“The principle of all things is water, because water is everything and everything turns back into water.” Thales of Miletus (624-546 BC)

Water is a clear, odorless and tasteless, colorless, transparent liquid. It can solve liquids, gases and solids. Water consists of two atoms of hydrogen and one atom of oxygen (H2O). The atoms in water molecules are not exactly arranged in series, but in triangular form. The molecules attract each other via the “hydrogen bonds” and thus ensure the surface tension of water. This tension is immediately apparent: if you carefully puts a paper clip to a full glass of water, it remains on the surface. As simple as the fabric is constructed from which all life depends on the earth.

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A lot of water – less water

Large parts of the earth is covered by water, a total of 1.4 trillion liters. But only 2.5% of them (35 million km3) is fresh water. Two thirds of this freshwater is not as glaciers or ice at the poles in the ground or in the atmosphere used. Humans remains only a small part of the world’s water for drinking. Hydrologists estimate that only 0.14 per thousand are of the earth’s water for the people directly inferable than fresh water. The ocean covers 71% of the earth’s surface and produces 70% of the oxygen we breathe. Half the world’s population lives on its shores. The water on earth is not less but more and more people have to share the fresh water resources. The world’s population (about 6 billion) is growing every year by 80 million, while also increasing the per capita consumption of water.

How much water do we need?

Water is also a component of all living things. Some animals are composed almost entirely of water (jellyfish: 99%). Without water, green plants were not capable of photosynthesis. The human body is, according to age and sex, about 2/3 of water. Even small amounts of water to ensure survival in extreme situations, but without it gets. A person usually dies after a maximum of 4 days without fluid, since the metabolism works only if the body has sufficient water is provided. People need each day for about 2 to 2.5 liters of water and about the same amount deposited our bodies on a day off. In our whole Leb s is about 65,000 liters of water, which we eat.