Introduction
Water is a chemical substance that has molecules made up of two hydrogen atoms and one oxygen atom. It is represented by the chemical formula H 2 O and has the following physical and chemical characteristics:
1. Tasteless: water does not and should not have any taste.
2. Colorless: water has no color.
3. odorless: the water does not and should not have any odor.
Furthermore, in chemical terms, water is considered a universal solvent, that is, most of the substances found on the planet can dissolve in an aqueous medium.
Water and life on the planet
This substance is one of the most important and essential natural resources for life on planet Earth. Plants, animals, all living beings on the planet need water to be able to live, as a large part of our cells is formed by water. The human body has an amount of water that varies between 70 and 75% of its composition.
In addition to being essential for life, water is also used by humans for fishing, irrigating crops, transport, and producing electricity. Directly or indirectly, human life, its development, and even its comfort are linked to water.
Earth, water planet?
If we analyze the Earth’s surface, around 70% of it is made up of water – that is, only the remaining 30% is, in fact, the Earth’s surface.
However, if the analysis is carried out taking into account the volume of the Earth, the composition will present much smaller percentages of water, since it is not present in abundance within the planet. Therefore, only from the analysis of the surface can the Earth be called a water planet.
water cycle
The so-called Water Cycle, or Hydrological Cycle, is the permanent process of water transformation. The substance passes from one state (solid, liquid or gaseous) to another through the processes of evaporation, condensation, rain or precipitation, infiltration, and transpiration.
The water cycle contributes to the maintenance of life on Earth, in addition to influencing climate change and the volume of rivers, seas and oceans. Its processes are developed in five steps:
1. Evaporation: The heat from the sun warms rivers, seas, and lakes. As the water heats up, it evaporates and changes from a liquid to a gaseous state and moves from the Earth’s surface towards the atmosphere.
2. Condensation: Water vapor cools and goes through the condensation process, that is, water goes from a gaseous state to a liquid and becomes water droplets that are found in clouds.
3. Precipitation: The large quantity of water droplets causes the clouds to become heavy, causing the water to precipitate, forming rain. In very cold places, precipitation can go from liquid to solid, causing hailstorms.
4. Infiltration: When falling on the earth’s surface, water infiltrates the soil and contributes to the formation of groundwater.
5. Transpiration: Finally, the water infiltrated into the soil is absorbed by plants, which return the water droplets to the environment through plant transpiration.
Potable water
All water suitable for human consumption and irrigation of plants must be potable, that is, it must be free of toxic materials and contaminants, as well as microorganisms, such as bacteria, protozoa or even fungi.
The consumption of clean water is essential to avoid contamination of humans and animals that consume it, as well as avoiding contamination of irrigated fruits and vegetables. To ensure that the water used is drinkable, the substance needs to pass through treatment plants, which will guarantee the quality of the water that will be distributed.
Even though drinking water is indispensable for human consumption and agricultural production, even considering the fact that the increase in its consumption has increased more than ten times in the last century, it is estimated that millions of inhabitants in the world still do not have access to drinking water. In reality, many do not even have access to precariously clean water.