Water in Nature
The Water Cycle
There is always the same amount of water in the World. The water gets used all the time, but it never gets used up! This is because it is always being recycled. It goes round and round in the Water Cycle, powered by the sun.
We usually think of water as being liquid – the splashy form we drink or swim in, but it also comes in two other forms – solid and gas. Ice is the solid form of water. To make liquid water turn to solid ice we cool it until it freezes.
To turn it into ‘water gas’ – otherwise called water vapour - we warm liquid water!
When the sun’s energy falls on liquid water it excites all the tiny water particles and some of them leap into the air to become invisible water vapour! This is called evaporation.
The vapour rises up into the sky where it cools. The particles join together to make a fine mist of liquid water again, high in the sky. This is a cloud, which we can see! When the particles get too big to float in the sky they turn into drops of rain which fall to the ground. This is called precipitation. The water sometimes comes down as snow, hail or sleet.
The water can do a number of things:
Water is able to pass through the ground through spaces between individual grains of some types of rock and by squeezing through cracks. Rocks which allow water to pass through them are permeable, e.g. sandstone.
Rocks which do not allow water to pass through them are impermeable, e.g. granite.
Some permeable rocks hold water in tiny pores like a sponge, e.g. chalk. When the pores of a rock are full of water the rock is saturated. These water-filled rocks are called aquifers and they are important because we can drill down into the aquifer and pump out the water. The hole which is dug is called a borehole.
©2006 Anglian Water Services Ltd