If you like to drink cocktails or other drinks from the tube, you probably noticed that when one of its ends is lowered into the liquid level of the beverage in its somewhat higher than in a cup or glass.Why is this happening?Usually people do not think about it.But the physics of such phenomena have long managed to study well and even gave him his own name - capillary phenomena.Came our turn to find out why this is happening and how the data is explained by the phenomenon.
Why capillary phenomena occur
In nature, everything happening there is a reasonable explanation.If a wetting fluid (e.g., water in a plastic tube), it will rise up the tube, and if the non-wetting (e.g., mercury in glass cones) - then omitted.And the smaller the radius of the capillary, the greater the height of the fluid rises or falls.What explains such capillary phenomena?Physics says that they are the result of the impact of surface tension forces.If you look closely to the surface layer of the liquid in the capillary, it can be noted that in its form, it is a kind of circle.Along its border on the walls of the tube presses the power of so-called surface tension.Moreover, the wetting fluid vector direction it is facing down, and for the non-wetting - up.According to Newton's third law, it inevitably raises equal to the modulo counter pressure.Just make it rise or fall liquid in a narrow tube.This explains the various capillary phenomena.But surely, many have a natural question arose: "And when will stop lifting or lowering of the liquid?" This would be the case when the force of gravity, or Archimedes force balances the force causes fluid to move along the tube.
How can I use the capillary phenomenon?
With one of the applications of this phenomenon which has become widespread in the production of stationery items, familiar to almost every student or pupil.You probably already guessed that we are talking about a capillary stick.
Its structure allows you to write in almost any position, and a thin, clear mark on the paper for a long time made the subject is very popular among the writing fraternity.Capillary phenomena are also widely used in agriculture to control movement and retain moisture in the soil.As you know, the land where crops are grown, has a loose structure, in which between the individual particles are narrow gaps.In fact, it is nothing like the capillaries.As it enters the water to the root system and the plant provides the necessary moisture and beneficial salts.However, these paths and ground water rise up and evaporate quickly enough.To prevent this process, it is necessary to destroy the capillaries.Just for this purpose and carry out loosening the soil.And sometimes there is a reverse situation, when you want to enhance the movement of water through the capillaries.In this case ukatyvayut ground, and thus the number of narrow channels increases.At home capillary phenomena are used in a variety of circumstances.Use blotting paper towels and napkins, use wicks in kerosene lamps and engineering - all this is possible thanks to the presence in their structure of long narrow channel.
