Why Is Water Important?
It’s common to hear that water is essential to us. But why is water important?. All living things need water for their survival but water is used not only for survival. Today we will discuss
From industry to agriculture to generating power for factories and homes, we make water work for us. To make the paper for this book, about 18 litres of water were used, and other industrial processes, such as making cars, use vast amounts of water. Some power stations use water to generate electricity, while others need large quantities of water to cool machinery – you can often see water vapour escaping into the atmosphere through huge cooling towers.
Water generates power when it flows from a higher to a lower place. Waterwheels were originally used to capture the energy of flowing water and use it to turn millstones that ground corn or wheat to generate electricity. Modern turbines are huge machines weighing thousands of tonnes. They are usually placed at the bottom of a
dam to make the best use of the energy made by falling water.
In the USA, industry uses around 1,450 million litres of water each day. Water is used for washing, cleaning, cooling, dissolving substances and even for transporting materials, such as logs for the timber industry. About 32,200 litres of water are needed to make a car and nine litres of water are used to produce just 1.2 litres of lemonade. The largest industrial users of water are paper, petroleum, chemicals, and the iron and steel-making industries.
Crop plants, such as wheat or rice, need large quantities of water to grow properly. In places where there is not enough water, or the supply varies with the seasons, farmers irrigate the land. Most irrigation systems involve a network of canals and ditches to carry water to the crops. The sprinkler irrigation system (below) has an engine and wheels and moves across a field spraying crops with a fine mist of water.
Flood irrigation is used to grow rice. The fields of young rice plants are flooded, covering them in water. These fields are called paddy fields (above). It takes about 4,500 kg of water to grow just 0.45 kg of rice. An Archimedes screw lifts water up a spiral screw to a higher level. The device was invented by the Greek scientist Archimedes over 2,000 years ago. It is still used in some parts of the world today.
Dams can cause problems for people and for the environment. Before a dam is built, people and animals have to be cleared from the area. If trees or plants are left to rot under the water, they make the water acidic and the acid may corrode (eat away) the machinery inside the dam. Reservoirs may become clogged by mud and silt which cannot be washed away downstream.
For centuries, salt has been a vital part of people’s diets and has even been used instead of money. In countries such as In China, India and France, salt is harvested from seawater and used for food flavouring or to make industrial chemicals. Seawater is left in shallow pools in the hot sun so that the water evaporates, or disappears, into the air. Salt crystals are left behind and can be raked by hand or collected by machines. The salt is then taken to a refinery where it is crushed, ground and sorted before being packaged and sold. Evaporating seawater is the oldest method of obtaining salt. This kind of salt is called solar salt.