Engineering Air Purifiers
Students apply the engineering design process to design, build, test, and optimize Corsi-Rosenthal box air purifiers—real devices that effectively clean indoor air.
9
Lessons
10-12
Class Periods
$60-100
Per CR Box
4
NGSS Standards
Essential Question
How can we use engineering design to create effective, affordable solutions for improving indoor air quality?
Lessons
-
1→Why Clean Air Matters
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2→The Science of Filtration
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3→Meet the CR Box
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4→Engineering Design Process
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5→Building Our CR Boxes
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6→Testing & Data Collection
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7→Analyzing Results
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8→Design Challenge
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9→Presentations & Reflection
Materials
Per CR Box (groups of 3-4 students)
| Item | Quantity | Est. Cost | Notes |
|---|---|---|---|
| 20" box fan | 1 | $20-25 | Multiple speeds preferred |
| 20"×20"×2" MERV-13 filters | 4-5 | $10-15 each | MERV-11 as budget option |
| Cardboard (20"×20") | 1 piece | $0-2 | For top of cube |
| Duct tape | 1 roll | $5 | Per class, shared |
For Testing (shared classroom set)
| Item | Quantity | Notes |
|---|---|---|
| PM2.5 sensor | 1-3 | PurpleAir, Temtop, or similar |
| Timer/stopwatch | 3-4 | Phone timers work |
| Incense or candles | 1 pack | For particle generation (teacher use) |
Budget Alternative: Single-filter design (~$30 total) using one filter taped to fan face. Less effective but functional for demonstrations.
Standards Alignment
NGSS Performance Expectations
| Standard | Description |
|---|---|
| MS-ETS1-1 | Define criteria and constraints of a design problem |
| MS-ETS1-2 | Evaluate competing design solutions using a systematic process |
| MS-ETS1-3 | Analyze data from tests to determine similarities and differences among solutions |
| MS-ETS1-4 | Develop a model to generate data for iterative testing |
CCSS-M Mathematical Standards
| Standard | Application |
|---|---|
| 7.G.B.6 | Box dimensions, filter surface area |
| 8.EE.B.5 | CADR vs. fan speed relationships |
| 7.RP.A.1 | CFM and ACH calculations |
| 6.SP.B.4 | Graphing test results |
Assessments
Performance Task
Design Challenge: Optimize a CR box for a specific scenario (school nurse's office, art classroom, wildfire shelter, or home bedroom).
View TaskUnit Quiz
30-point assessment covering filtration science, CADR calculations, and engineering design process.
View QuizFormative Assessments
- Exit tickets (each lesson)
- Engineering journal documentation
- Build quality checklist
- Peer feedback sessions
- Data collection accuracy