Evaporation occurs when the sun heats up water in rivers, lakes, oceans, trees and plants and turns it into water vapour.
2. Condensation
The water vapour rises into the air. As the air rises, it cools. The water vapour condenses into tiny droplets which come together to form a cloud. The wind blows these clouds towards the land. 3. Precipitation
Precipitation occurs when so much water has condensed that the air cannot hold it any more. The clouds get heavy and water falls back to the Earth in the form of rain, hail, dew, sleet or snow.
4. Run-off
When the water falls back to Earth as precipitation, it may fall back into the oceans, lakes or rivers or it may end up on land. When it ends up on land, it will either soak into the soil and become part of the groundwater that plants and animals use to drink or it may run off the soil into oceans, lakes or rivers where the cycle starts all over again.
Water in Ireland ACT VITY
Divide up into groups of four and answer the following questions: (a) How does water end up in our taps? (b) Where does the waste water from our homes go?
Irish Water is responsible for the public water supply in Ireland. It is also responsible for looking after Ireland’s waste water.
( Figure 4.3 Vartry reservoir, near Roundwood, Co. Wicklow
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Primary Economic Activities: How we use the world’s natural resources
