2.The light water vapour rises, cools and condenses into tiny droplets which make up cloud.
3.Further cooling and condensation results in precipitation.
4.Surface run-off(rivers) and soakage returns most of the water to the sea ( some water is evaporated immediately back into atmosphere
And the whole cycle beings again
Importance of Water
- The plants that provide us with food need water to grow. Farm animals need water and plants in order to survive
- We each need an average of litres of water a day just for drinking and cooking
- It is estimated that ¾ of all diseases in the 3rd world are related to a lack of clean water and sanitation.
- In the Sahel region of Africa drought and desertification are resulting in terrible suffering.
- A person can survive only a few days without water
- A toilet flush uses up to 10 litres of water
- Farmers in dry regions often use irrigation to increase yields from their land.
Polluting our Water Supplies
- The overuse of fertilisers sometimes results in too many nitrates and phosphates entering rivers and lakes.
- This causes the rapid growth of weed-like algae. The algae can use up so much of the water’s oxygen supply that fish and other water creatures die
- Untreated household sewage can pollute water and harm human health. In 2007 up to 210 Galway people became ill when human sewage polluted their water supply
- Chemical or industrial waste can pollute water and poison fish life. People who eat fish that have been affected by pollution can also be poisoned.