Total Duration: |
61 to 90 Minutes |
Materials and Resources: |
Materials Needed:
Gather enough for multiple groups to use 7 different materials for filtration layers
Contaminated Water Ingredients Instructions for making wastewater can be found on pages 12 and 13 of the Education Guide. Italian salad dressing could be substituted for the contaminated water as well.
Materials needed per group (3–4 students working together)
Per student
Safety Remind students about the importance of classroom and lab safety. Review the rules for smelling (wafting) in the science lab. Students should wear eye protection during this activity. |
Technology Resources Needed: |
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Background/Preparation: |
At least one day before conducting this experiment:
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Pre-lesson Instructions (30 minutes prep time) • Students should work in groups of 3 or 4. • Write the names of the 7 different filtering materials on 7 individual small slips of paper and place them in a hat or basket. In addition, write “free choice” on several small slips of paper. Add enough “free choice” slips for each group to choose a total of 3 filtering materials (suggested option). You may also place the materials as a "store" and students have a certain price range they can use for the store. • Gather materials for this activity. Each filtration material needs to fill the water filtering system to a depth of 5–8 cm. There should be enough of each filtration material for several groups to use. Make sure to have extra material for students to chose their “free choice” options. • Wad up enough coffee filters for multiple groups to use as a filtration layer (You may leave this out and have the filters in the store setting making them develop this strategy on their own). • Rinse the activated charcoal granules in advance to remove the dust. Put the granules in a mesh bag (panty hoses works well) and rinse with tap water. Note: To increase rigor, you may give them the contaminated water and bottle filter base. All other materials will be used by each determining group. This allows for higher thinking and creative skills. Filtering system structure: (one per group)
To increase rigor, you may allow the students to determine how to place and use the filter design in their groups independently. Make “Contaminated Water”:
Note: Reserve enough clean water (either tap water or store-bought drinking water with a pH between 6.5 and 7.5) so that each student group has about 500 ml. Instructional Procedure 1. Show NASA’s 21st Century Explorer Newsbreak video “Where Would a Space Explorer Find Water and Oxygen?” (see right sidebar on website) to engage students and increase student knowledge about this topic. 2. Remind students about pH including base, neutral, and acid. Also reference pH testing using litmus paper and pH color charts. 3. Review the problem with the students. 4. Pass out a copy of Observation and have the students read and discuss in their groups. 5. Encourage your students to discuss and make observations about this topic by completing the first two columns in the KWL (KNOW/WANT TO KNOW/LEARNED) chart in their journals. Use the KWL chart to help students organize prior knowledge, identify interests, and make real-world connections. As students suggest information for the “KNOW” column, ask them to share “How they have come to know this information.” 6. Allow your student groups time to develop a Hypothesis relating to this activity and the “problem question."
Students 1. Put on your safety glasses. 2. Place the bottle upside down with its mouth over the clear plastic cup to catch the filtered water. Make sure the cup underneath the system is large enough to “catch” the water to be filtered through. 3. Choose three slips of paper from the teacher. The items written on these papers will be the materials you layer in your water filter. If you choose a “free choice” slip, you and your group may choose what material to use for OR Give students an objective: Their town's water supply is contaminated after a storm. It is their mission to develop a filtration system. The filter must be able to allow water to run through and deposit into the cup. Note: This is where you may limit direct instruction and allow creativity. You may also allow the "store" concept to replace the above distribution technique. Students 4. Gather your filtration materials on the paper plates; one on each plate. As a group, decide the order in which to layer your materials. 5. Fill the bottle with the first filtering material to a depth of 5–8 centimeters (cm). 6. Place the second filtering material to a depth of 5–8 cm on top of the first one. 7. Place the third filtering material to a depth of 5–8 cm on top of the second filtering 8. Obtain 350 ml of clean water. Observe the properties of the water before you filter it. Use the wafting technique to smell the water. Measure the pH of the water with litmus paper and compare it to the pH color chart. Collect data and record your observations. Remember smelling rules in the science lab and do not taste. This pH measurement will serve as the control. Note: When filtering the contaminated water, students will know the contaminated water is cleaned when it matches the control pH. 9. Run the clean water through your water filtering system to make sure it will allow water to flow through. Students should run approximately 10-16 oz. of clean water through their water filtering system to make sure it will allow water to flow through. Make sure the cup underneath the system is large enough to “catch” all the water passing through. OR Allow students to experiment and determine if their design will work. 10. While you are waiting for the clean water to run through the water filtering system, draw and label your diagram to match your filtration system. (this can be skipped and allow students to work without determining if the filter works) 12. Get 350 ml of contaminated water. Observe the properties of the water before you filter it. Check the odor of the water. Measure the pH of the water with litmus paper and compare it to the pH color chart. Collect data and record your observations. 13. Run the contaminated water through your water filtering system. Observe the properties of the water after it has been filtered once and record your observation.
14. Replace the clear plastic cup with a new one. Pour the filtered water back into the water filtering system. 15. Filter the water again. While the contaminated water is running through the water filtering system, discuss in your group what each layer in your filtration system did to the water. 16. Observe the properties of the water after it has been filtered for the second time. Check the odor of the water. Measure the pH of the water with litmus paper and compare it to the pH color chart. Collect data and record your observations. Remind students the rules of the science lab regarding smelling and tasting. 17. After taking all measurements, study the data and draw conclusions by answering the questions. Make sure the students compare the properties of their filtered water to the control (clean water) to determine if their contaminated water was “cleaned” by their water filtering system. Using this information, ask students to determine if the data supports or refutes their hypothesis. 18. Dispose of all material by wrapping in newspaper and placing the material in a trash receptacle. Conclusion |
Assessment Strategies |
Assess student knowledge through summative questioning. Some sample summative guidelines for questioning:
Observe and assess student performance throughout the activity using the attached Scientific Investigation Rubric. You may also use the activity rubric to grade this activity with or without journal entry. |
Acceleration: |
Collect and filter other samples of water. Examples are rain water, hand wash water, stream or pond water, etc. * Use the Design Evaluation Sheet that includes conductivity |
Intervention: |
Students who need extra support should be placed in groups with teammates sensitive to the needs of that student. The teacher may need to more closely supervise groups that contain students who are struggling with the concepts of this lesson. |
View the Special Education resources for
instructional guidance in providing modifications and adaptations
for students with significant cognitive disabilities who qualify for the Alabama Alternate Assessment.
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