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M r. UNIQUE
高校生：「水は無味、無臭、無色透明で、物理・化学的に特に注目すべき特徴もないし、
この地球上のどこにでもある最もありふれた物質だと思う。」
It is true that water is, in fact, tasteless, odourless, and colourless.
However, it is important to take a moment to realise that only water, and perhaps air, are the two sole substances known to humankind with those three magical qualities. Without it, our planet earth would have been a completely different sight, let alone have any living organism to witness it. Let us look at water today and its importance through the following aspects.
Unusual properties:-
Water is very unusual to say the least. It is the only substance that can exist as a solid (ice), liquid (water) and gas (vapour). In addition, water is the only substance whereby the liquid is denser than the solid. This is precisely why ice cubes are able to float in a glass of water, and how life can exist under the frozen surface of lakes through the cold hibernal months. Its large heat capacity and high thermal conductivity are the key to our ready-installed thermostat.
Many things are soluble in water and thus plays a crucial role in transporting minerals in the circulatory system of living organisms, hence the name “universal solvent”; it may be the veins in animals, or xylems in plants. These are some of the properties of water that sustain the lives of each and every one of us. Its surface tension enables pond skaters to float, waiting for their prey to fall.
Furthermore, its surface tension enables capillary action to occur and plants to grow vertically. Water’s cohesion causes water drops to form on plant leaves due to its polar nature, and adhesion maintains them there.
Nature:-
Water is everywhere, or so it seems, and it takes many different forms as it circulates in the hydrosphere. Water is vital to life and it falls into our hands most often in the form of rain. However, too much rain could cause a flood, and too little of it dehydrates the surface and causes drought. Both are very destructive and result in devastating consequences. Water also provides habitats to aquatic wildlife and plants, and it is due to its transparency that sunlight is able to shine through it and allow photosynthesis to occur. It is evident
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that water is a life-saving substance that nourishes the planet, and yet it is a life-threatening substance in large quantities, as we saw in the Thailand Tsunami disaster, or the daily loses in the mere sea current that swallows many innocent lives.
Industry:-
The water industry in developed countries is very well organised in providing running water, and because of this, any one of us can turn the tap and expect clean water to flow out, or for our waste products to be flushed so as to maintain our hygiene level. There are many facilities that collect, purify and supply water to meet our needs. The extent to develop our water supply portrays the importance and our perpetual need for it.
Quality of life:-
While the body can survive without food for approximately five weeks, the body cannot survive without water for longer than five days. Over a third of our body (roughly 70%) is composed of water and it has many functions within.
Even the slightest level of dehydration can decrease the body’s metabolism and affect the body’s physical and mental performance. Dehydration is also a primary cause to day-time fatigue. Without water, our lives would be so much more disagreeable, to put it mildly.
Universal:-
The demand for water is universal, and the lack of it in developing parts of the world is of a global concern. In fact, it is one of the Millennium Development Goals to halve the number of people without sustainable access to safe drinking water by 2015. The world is overpopulated, resulting in mass consumption and misuse of water simultaneously. Because of pollution, the amount of clean water available per capita is nowhere near adequate. To worsen the situation, in some areas water bears diseases to communities where there are no vaccinations. This often leads to deaths in many undeveloped countries.
Earth:-
Even though, water is transparent in small quantities, it essentially has a shade of blue when there is a great mass of either it; this is why our planet
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seemed blue from afar as Gagarin said. Green plants also cover the earth’s surface and water is a necessary element to their growth. A light sprinkle of water in the sky refracts and disperses the sunlight to exhibit a spectrum of light, thus colouring the never-ending canvas with the pleasures of a multicoloured arc or two. It is as if water is a painter. But as equally creative, is its architectural nature. Acidic rain falls to erode and freeze-thaw action occurs that splits the mightiest of rocks. Water is a true artist in shaping our planet.
Many aspects of water were explored, with many more left to be mentioned.
Water is a very interesting and complex substance with many unanswered questions, and is therefore far from being a substance of no significance. It is our responsibility to look after it and to treat it with respect; never take it for granted.
Reference
Wikipedia – Water & Adhesion
http://en.wikipedia.org/wiki/Water#Chemical_and_physical_properties http://en.wikipedia.org/wiki/Adhesion
Water anomalies –
http://www.lsbu.ac.uk/water/anmlies.html
WikiAnsweres – How long can a human survive without food or water
http://wiki.answers.com/Q/How_long_can_a_human_survive_without_food_or_
water
