. In doing so, the molecules keep climbing up until a steady state between cohesion and adhesion is achieved with or without the gravity component. This also explains why this phenomenon occurs exclusively in thin tubes also in the absence of gravity.
In wider vessels, only a small fraction of the liquid comes into contact with the vessel walls, and so adhesive forces are negligible and there is hardly any rising of the liquid. And finally an interesting piece of trivia:. Did you know that Albert Einstein's first ever published scientific article deals with capillary action? Adopted from Wikipedia.
Decreased surface tension also increases capillary action. This is because decreased surface tension means that the intermolecular forces are decreased, thus decreasing cohesive forces.
As a result, capillary action will be even greater. Practical use of capillary action is evident in all forms of our daily lives. It makes performing our tasks efficiently and effectively.
Some applications of this unique property include:. When measuring the level of liquid of a test tube or buret, it is imperative to measure at the meniscus line for an accurate reading. It is possible to measure the height represented by h of a test tube, buret, or other liquid column using the formula:. At optimum level, in which a glass tube filled with water is present in air, this formula can determine the height of a specific column of water in meters m :. When certain objects that are porous encounter a liquid medium, it will begin to absorb the liquid at a rate which actually decreases over a period of time.
This formula is written as:. Forces in Capillary Action Three main variables that determine whether a liquid possesses capillary action are: Cohesive force : It is the intermolecular bonding of a substance where its mutual attractiveness forces them to maintain a certain shape of the liquid. Surface tension : This occurs as a result of like molecules, cohesive forces, banding together to form a somewhat impenetrable surface on the body of water.
Adhesive force : When forces of attraction between unlike molecules occur, it is called adhesive forces. This results in the concave formation of water in the capillary tube; this is known as capillary attraction.
Alternatively for mercury, the cohesive forces are stronger than the adhesive forces which allows the the meniscus to bend away from the walls of the capillary tube. These water molecules are still connected to other water molecules below them by the hydrogen bond adhesion and hence tend to pull them up as well. The process repeats till a water column goes up inside the tube. This process is limited by the diameter of the tube as the bigger the diameter the smaller the water column that can climb up.
The reason is that the bigger the column, the more water molecule that are to be pulled up and hence the more the effect of the gravity which is opposite in direction to the capillary action. How do cohesion and adhesion explain capillary action?
Nov 25, Explanation: Water molecules have cohesion forces attracting them to each other due to the hydrogen bonds they have. Related questions How does pH affect plant growth?
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