1. SOLAR STILL ANNA VAZQUEZ, UMAIR MUHAMMAD, ORIOL FERNANDEZ, MARC CARAVACA

2. INTRODUCTION Did you know that water covers about 70% of the Earth? But almost all of it is in the oceans and undrinkable.

3. INTRODUCTION The solar still uses solar energy to purify water.

4. EQUIPMENT Plastic Bowl Evaporating Dish Salt Cling Film Small Stone A Beaker with Hot Water Food Dye

5. PROCEDURE 1 st We add some food coloring and a teaspoon of salt.

6. PROCEDURE 2 nd We then put the cup in the middle of the bowl.

7. PROCEDURE 3 rd We add the hot water to the bowl until it is about one centimeter full.

8. PROCEDURE 4 th Then we’ll cover the bowl loosely with cling film, sealing the film to the rim of the bowl. You can use tape or string to do this if necessary.

9. PROCEDURE 5 th Now we’ll take the equipment out to a sunny, level place. 6 th Next we’re going to place the stone on top of the film, in the middle above the cup. 7 th Now we’re ready to leave the still for at least an hour, the longer the better.

10. PROCEDURE 8 th Then we’ll check to see if there is some water in the cup. 9 th When we have some water in the cup, we’ll take the still back indoors and remove the cling film. 10 th Then we’ll take out the cup without splashing any water into or out of the cup. 11 th Now we measure the amount of water in the cup and observe the color of the water in it and test it for salt.

11. PROCEDURE Volume collected in the evaporating dish ÷ Total volume X 100 = The percentage of purified water 40 ml ÷ 500 ml X 100 = 8% 12 th Here is how we then calculate the percentage of the water that was purified: 13 th Lastly, we observe our results and see if we can explain what happened to the water.

12. CONCLUSION Now you may be wondering why it is called “purified water”. Well, what ideas do you have? Tell me.

13. THANKS FOR YOUR ATTENTION