The Water cycle starts with the evaporation of water from the sea under sunlight or warm air. The moisture contained in the air rises to form clouds. As the wind blows the clouds over land the clouds rise and cool down. Cool air holds less moisture than warm air and so precipitation takes place and the water falls as rain onto the land. The water drains along the surface of the land as well as underground into rivers and eventually back into the sea.

The cycle starts all over again.

1. Visit a water purification plant to find out how our water is filtered and treated to make it safe for drinking.
   1. How clean is the water when it leaves the plant?
   2. Has the water undergone
      • mechanical treatment?
      • biologoical treatment?
      • chemical treatment?
      • further treatment
   3. Where is the purified water discharged?
   4. What happens to the sludge that remains after the purification process?
   5. What method is used for bilogical treatment?
   6. Are there households or industries in your community that are not connected to the plant? Where is their sewage water discharged?
2. Find out what dangers exist from drinking fresh, flowing water in the countryside. Are all the Scouts in your Patrol aware of the dangers and prepared to take the necessary precautions?
3. In Patrols discuss what precautions should be taken at camp to make sure your water stays clean and fit for drinking.

 

	Experiment 1 On a sunny summers day a big birch tree can give off as much as 450 litres of water through evaporation. Take a glass, put it upside down on some grass in the sunshine. After a while you will notice how water, evaporating from the soil and the grass, condenses to form water drops on the inside of the glass..
	Experiment 2 Water a potted plant. Put a plastic bag over it and place it in the sun. Soon afterwards, you will find small drops of water on the inside of the bag.TD>
	Experiment 3 Fill three bottles with an equal amount of water. In the first bottle put a branch with no leaves; in the second, a branch with a few leaves; in the third, a branch with a lot of leaves. Put some oil on the water surface in each bottle to prevent evaporation. After a few days, measure the water in each bottle. You will find that most of the water has gone from the third bottle. Why is this so?