HOW MUCH WATER EXISTS?

The alarm-clock sounds at twenty past six, like each morning, and Bill arranges himself to initiate a new day. He goes to the washstand; he opens the cold faucet to refresh himself and to rinse its still semi enclosed eyes. It takes its toothbrush, while litres and litres of water go away by the water-drainage. With his calm and tranquillity he takes his Gillette to shave himself clarifying the blade with that enormous and infinite amount of water that leaves by that miraculous faucet. It is the time for the shower, and there is anything better like the sensation to feel litters and litters of water to slide by his skin during along fifteen minutes at least.

Without any doubt, our Bill, a really good person at the end, does not know the availability of the potable water for the world-wide population. Like other people, he thinks water is a cheap and an inexhaustible resource, so he can have it when he wants. Is it really like this? We should stop and analyze how much water we have.

First of all, it is important to know water is a compound whose molecule is formed by two atoms of hydrogen and one of oxygen. Are these elements difficult to find in the universe? The answer is no, in fact the most abundant elements in the universe they are, in order: hydrogen, helium, oxygen and neon. Helium and the neon are noble gases and they cannot form compounds, so we have only hydrogen and oxygen, which as we had seen, take place together to form the famous water molecule. It is the reason why we can predict without any doubt that the water is the most abundant compound in the universe.

And now, we know that water exists in great amount, but we do not know where it is concentrated. If we watched the sky in a cleared night we would see a myriad of stars and with a little of lucky one of the branches of the milky route, the galaxy in which we live. Is there any water in stars? It is obvious that the answer is fully no, since the heat, that they generate, dissociates the hydrogen molecule and oxygen one, so it is not viable that they contain any water form.

And what is about the small bodies like asteroids, certain satellites, small planets? In these cases the gravitational power of these bodies are not enough strong to hold the light molecule of water, so it could only persist a small amount related by forces chemistries to the rocky crust.

Then, where have we got all that amount of water? The answer is easy, it is dispersed by the universe forming clouds and water concentrations; it is also contained in comets when they are so distant of the stars, that the little heat they receive is not able to evaporate the ice, so this cannot escape to the deep space; and finally it is dispersed in bodies with medium or great size whose gravity allows to retain it, as planets with a considerable size like the Earth.

In addition to this, our planet has the ideal temperature so the water in its three phases coexists without abrupt changes of temperature; thanks to this we have water available. The Earth surface is covered with about 205 million kilometres at the great ocean, so it represents more than 71% of total surface of the planet. The other 29% is only in the floor that we walk. But not only the surface covered with water represents chilling data, if we consider the volume of this water with an average of depth of 3.750 meters , we are speaking of a volume of water of 524 million cubical kilometres, that expressed in litters they would be 524*10¹⁸ , it means : ¡524 followed of 18 zeros!. The ocean water represents therefore the 97.2 % of the total water and every year 128000 Km 3 are evaporated of the sea in order to become in rain or snow. Thanks to that we can have about 320000 Km3 of water under the surface of the continent and about 48000 Km¹⁸ on the same, in form of rivers and lakes. As we see, there is much water on the Earth, and we could say that in its surface it is really the only liquid that exists in certain amount. Unfortunately, all this water of that we arrange is not good for human consumption, since the one, which is in the sea, has a high content of salts too much elevated. That's a consequence of the development of the history of our planet, since the cycle of the water was repeating time and time and it evaporated water of the sea to form mainland rivers again. When this water crossed the channels, rocks and stones were eroding, so water was dissolving them and dragging them to the sea. Step by step it was increasing throughout the million years its saline concentration.

What have we got? Only a 2.5% of fresh water respect to the total amount that we had in the Earth. However, all amount of water is not accessible for us, since 70% of the same one are congealed and concentrated in the polar caps. That's why we have a 0.75% of sweet water in liquid state. This amount of water is not either available since most of it is integrated on the humidity of the Earth and another part is in places with great depth or completely inaccessible. In conclusion, we have only a 0.0025% of potable water accessible that can be used for human consumption.

Therefore we can be happy, since nature has granted us the luck to have enough amount of a compound indispensable for the life and with its miraculous properties. We have a planet that join in an exact form the perfect conditions to be able, not only to have this called wonder water, but of in addition to have in its more appraised state, the liquid one. However, as we have seen, only the 0.0025% of this water is able to cover our necessities. The demographic increase and the progressive contamination of our resources, as well as their overused, is causing that this minimum number descends every year more and more until the point of which in certain areas of our planet, potable water begins to be a good little and very appraised. If we continue on this way, it is prevent in 2025 two of each three people in the world will live in a state of hydro deficit without having enough amount of water to consume. It depends on all of us to maintain these resources by means of a suitable used and management of such.