1. To gain a visual image of the importance of today's challenge, have students view "NASA's Water for the World" clip. (Time 3:32)
2. Quickly review the prior knowledge on the steps in the water treatment process including aeration, coagulation, sedimentation filtration and disinfecting. What is the purpose of each step in creating potable water? (5 minutes)
1. Scenario: You and your team of engineers are challenged with the task of designing and building a new water filtration system for an overpopulated, poverty-stricken community that is drinking contaminated water from wells, rivers or springs not treated by municipal water systems.
Can your team rise to the challenge to help this community have safe drinking water for generations to come?
2. Assign roles in your group.
- Timekeeper- Keeps time and gives frequent reminders on remaining time
- Materials Manager- Gather all materials for group
- Clean Up Manager- Delegates jobs for all group members to assist in clean up
- Procedures Manager- Responsible for reading each step below and keeping the team on track with the challenge
*** Everyone will have a role in the construction of the filter.
3. Using the It’s Crystal Clear! Design Planning sheet, have a discussion as a team while each member records on their paper. The timekeeper should start the clock for 10 minutes.
4. Your group will have the choice of using the following materials:
- cotton balls
- activated charcoal or carbon
Your challenge is to work as engineers to build a filter that effectively creates the cleanest water. We are looking for clarity and the lowest amount of DOM (Dissolved Organic Matter).
5. Brainstorm and sketch your filter design on your worksheet. Your sketch should show the various layers of materials you are going to use. Be sure to include labels.
6. Have your materials manager gather all materials.
- 1 half of a two-liter bottle (required)
- 1 baggie of dirty water with high DOM (required)
Be careful not to shake it up!
- 2 clear plastic cups (required)
- One is labeled “Before,” which will hold a sampling of your “polluted” water.
- The other is labeled “After,” which will hold your “filtered” water.
- Any materials from the available choices to be used as filtering agent
7. Begin constructing your filter as a team. The timekeeper starts the timer for 30 minutes.
8. Pour a sampling of the “polluted” water in the cup labeled “Before” and hold aside for later.
9. Once you have completed the construction, run the water through your filter three times, each time moving the filtering apparatus onto the empty cup and pouring the excess water on top of the filter.
10. You should be able to see a difference between your initial water sample and the final product. Think about how well your filter worked. Would you drink this water?
11. If time allows, redesign your filter based on what you've learned so far. Then, filter your cleaner water you’ve improved with the filtering apparatus two times. Now, you should have your final product.
12. Make observations about your filtered water and record on It’s Crystal Clear! Experiment and Record sheet.
13. Finally, you and your team will compare final products between groups and think about why some designs worked better than others. Have your materials manager place your original polluted water (labeled “BEFORE”) from the beginning next to the final filtered cup of water (labeled “AFTER”) on the table by your group number.
14. Each member of the group will record data on the final products of other teams on the It’s Crystal Clear! Data Analysis sheet. The timekeeper starts the timer for 10 minutes.
15. If time allows, the It’s Crystal Clear! Quality Assurance Form can be filled out by teams to give feedback to other teams. (5-6 minutes)
1. Come together as a whole group to discuss who met the challenge of creating the cleanest water (clarity and least amount of DOM). Have them share out what materials were used and why and the design. (5 minutes)
2. Before time is up, have students generate a quick-write summary of the challenge. (20 minutes or can be completed for homework)