Clean Water Engineers

Students in grades 5 to 7 spend nine class periods designing a low-cost filter that clears muddy creek water for a fictional village. They build a 0-to-5 clarity scale, build a filter from gravel, sand, charcoal, cotton, cloth, and coffee filters on a $20 budget, and find the flow rate in mL per minute and the cost per liter. The unit ends with a written report and a talk to the village water board, and every lesson teaches that the filtered water is never for drinking.

Driving question: How can we design a low-cost filter that turns muddy water clear, fast enough for a whole village to use?

What's in the PDF (23 pages)

• A teacher guide with the unit overview, the materials list, and 5 teacher tips
• 10 standards with what students do for each one, and a pacing table for all 9 days
• 9 lesson plans with minutes for each part, teacher notes, and an exit ticket
• 9 student handouts: Design brief: the Stony Ford water board, Clarity scale, Layer notes: what each layer catches, Filter plan and budget, Test log, Rates and cost per liter, Change order, Results graphs, Report to the water board
• A rubric with 4 rows and four score levels, and a student reflection page
• Support and extension ideas, and a plan for the final showcase

What students make

• A class clarity scale from 0 to 5, with labeled reference cups
• A filter plan and budget of $20 or less
• A test log for two versions of the filter
• Flow rate and cost per liter for both versions, with a class dot plot
• A written report and a three-minute talk to the water board

Day by day

Day 1, The water board letter: Students read the water board letter, learn how towns clean water, sign the safety rules, and sort the rules into criteria and constraints.

Day 2, How clear is clear?: The class mixes six reference cups of muddy water and builds a clarity scale from 0 to 5 with a printed card.

Day 3, Layers and a plan: Students watch a coffee filter and a sand filter work, learn what each layer catches, and plan and price a filter on a $20 budget.

Day 4, Build and test 1: Teams build version 1 of their filter and run the first test with 500 mL of muddy water.

Day 5, Rates and costs: Students find the flow rate in mL per minute and the cost per liter, and the class makes a dot plot of flow rates.

Day 6, Redesign one layer: Teams compare their results with the goals, change one layer, and rebuild the filter.

Day 7, Test 2: Teams test version 2, find the new rates and cost, and add their results to the class dot plot.

Day 8, Graphs and the report: Teams graph both tests and write a report to the water board.

Day 9, Water board meeting: Teams present to guests playing the water board, and each student writes a reflection.

Standards

• NGSS 5-ESS3-1: Students learn how towns use science to clean water and protect it.
• NGSS MS-ESS3-3: Students build a clarity scale and design a filter for muddy runoff.
• NGSS MS-ETS1-1: Students turn the water board letter into criteria and constraints.
• NGSS MS-ETS1-2: Teams compare filter designs against the criteria and choose one.
• NGSS MS-ETS1-3: Teams compare class test data to find the layers that work best.
• NGSS MS-ETS1-4: Teams test a model filter, change one layer, and test again.
• The other 4 standards are listed in the packet.

Printing

Print the teacher pages once for yourself, and print the handouts for each student or each team. The pacing table lists the handouts you need each day. Every page is Letter size, and the handouts print clearly in black and white.

License

This file is for one household, one classroom, or one homeschool group. You may copy it for your own students. An extra license is required before you share it beyond your group.

How you get your files
After checkout, the download link is on the order page and in your confirmation email. Open the PDF and print what you need.

Questions? support@trailposteducation.com