ALEX Lesson Plan

The student engineers will design and build 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. 

Students will be involved in planning, designing, building, collaborating, calculating, budgeting, analyzing, and reflecting on a real-world design challenge. 

This lesson was created as part of the 2016 NASA STEM Standards of Practice Project, a collaboration between the Alabama State Department of Education and NASA Marshall Space Flight Center.

Student Materials (Group of 4):

• the bottom half of a 2-liter bottle 
• 2 cups of water per group of 4
• 2 clear plastic cups (1 labeled "Before" and 1 labeled "After") 

Student Handouts

• It's Crystal Clear! Planning Guide
• It's Crystal Clear! Experiment and Record
• It's Crystal Clear! Data Analysis 
• It's Crystal Clear! Quality Assurance Form

Teacher Materials

• Town Hall Meeting Guidelines (Extension)
• Prompts to Extend a Conversation (Extension)
• Recipe for Polluted Water 
• a table or space labeled with group number cards to identify a place for each group's final product comparison

Student Choice Materials

• coffee filters 
• top soil 
• sand 
• cotton balls
• window screening (pre-cut into 6X6 squares)
• activated charcoal - You may want to pre-rinse before allowing students to use.
• cheesecloth
• pea gravel 
• dried elbow pasta 
• any material that could be used a filtering agent

• Projector system
• NASA's website: Climate Kids: NASA's Eyes on Earth - Gallery of Freshwater
• NASA's Water for the World video
• Stopwatch or other timing device 

Prior to the Activity

• Students should be able to identify the causes and effects of pollution on our water systems.  Show and discuss the Water Filtration PowerPoint presentation included in the Attachments section.
• Students should be able to identify the steps of water treatment and distribution to homes. 
• Students should have viewed the NASA siteClimate Kids: NASA's Eyes on Earth to gather a clear visual understanding of the impact of pollution on our planet.
• Students will gain background knowledge before the design challenge is completed using the Pre-Lesson to Water Filtration System activities included in the Attachments section.
• Have students read the NASA article Space Radar Helps Track Underground Water Pollution Risks to provide additional background information.

Teacher Facilitated: 

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)

Student Facilitated:

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: 

• sand
• gravel
• cotton balls
• screen
• activated charcoal or carbon
• soil

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)

Teacher Facilitated: 

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)

Students will write a reflection by answering the following:

• What is the most effective process for cleaning a polluted environment? 

Students will need to answer the question focusing back on the objectives (targets) from the beginning of the lesson: 

• Explain the water filtration system process with emphasis on potability. 
• Demonstrate an understanding of the cause and effect relationship between human responsibility and environmental pollution.
• Describe the steps to engineering a water filtration system with the focus on potability.  

The engineering group that meets the challenge of designing the cleanest system will present the design through a town hall simulation. Collectively, the town will create a mitigation plan to ensure potable water is available to the community. The engineering group will collaborate with the "community" (students who did not meet the challenge) to generate a mitigation plan to lessen the chances of polluting the community's water source again. 

Students can compare this engineering challenge to the process that the International Space Station has in place to purify recycled water for the astronauts. Students can read about the Environmental Control and Life Support System (ECLSS), built in Huntsville, by reading the article Water on the Space Station.

Students can "purchase" items to use in their filter within a given budget.  Not only will students focus on generating the cleanest water, they will focus on spending the least amount of money to create the most cost-efficient filtering system.   

• Strategic partnering 
• Visual clock available to keep students on task
• Peer tutoring - have higher achieving students assist with those students who need extra guidance.
• The teacher may pull a small group to assist through the lab to guide through the steps.