Choose one of the following topics for your presentation:

1.Water-movement in sea in comparison with water-movement in rivers

 

- tides, waves, currents, flowing water, water-speed in rivers, …

 

2.Chemical composition of sea water versus river water

 

• Why is sea-water salty? why is river-water also called "sweet water"?

 

3. Lime in water

- appearence, frequency

- calcification

 

4. Water as a habitat for people

 

5. Pollution of water by agriculture (nitrates)

 

6. River zonings

- flora and fauna in the different zones

 

7. Water Sports

 

8. Drinking Water

- sources (tap, bottles, ...)

- price, origin

          9. Salt Lakes