- What is water Why does it wet?
- Action examples
- How is this property of water used?
- Wetlands: an even clearer example
- References
The reason why water gets wet is due to the existence of two forces: "cohesion forces", which is the force that hold the water molecule (H2O) together, and "adhesion forces", which is the force that manifests itself when water comes into contact with another surface.
When the cohesion forces are less than those of adherence, the liquid “wets” (water) and logically, when the cohesion forces are greater, the liquid will not wet (Iefangel, 2008).
What is water Why does it wet?
Water is the main element on which life in the biosphere revolves, since it allows us to hydrate living beings and soils. It occurs in the three physical states (solid, liquid and gaseous) and has several stages in its cycle: precipitation, condensation and evaporation. This element is vital for the biochemical functioning of the organism of living beings.
Water is a simple molecule made up of small atoms, two hydrogen and one oxygen, linked by a covalent bond. That is, the two hydrogen atoms and the oxygen atoms are joined by sharing electrons. Its formula is H2O.
It has an irregular distribution of electron density, since oxygen, one of the most electronegative elements, attracts electrons from both covalent bonds to itself, so that the highest electronic density (negative charge) is concentrated around the oxygen atom and near of hydrogens the least (positive charge) (Carbajal, 2012).
Its chemical formula is H2O, composed of two electronegatively charged hydrogen atoms and one electronegatively charged oxygen atom. Wetting involves sticking to a solid surface.
By having more adhesion force, it becomes possible for the water molecule to stay together due to intermolecular forces. In this way, the water gives its appearance of humidity - wet - on surfaces such as cotton, polyester or linen fabrics, among others.
As there is greater cohesion force, the water particles are held together and are adjacent to the surfaces with which they come in contact, for example paneled walls, finished floors, etc.
Action examples
If we take two pieces of glass, wet their inner faces and then join them together, it will be virtually impossible to separate them without sliding them, since the force that would be required to remove them if we pull perpendicularly is very great; If they are allowed to dry, they can be separated without difficulty: the cohesion of the water molecules acts as a holding force (Guerrero, 2006).
It can be seen in the example that the two pieces of glass are wetted on their lower faces, they have more cohesion force, generating that the water particles remain united without combining with those of the glass. As the water dries, stains of it remain on the pieces.
If we put a thin tube in a container with water, it will "climb" inside it; The reason? A combination of the cohesion of the molecules with their adhesion to the walls of the tube: the adhesion forces between the molecules of the tube and those of the water attract them to the walls of the tube and this gives a curvature to the tube. water surface (Guerrero, 2006).
The adhesion forces are greater than the cohesion forces, which allows the tube to be raised by the water molecules towards the surface. On the assumption that the tube were made of cardboard, it would undergo changes in its structure due to the absorption of water molecules.
How is this property of water used?
In agriculture, vegetables and other products need to be watered for their growth.
Water adheres to these and, once harvested, they can be raw materials. There may be cases of vegetables, grains and fruits that have water content, which must be processed through drying and / or dehydration processes for the production and subsequent marketing of solid foods such as: dairy products, coffee or grains, among others.
To dry or dehydrate raw materials, it is necessary to calculate the percentage of wet mass and dry mass.
The great engines of water among living things are plants. The water wets the roots of the plants and they absorb it. Some of the content of this water is used within the body of the plant, but the liquid flows to the surface of the plant leaf.
When the water reaches the leaves, it is exposed to air and solar energy, it is easily evaporated. This is called perspiration. All of these processes work together to move water around, through, and on Earth.
Wetlands: an even clearer example
Wetlands are areas covered by land or saturated with water, depending on the area and the corresponding season. When the level of the vital liquid rises, it covers the plants that adapt in that area to be able to develop the process of transpiration and photosynthesis. It also allows different animal species to come alive.
The hydrology of wetlands has the following characteristics: the amount of nutrients that enter and leave, the chemical composition of the water and soil, the plants that grow, the animals that live and the productivity of the wetland.
Wetlands have productivity according to the amount of carbon that plants release during the photosynthesis process, which is enhanced by the flow of water.
The swamps and valleys and depressions at the bottom of the hydrographic accounts have a high biological productivity because they have few restrictions for photosynthesis and because they contain a lot of water and nutrients compared to the mainland.
When they are wetlands of low productivity, they only receive water from the rains, they have simpler plants and there is a slower decrease in plant material, which accumulates as peat.
The action of man has brought as a consequence that the water levels that cover the wetlands have fallen, due to the use of these for agricultural activities and the discharge of sewage - with fertilizers - to them. Urban growth has also reduced hydrological catchment.
References
- Water: A heritage that circulates from hand to hand. Recovered from: banrepcultural.org.
- Carbajal, A. (2012). Biological Properties and Functions of Water. Madrid, Complutense University of Madrid.
- Guerrero, M. (2012). Water. Mexico City, Fondo de Cultura Económica.
- Project Wet International Foundation and CEE: The Incredible Journey. Recovered from: files.dnr.state.mn.us.
- Understanding the 'wet' in wetlands. A guide to the management of freshwater wetland hydrology. Recovered from: gw.govt.nz.
- Wilhelm, L. et al (2014). Food & Process Engineering Technology. Michigan, American Society of Agricultural Engineers.
- Your answers to 10 tricky children's questions. Recovered from news.bbc.co.uk.