1. Water Treatment

2. What is the chemical formula for water?? H 2 O What do these letters mean? (Look at the periodic table) H = Hydrogen O = Oxygen Water is 2 Hydrogens (H 2 ) bonded to 1 Oxygen (O)

3. Is water a compound or an element?? Remember to test for water COBALT CHLORIDE PAPER is used it turns from blue to pink if water is present Test this in class

4. The Hoffman Voltameter We can use this to prove that water is made of Hydrogen and oxygen

5. What exactly is happening??

6. Properties of Water Freezing point of 0°C Boiling point of 100°C What do you think would happen if a bottle full to the brim with water was frozen? Water expands when it freezes this is why bottles and pipes burst in cold weather!

7. An unusual fact Ice floats on water because it is less dense than water This is why fish and other organisms can survive in a lake as the top freezes over but because this floats on the surface life can continue underneath!

8. Water as a Solvent What does dissolved mean? Do you think water is a good solvent?

9. Experiment

10. What kinds of things might be in water that we can’t see? Chemicals Bacteria Viruses Salt Poisons Toxins

11. How do we make sure our water is clean?

12. It is important to understand what each of these stages involves

13. Watch the following video clip from Unicef C:\Documents and Settings\Laptop\Desktop\Carol School Work\UNICEFWatertreatment.gvpC:\Documents and Settings\Laptop\Desktop\Carol School Work\UNICEFWatertreatment.gvp

14. 2 nd watch with questions!! 1.What is a big problem in this area? 2.What stage of water treatment is being used? 3.Why is this stage being used? 4.How many people drink this water? 5.What happened to the 20 month old baby? 6.How is further prevention being carried out?

15. Are there harmless things dissolved in water??

16. How do calcium ions get into the water??

17. As we can see from the water cycle the water falls as rain back to earth and then drains into rivers, lakes and oceans If the rain flows through a limestone region (such as the Burren) it can dissolve the calcium in the rock and become “hard” NB Hard water is not ice!!

18. What does hard water mean??

19. Experiment to test water samples for hardness

20. You can easily do this at home by mixing soap with your water and seeing if it will form a lather or not!!

21. There are disadvantages and advantages to having hard water can you think of any??

23. Do you think it is possible to remove “hardness” from water??

25. Summary