1. The Water Cycle: PBL Task

2. Must… Find… Water…

3. You and your team have been left on deserted island somewhere off the coast of South America. You to evaluate your situation and prioritize what your most important needs are. The Scenario:

4. Things Just Got Worse: Something you should know about your environment: There is no source of fresh water on the island & it is the dry season (no rain) on the island.

5. What do we know about what humans need to survive? What do we need to know water? What do we need to do to find a solution to this problem? Background Knowledge to Assist You: (Copy into your Science Notebook)

6. Problem Statement Model How can we __________________________ In such a way_________________________ Example Problem Statement: How can we design a method to get freshwater from saltwater… …In such a way that provides us with water without the salt?

7. You have no supplies…. But you find 1 backpack that has drifted up on shore! Inside the pack are the following materials: A tin can A large clear bowl A black plastic bag Clear plastic wrap A rock A roll of tape A large piece of tin foil

8. Challenge! You and your team need to act fast. You need Clean, Fresh Water! What Luck! One of the members of your group has just finished studying the water cycle and has an idea that just might work! Challenge: Using the materials in the backpack, You must develop a “water purification system” to clean the salt water & be sure no bacteria is in the water you drink…Time is running out…

9. Why can’t humans drink salt water?

10. What are the possible solutions?

11. Present Your Solution

12. Time To Debrief!

13. Evaporation: Water is heated and changes to water vapor/gas Sediments and bacteria are left behind. Water vapor cools as it sticks to plastic wrap & begins to form water droplets : Condensation Water becomes too heavy and falls as precipitation (clean water) Metal cup acts as water collection for water (like a lake/ocean/stream R.I.P. or sittin’ pretty sippin’ some cool, clean water in the sunshine? (Possible Solution)