Why water is so important for life to exists?


Water is an interesting and unique part of our earth.

Its abundance and availability mark the earth as different from the other planets in our solar system.

We all know from personal experience how, important water is.

Without it we could not have a morning cup of tea or coffee, nor make ice for our cold drink during the hot summer months.

Without it we would have neither steam heat nor water cooled engines in our automobiles.

Probably the most extensive use for water is for irrigation purposes in farming.

This use accounts for about half the fresh water that is used annually.

The next-largest customer for water is, not the home, but the factory.

A large paper mill uses more water each day than does a city of 50,000 people.

But what is it about water that makes it so useful?

What makes water work the way it does?

Water is one of the most interesting of all the chemical compounds, being a mixture of two gases that combine to form, not another gas, but a liquid.

This, in turn, can be solidified and used as ice or heated into steam, acquiring even more interesting properties.

The formula for water was proved when the two gases hydrogen and oxygen were exploded by an electrical current.

The result was water, and an amazing property of water was thus discovered.

When two of the most volatile gases known are exploded together, the result is, not a tire, but water, the substance used to put tires out!

There is a definite chemical relationship between the two gases when combining to form water.

From the viewpoint of their relative weights, it takes one part by weight of hydrogen to combine with exactly eight parts by weight of oxygen.

Oxygen is a much heavier element than hydrogen, so, from the viewpoint of the volumes of the gases instead of their weights, it takes two volumes of hydrogen to combine with one volume of oxygen to get, not three, but two volumes of water vapor.

This is because the 2H combine with O to form a molecule of H20.

And how large is this molecule?

It takes about a trillion trillion of them to make an ounce of water.


The universal solvent

Red ink dissolving in a glass of water.

One of the most important properties of water is its power to  a great variety of different compounds.

There is no liquid on earth that can surpass water for its practical solvent qualities.

With good reason it has been called the “universal solvent.” 

Especially is water a vital solvent for living things.

Since all the different substances that comprise protoplasm (the essential substance of both the cell body and the cell nucleus) are either soluble in water or can be suspended in it, water is an essential means of transporting nutrients to the cells and of carrying away the waste products.

Every organic process occurs in a watery medium; for example, respiration and digestion.

Blood really is composed of about 90 percent water.

A large volume of blood is necessary at all times to carry oxygen to the tissues and to carry away waste products.

Adequate water must be maintained in the body tissues as well.

For example, adult muscle is from 80 to 90 percent water.

All tissues contain water in their protoplasm.

In terms of total body weight, water makes up over two-thirds of the human body.

What happens when one does not get enough water?

The water content in the tissues lowers and the blood becomes more concentrated.

This means that the blood cannot circulate as freely, and its oxygen carrying capacity is reduced.

The tissues do not receive the oxygen they need.

Waste products begin to accumulate in the tissues.

If water is not obtained soon enough, the functions of the body eventually stop and death results.

It is thought that one cannot live if he loses about 20 percent of the water in his body.


Water and good health

A man and woman drinking water.

If we are to stay alive, we must have water, and that almost daily.

It has been observed that some animals can live as long as three months and sometimes more without food, but they will die in five to ten days when they cannot get water.

How much water is necessary for good health?

That depends on physical condition, weight, age and other factors.

Under ordinary conditions the adult human body loses about fifty fluid ounces of water a day.

Of this about twenty ounces is lost through the skin as perspiration, another thirteen ounces in the air exhaled through the lungs, and the balance, about seventeen ounces, in the urine.

Naturally this varies with each individual.

For good health this lost water must be replaced daily.

Not all need be taken as fluids; some is obtained in the food we eat.

Fruits and vegetables contain from 80 percent to 90 percent water, and milk about 87 percent. In the normal diet we can expect to take in from one and a half to two pints of water a day, including the water that is present in food and that which is formed by the body in the oxidation of food.

How does the body make water by oxidation?

It has been observed that when one molecule of glucose is oxidized in digestion, six molecules of water are produced.

Where did the water come from?

From inside the glucose molecule, which has many hydrogen and oxygen atoms in its structure.

When that molecule is broken up by the influence of gastric juices and enzymes, other products are produced, and the leftover hydrogen and oxygen atoms are combined by the body to form water.

In this manner, the body can manufacture some water for itself; indeed, some animals, such as certain desert dwelling rodents, can make so much water that they never need to take a drink!

In humans it has been estimated that a person producing 2,400 calories of heat per day can obtain about ten fluid ounces of water as a result of this oxidation of food.

Such water is sometimes called “metabolic water.”

How plants use water?

Water droplets on leaves.

Plant life is greatly affected by the abundance or lack of available water.

In the study of trees we can learn much about how water is utilized in other plants.

About 75 percent of the weight of a tree either is water or is made from water.

All the food for the tree, the nitrates and the minerals, is absorbed from the ground.

To be carried into the tree the nitrates and minerals must be soluble in water.
There may be present in the earth certain chemical elements, but if they are bound in compounds that are not water soluble they cannot be carried into the tree.

