H2O, H2O EVERYWHERE

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    Whatever the weather, someone can always be found to complain about it. Either it is too hot and dry and the grass will not grow or the fruit ripen, or it is too cold and wet and the crops cannot be harvested. There are some pessimists who, during a spell of perfect weather, complain that it is too good to last. On balance, however, it is rainy weather that brings most complaints.

Mothers moan that it is too wet for the children to be sent out to play, sportsmen that the golf or cricket or tennis has been rained off, gardeners that the grass is growing faster than it can be cut.

While you make your own complaints for your own particular reasons, you may well be consoling yourself with a cup of tea, having perhaps just had a bath, or washed up after a meal. With a moment’s thought, of course, you will be aware that these activities would be impossible without the rain, as would many others. It would be equally true to say that almost all of the goods and services so necessary to the functioning of a modern society would not be available without the water that falls from the clouds.

Here are a few figures. Four-fifths of the surface of the Earth is covered with water. Each day, a single water company will pump 2000 million litres through more than 30000 kilometres of piping. Sewage disposal doubles these figures. Each person in Western Europe uses about 150 litres of water each day, about five of which are for drinking and cooking, while the rest are used in the pursuit of cleanliness and hygiene. A pint of beer is made with the aid of more than a gallon of water. A ton of steel requires 45000 litres, while a ton of paper needs twice this amount. One could continue with similar statistics for the production of everything else, including food and electric power.

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    Water is clearly the sustaining factor for any kind of civilisation. One could say more. Without water, life itself, in any meaningful form that we can imagine, would be impossible.

Life began in the oceans that circle our planet. It was, relatively speaking, late in the day when the first living creatures crawled hesitantly onto the harshness of the dry land. Those that successfully made the transition carried part of the primordial sea with them, so that even today, the cells of our own bodies are bathed continually in the salty relic of that sea. Water accounts for about 70% of the weight of the human body.

When the first astronauts left the Earth, they looked back on a homely planet teeming with water and life, and forward into a hostility lacking in both. Were the Earth a few miles nearer the sun, its seas and rivers would have boiled off into the atmosphere of a corrosive cauldron, like that to be found on Venus. A few miles more distant, and they would have frozen into an arid, Martian desert. It is only within a limited range of temperature that water is a liquid, and only liquid water can give rise to any active life.

The amazing thing, however, is that water should not be a liquid at all. In terms of chemistry, its nearest neighbours, without exception, are foul smelling, poisonous gases. Think of the tear-drawing sharpness of ammonia, or the rotten egg, stink bomb smell of hydrogen sulphide. There are several other examples. Why is water so different?

As every schoolchild knows, a particle, or molecule of water is formed by a combination of one atom of oxygen with two of hydrogen. Altogether on Earth there are 92 natural elements and a further dozen-or-so man-made ones. It is reasonable to assume that, in the entire universe, there are no more. When these elements join together, to form every material in existence, including our own bodies, they are held in place by very tenuous entities called electrons. Of all the elements, only three have the ability to hold onto electrons to an extreme degree. One of these elements is oxygen. The result is that when oxygen combines with hydrogen, the product, water, is electrically very highly charged, so much so that the particles, in a sense, become sticky, and tend to cling together much more than they should. The consequences of this single property are far-reaching, and crucial to the existence and maintenance of life on Earth.

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    The liquid nature of water is one consequence. Because the particles stick together so tenaciously, a large amount of energy is needed to separate them. This means that water boils at a much higher temperature than do other similar substances. Another result is the amazing capacity of water to absorb and hold heat, which enables the seas to regulate the temperature of the planet within the limits necessary for the survival of life.

As the water freezes, its stickiness is accommodated by an adjustment of the particles around each other in such a way that, unlike any other liquid, it expands, so that ice will form only on the top of a lake, leaving warmer fluid, in which fish can swim and plants grow, underneath.

On the surface of a pond, the stickiness of the particles causes a skin to form, on which insects can skate. A disadvantage of this is that, for the purpose of washing, soap or a detergent must be added to break the skin.

The same property helps trees to lift water to their topmost branches, along with the nutrients dissolved from the soil by the same water. It is also responsible for the hexagonal symmetry and delicate beauty of a snowflake. It captures the light of the sun, breaks it into fragments, and flings it down to us in the transient glory of a rainbow, reminding us that the storm, however heavy, must come to an end.

So if it is raining, look at that drop that has just splashed onto your window, and reflect, for a few moments, on the remarkable secrets it holds. Don’t complain. Be thankful for it.

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