The cells of our body are bathed in water. It circulates throughout our bodies in our blood vessels. Water is intimately involved in all aspects of life. No other substance is as important for life.
Water is constantly moving, circulating over the Earth's surface in ocean currents, or drawn downhill to the sea by Earth's gravity, or up into the atmosphere.
Water is drawn up into the atmosphere by solar powered evaporation, it forms into clouds and falls again to Earth as rain, sometimes in the sea and sometimes on land.
When it falls on land some of it ends up as groundwater, some in lakes. But all is drawn to the sea by Earth's gravity. It is the triple actions of the Sun's radiation, the Earth's gravity, and its centrifugal motion that creates the water cycle on Earth's surface
As if to mirror what goes on on the face of the Earth, water in the form of blood is pumped and circulated throughout our bodies by our hearts. This coordinated internal flow of water provides us with food in the form of dissolved carbohydrates , dissolved oxygen, and electrolytes; It gets rid of wastes; It carries immune cells that protect us from disease, white blood cells and platelets that help to repair the body and hormones and chemical transmitters that communicate information from one organ to another.
Water is not just water. It is the universal solvent. It can hold an unbelievable amount of different molecules in solution. Water is constantly in motion, carrying things, carrying chemicals in solution, carbonic acid, which eats away at minerals and carrying sulphates, phosphates, carbonates, and oxides to the sea.
Streams and rivers carry aluminum and magnesium silicates in suspension, and carry rocks and boulders down stream , depositing sediments on the edge of the continental shelves. Over vast scales of time water recycles all the major elements of life except nitrogen.
No-one can survive without water. Not only do we have to drink it every day, but we wash in it, cook with it, clean with it, use it in manufacturing, use it in transportation, and in recreation.
Without water we wouldn't be able to make cement and even our houses would lack a foundation. It's indespensible in religion, where it signifies holiness, purity, and rebirth
Water is the mother of life. The very first living cell was born in water, All of us were conceived and gestated in water. When we are born, we are born from out of our mother's water.
We find ourselves drawn to water, and feel it's calmness, it's churning, it's raging, and it's bubbling. Houses with a water view are worth more money because of the positive psychological effect of seeing water.
But water by itself is not sufficient for life. Without the Earth in it's special relationship with the Sun, and the Earth's size and shape to hold and channel the water, life could not have existed.
What do I mean by Earth's special relationship with the Sun? We know that the Earth, unlike the rest of the planets is just the right distance away from the sun to keep most of the water on Earth in a liquid state. Not to cold to freeze everything and not too hot to boil it all away.
Water is necessary for life, but it's got to be largely in liquid form for life to have originated and for life to continue. That's because life's metabolic processes, the ways that living things get energy, all happen in liquid water.
When, cells photosynthesize it happens in water; When cells do respiration it happens in water; When cells divide it happens in water. All the molecular reactions that are necessary for life work in water and never outside it.
That doesn't mean that water isn't important to life in it's non-liquid phases. Right now 2.9 % of Earth's water is locked away in glacial ice. Over millions of years the glaciers ebb and flow creating ice ages and lowering sea levels then mysteriously stopping their advance over the Continents, retreating towards the poles and making the oceans rise during warmer times.
Water vapour is a more powerful greenhouse gas than carbon dioxide but the reason it does not play as important a role as carbon dioxide in global warming is because a water molecule only stays in the atmosphere for a matter of days, whereas a molecule of carbon dioxide can stay in the atmosphere for hundreds of years.
97% of Earth's water lies in the great oceans. Because water has one of the highest heat capacities of any substance, second only to ammonia, the Earth's oceans play an important role in moderating and regulating climate and temperature. Tune in next week when I talk about the effect of water on global temperature regulation.
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