Amanda
Water is an ancient concept, known in Greek as “Aeche”, which originally meant “mother of all things”. It is the basic condition for human and all known life on Earth for survival and isan extremely important and active factor in the social and natural environment, a fundamental natural and strategic resource that sustains the function of the earth's ecosystem and supports the development of social and economic systems. This article is aimed at taking a more in-depth look at water, so if you are interested just keep reading!
01.
What is water?
Water is an inorganic, transparent, tasteless, odourless and nearly colourless chemical substance that occurs on Earth, it is the main constituent of Earth’s hydrosphere and the mainly fluids inside all known living organisms, so that water is very vital for all forms of life on Earth. It covers about 71% of the Earth’s surface, with oceans making up most of the water volume on Earth. Water also plays an important role in the world economy. Approximately 70% of the fresh water used by humans goes to agriculture. Fishing continues to be a major source of food for many parts of the world, providing 6.5% of global protein.
There are a number of natural states of water that exist on the Earth, it could form rain and also fog. Clouds consist of the solid state of suspended droplets of water and ice. When we finely divide water, crystalline ice may precipitate in the form of snow, steam or water vapour is the gaseous state of water.
The structure of water
02.
A water molecule consists of 2 hydrogen atoms covalently bonded to 1 oxygen atom, the H-O-H angle is approximately 104.5 degrees. While the covalent bonding involves the sharing of electrons, they are not shared equally between the atoms. Oxygen has higher electronegativity than Hydrogen, so it attracts the electrons more strongly, the shared electrons orbit closer to the oxygen atom than the hydrogen atoms resulting in polarity.
This molecular structure leads to hydrogen bonding, which is a stabilized structure in which a hydrogen atom is in a line between the oxygen atom on its own molecule and the oxygen atom on another molecule.
03.
The significance of water
(1) Cohesion
Water has the capacity to stay close to each other, due to the collective action of hydrogen bonds between water molecules. This property can cause the surface tension, which is the hydrogen bonding between water molecules that allows the liquid to resist low levels of external force. This surface tension of water makes it sufficiently dense for certain smaller organisms to move along its surface, which helps some certain small insects to stay above the water surface or walk through it.
（2）Adhesion
Water can stick to dissimilar molecules due to its polar nature. The attraction to charged or polar surfaces allows water to flow in opposition to gravitational forces which is called capillary action. This capillary action is necessary to allow water to be transported up plantstems via a transpiration stream.
（3）Thermal properties
Water has the capacity to absorb significant amounts of heat before it changes state. This is due to the extensive hydrogen bonding between water molecules. The H-bonds need to be broken before a change in state can occur, but the breaking down of H-bonds needs a lot of heat energy. This leads to the high thermal capacity of water.
Consequently, water is an excellent medium for living organisms as it is relatively slow to change temperature and thus supports the maintenance of constant conditions.
（4）The universal solvent
Water is commonly referred to as the universal solvent due to its capacity to dissolve a large number of substances. The polar attraction of large quantities of water molecules can sufficiently weaken intermolecular forces in other substances thus resulting in the dissociation of molecules.
This property helps our body to absorb nutrients more efficiently because the big molecule shave already been broken down into smaller molecules that move along the body via blood transport, which let the cells absorb the nutrients.
04.
The water cycle, known ashydrologic cycle, is a biochemistry cycle that describes the continuous movement of water on, above and below the surface of the Earth. It involves the exchange of energy that causes the change of temperature.
Evaporation
Water at the surface of the Earth, in rivers, streams or oceans is heated by the sun. It then evaporates, turns from liquid to gas and becomes water vapour, rising into the atmosphere.
Condensation
All the water in the atmosphere will then eventually be forced to condense from gas into liquid water, in the atmosphere this is done as air rises and cools, and forms clouds in this process.
Precipitation
Within the cloud, the liquid water droplets are likely to merge together over time, forming large droplets. At some point, these droplets may get large enough that they fall from the sky, and depending on the conditions, we may see hail, rain, sleet or snow falling from the clouds.
Collection
After the precipitation, some water may infiltrate the ground and will be collected as the underground water, and finally they will go back into the bodies of water such as rivers, streams or oceans.
ENDING
In terms of a single substance, there is nothing more important and meaningfult o us than water. In terms of complexity and singularity, I'm afraid that water is the top of all other substances. Water offers us infinite possibilities, infinite wonder and infinite inspiration, and it also offers us infinite problems. Every step forward in our understanding of water, the understanding of the world and ourselves will also be improved, this is one of the most fascinating aspects of water and water science.
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