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hidaayah
02-02-2006, 04:22 PM
If Ice Didn't Float…
By Harun Yahya


There are many places in the world where the temperature falls below 0°C in winter.


Most of our planet is covered with water. Oceans and seas make up three fourths of the earth’s surface while the land itself contains countless numbers of rivers and lakes. The snow and ice on the summits of lofty mountains is water in its frozen form. A substantial part of the earth’s water is in the sky: every cloud contains thousands—sometimes millions-of tons of water in the form of vapour. From time to time, some of this water vapour turns into drops of liquid and falls to the ground: in other words, it rains. Even the air you’re breathing now contains a certain amount of water vapour.


In short, no matter where you may look on the surface of the earth, you are certain to see water around somewhere. Indeed, the place you are sitting in at this moment probably contains about 40 to 50 litres of water in it. Look around. You can’t see it? Look again, more carefully, this time raising your eyes from these words and look at your hands, arms, legs, and body. That 40-50 litre mass of water is you!


It’s you because about 70 per cent of the human body is water. The biggest part of the blood that circulates everywhere in your body is of course water.


Other liquids freeze from the bottom up; water freezes from the top down. This is one of the most unusual properties of water and it is crucial for the existence of water on the surface of the earth. Were it not for this property, that is, if ice didn’t float, much of our planet’s water would be locked up in ice and life would be impossible in its seas, lakes, ponds and rivers.


There are many places in the world where the temperature falls below 0°C in winter, often considerably below that. Such cold will of course affect the water in seas, lakes, etc. These bodies of water grow colder and colder and parts of them begin to freeze. If ice didn’t behave the way it does (if it didn’t float in other words) this ice would sink to the bottom while the warmer bits of water would rise to the surface and be exposed to the air. But the temperature of that air is still below freezing point so these will freeze too and sink to the bottom. This process would continue until there was no liquid water left at all. But this isn’t what happens. What happens instead is this: As it gets colder, water grows heavier until it reaches 4°C at which point everything suddenly changes. After this, the water begins to expand and it becomes lighter as the temperature drops. As a result, the 4°C water remains on the bottom, the 3°C water above it, the 2°C water above that and so on. Only at the surface does the temperature of the water actually reach 0°C and there it freezes. But only the surface has frozen: the 4°C layer of water beneath the ice remains liquid and that is enough for underwater creatures and plants to continue to live.


We should note here that another property of water-the low thermal conductivity of ice and snow-is also crucial in this process. Because they are such poor conductors of heat, the layers of ice and snow keep the heat in the water below from escaping into the atmosphere. As a result of all this, even if the air temperature falls to -50°C, the layer of sea ice will never be more than a meter or two thick and there will be many fractures in it. Creatures such as seals and penguins that dwell in polar regions can take advantage of this to reach the water beneath the ice.


In water, God has given us life and with it, He causes the food by which we are nourished to spring from the soil.


But the most important aspect of all this is that this truth, which has been discovered by modern science, was revealed in the Qur’an, bestowed upon humanity as a guide fourteen centuries ago. Concerning water and mankind, Allah’s word is revealed in the Qur’an:


“It is He who sends down water from the sky. From it you drink and from it come the shrubs among which you graze your herds. And by it He makes crops grow for you and olives and dates and grapes and fruit of every kind. There is certainly a Sign in that for people who reflect”. (Surah Al-Nahl: 10-11)
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