WHY IS WATER SO WHY IS WATER SO IMPORTANTIMPORTANT ? ?

There are various theories There are various theories about origin of water onabout origin of water onthe Earth.the Earth.

For example, scientists suggestFor example, scientists suggestthat early Earth hadthat early Earth had a thicka thickhydrogen atmosphere, which hydrogen atmosphere, which interacted with the oxygen ininteracted with the oxygen inthe structure of the planet,the structure of the planet,with the resultwith the result the waterthe waterwas formed. was formed.

Water is the chemical substance with Water is the chemical substance with chemical formula H2O: one molecule chemical formula H2O: one molecule of water has two hydrogen atoms of water has two hydrogen atoms covalently bonded to a single oxygen covalently bonded to a single oxygen atom.atom.

((Model of hydrogen Model of hydrogen bonds between bonds between molecules of watermolecules of water))

Water appears in nature in all three common states Water appears in nature in all three common states of matter and may take many different forms on of matter and may take many different forms on Earth: water vapor and clouds in the sky; seawater Earth: water vapor and clouds in the sky; seawater and icebergs in the polar oceans; glaciers and rivers and icebergs in the polar oceans; glaciers and rivers in the mountains; and the liquid in aquifers in the in the mountains; and the liquid in aquifers in the ground.ground.

The major chemical and The major chemical and physical properties of water physical properties of water are:are:• Water is a tasteless, odorless liquid at standard temperature and Water is a tasteless, odorless liquid at standard temperature and

pressure. The color of water and ice is, intrinsically, a very slight blue pressure. The color of water and ice is, intrinsically, a very slight blue hue, although water appears colorless in small quantities. hue, although water appears colorless in small quantities.

• Water is transparent, and thus aquatic plants can live within the water Water is transparent, and thus aquatic plants can live within the water because sunlight can reach them. Only strong UV light is slightly because sunlight can reach them. Only strong UV light is slightly absorbed.absorbed.

• Since the water molecule is not linear and the oxygen atom has Since the water molecule is not linear and the oxygen atom has a higher electronegativity than hydrogen atoms, it carries a a higher electronegativity than hydrogen atoms, it carries a slight negative charge, whereas the hydrogen atoms are slight negative charge, whereas the hydrogen atoms are slightly positive. As a result, water is a polar molecule with an slightly positive. As a result, water is a polar molecule with an electrical dipole moment. electrical dipole moment.

• Water is a good solvent and is often referred to as the universal Water is a good solvent and is often referred to as the universal solvent. solvent.

• Pure water has a low electrical conductivity, but this increases Pure water has a low electrical conductivity, but this increases significantly with the dissolution of a small amount of ionic significantly with the dissolution of a small amount of ionic material such as sodium chloride.material such as sodium chloride.

Water covers 71% of theWater covers 71% of theEarth's surface; the oceans Earth's surface; the oceans contain 97.2% of the Earth'scontain 97.2% of the Earth'swater. The Antarctic ice sheet,water. The Antarctic ice sheet,which contains 90% of allwhich contains 90% of allfresh water on Earthfresh water on Earth,,isisvisible at the bottom.visible at the bottom.Condensed atmosphericCondensed atmosphericwater can be seen as clouds,water can be seen as clouds,contributing to the Earth'scontributing to the Earth'salbedo.albedo.

From a biological standpoint, water has many distinctFrom a biological standpoint, water has many distinct properties that are properties that are critical for the proliferation of life that set it apart from other substances. It critical for the proliferation of life that set it apart from other substances. It carries outcarries out this role by allowing organic compounds to react in ways that this role by allowing organic compounds to react in ways that

ultimately allow replication. ultimately allow replication. All known forms of life depend on All known forms of life depend on water. water.

People can’t livePeople can’t live without without water.water.Water balance is crucial for the Water balance is crucial for the whole organism.whole organism.

Human usesHuman uses• AgricultureAgriculture ( (Irrigation of field cropsIrrigation of field crops))• Water as a scientific standardWater as a scientific standard• HygieneHygiene• For drinkingFor drinking• Ice used for coolingIce used for cooling• Water is used for fighting wildfiresWater is used for fighting wildfires• Water sport (recreation)Water sport (recreation)• Water industryWater industry• Water is used in power generationWater is used in power generation• Water can be used to cook foodsWater can be used to cook foods• Water plays many critical roles within the field of food Water plays many critical roles within the field of food

sciencescience• Water is used for dishwashingWater is used for dishwashing• etc.etc.

Water, for cookingWater, for cooking

Water, for Water, for cleaningcleaning

Water, for Water, for drinkingdrinking

Water, for livingWater, for living

Water, for dying.Water, for dying.

Water is an essential ingredient Water is an essential ingredient of all living cells. Water helps a of all living cells. Water helps a plant by transporting important plant by transporting important nutrients through the plant. nutrients through the plant. Nutrients are drawn from the soil Nutrients are drawn from the soil and used by the plant. Without and used by the plant. Without enough water in the cells, the plants enough water in the cells, the plants droop, so water helps a plant stand. droop, so water helps a plant stand. Water carries the dissolved sugar and Water carries the dissolved sugar and other nutrients through the plant. So other nutrients through the plant. So without the proper balance of water, without the proper balance of water, the plant not only is malnourished, but the plant not only is malnourished, but it is also physically weak and cannot it is also physically weak and cannot support its own weight.support its own weight.

Water makes up the majority of an animals’ body throughout growth and development. Animals gain water from the food they eat, from oxidation of fats and proteins in the body, and from the action of drinking water from a source such as a river or lake. Properties of water may help to normalize bodily functions such as regulation of body temperature, body weight, and also becomes a factor in determining health (losing one tenth of the body’s water results in death, for example).

By means of By means of water, we give life water, we give life to everything.to everything. KoranKoran

Water, water everywhere, water all Water, water everywhere, water all around, around, Water in the ocean, water in the ground.Water in the ocean, water in the ground.

Water in a river, water in a creek, Water in a river, water in a creek, Water in a faucet with a drip-drip leak! Water in a faucet with a drip-drip leak!

Water in a fountain, water in a lake, Water in a fountain, water in a lake, Water on a flower, as day begins to Water on a flower, as day begins to break.break.

Water from a waterfall, rushing down Water from a waterfall, rushing down from high, from high, Water from a dark cloud, raining from Water from a dark cloud, raining from the sky.the sky.

Water boiling hot, water frozen ice, Water boiling hot, water frozen ice, Water in a blue lagoon, clean and clear Water in a blue lagoon, clean and clear and nice.and nice.

Water at a fire, gushing through a hose, Water at a fire, gushing through a hose, Water in a garden, so every flower Water in a garden, so every flower grows.grows.

Water for the animals swimming in the Water for the animals swimming in the sea, sea, Water, water everywhere for you and for Water, water everywhere for you and for me! me!

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