Carbon dioxide is another product that the tree must have in order to grow.

It enters the tree through the leaves, but cannot be used until it is dissolved in the water inside the tree.

Once inside the tree the elements can be used in the vital processes of life because the water transports them to different parts of the tree.

Another important role that the water plays in the tree is in maintaining “tungor", which is the normal tension on the cell wall necessary for the support of the cell.

Plant cells utilize water in yet another way.

This is in what is called “bound water.”

This differs from free water in that it is combined either physically or chemically as a part of the molecule in the plant.

This “bound water” is very difficult to separate from the molecule since it actually is a part of the molecule itself.

At low temperatures this water does not freeze and cannot be rendered useless by winter weather.

At high temperatures it is not lost through evaporation.

Naturally this has many advantages to the plant.

Bound water is of special interest in connection with the ability of plants to resist low temperatures and drought.

Winter wheat is planted in the fall and produces its crop the following summer.

A severe winter will kill many varieties of winter wheat, but a hardy variety of winter wheat may contain three or four times as much bound water as a non-hardy variety.

Drought-resistant grasses may contain ten times as much bound water as non~ drought-resistant varieties.

Chemical and physical properties of water

A drop of water falling into a pool of water.

Water has other useful properties that make it work in many ways for our benefit.

For instance, water has almost the greatest heat-absorbing capacity of known substances (bromine and hydrogen being two exceptions).

How is this property useful?

For one thing, water, in the form of oceans and lakes, acts as a cushion against the rising and the falling of temperatures and therefore makes a more comfortable climate in the areas where there are large bodies of water.

In the regulation of body heat, water has an important role to play.

This is because it possesses what is termed “high specific heat.”

This enables the body to store heat effectively without greatly raising the temperature. It also has “high heat conductivity.”

This property permits heat to be transferred readily from the interior of the body to the surface.

Finally, water possesses “high latent heat of evaporation,” which causes a great deal of heat to be used in the evaporation of water and thus cools the surface of the body when we perspire.

We have already mentioned the transportation of water in plants, but one way in which this is accomplished is interesting.

Water has a strong attraction for itself; it “sticks to itself,” which we call cohesion.

It also sticks to other things, and we call that adhesion.

This latter property of water is very important.

Because water can stick to other substances it can actually “climb” up in a small tube.

This is known as capillary action and is the main means of transportation in plants.

The water enters the plant from the ground and must climb up the tree, carrying with it the dissolved substances that the plant needs for life.

Actually, this process depends upon both the cohesion in the liquid itself and the adhesion to the walls of the small veins inside the plant.

How powerful is this force?

It is known that in some trees a water column of 430 feet in height can be supported by this powerful “sticking” force of water.

Water inside living things enters into many of life’s chemical processes.

Many compounds can be split by water to form others and thus carry on the chemical work of the organism.

Cane sugar, for example, is split into equal parts of glucose and fruit sugar, one water molecule being used up in the process.

Of even greater importance to life is the splitting by water of some of the phosphate compounds.

This process releases energy, which then can be used by the body for the building up of other vital compounds.

In plants, too, water plays a. chemical role in the photosynthesis process.

Sunlight on the green plant causes oxygen to be released from the water and causes the hydrogen atoms left over to be utilized, along with carbon dioxide, in such a way as to form sugar.

Ice and steam

Picture of ice melting into water vapor.

A discussion of water’s properties would not be complete without a word about its many applications and its usefulness in the solid state as ice and also as water vapor(steam).

Water is unusual in that it reaches its most dense point before it becomes a solid.

How is this important to us?

If water gradually became more dense with the lowering of the temperature, as do most substances, it would solidify in such a way as to be a real problem for mankind.

Actually, water reaches its most dense point at 4 degrees above its freezing point or at 4 degrees Centigrade.

This means that when a large body of water, such as a lake, cools from the cold air above it, the surface water becomes cold first and grows heavier.

It sinks to the bottom of the lake, and the warmer water rises.

In this way the entire body of water cools at the same rate.

Finally, the surface water falls below 4 degrees Centigrade and the water turns to ice, which is lighter than the dense water below it and so does not sink, but, instead, floats on the surface.

Therefore instead of having the bottom freeze first, and thereby eventually filling up the lake with ice and killing all water life, a thin crust of ice forms on the surface and prevents the rest of the water in the lake from becoming cold enough to freeze.

One of the principal uses of water in industry is to generate power through steam, water in the vaporous form.

Water has the ability, when changing from ice to liquid to steam, to “store up" heat and hold it without itself rising in temperature.

What an amazing substance water is!

Every day of our lives we see water working for us, in the plants we must have for food, in our own body chemistry to keep us healthy and in the practical uses we find for it to help us do our work.

Systems have been devised that allow space explorers to orbit the earth in outer space, but scientists know that, unless they can solve the problem of providing sufficient water, the human race is bound to this earth by its need for abundant water in order to maintain life.

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