Grade 5 · Low-Tech Builds · Lesson 29

Stormwater Filter Model

Layer common materials to slow and clarify muddy model runoff.

Time2–3 × 60 minutesTeamsTeams of 3–4EquipmentNo powered equipment required

Project inspiration · 3 images

See, build, and test

Use these images to understand the kind of making, details, and testing involved. They are inspiration—not designs students must copy.

Finished student example for Stormwater Filter Model
01Finished project
Close construction and materials view for Stormwater Filter Model
02Construction detail
Students testing and recording results for Stormwater Filter Model
03Student testing

Student directions · Grade 5

What will you make and do?

You will build a layered filter model and compare how water moves through it. The result is an observation about flow and visible particles—not safe drinking water.

Teacher overview: Students will plan the specific object described below, make and test a first version, then use their results to improve it. Read one step together, demonstrate the unfamiliar action, and let students complete that step before moving on.

  1. 1Plan your project

    Look at the teacher-approved filter materials and predict which trap larger particles. Draw two layer orders and label the direction of flow.

  2. 2Make the first parts

    Use a teacher-prepared container with safe edges and a catch tray. Place the support layer and measured filter materials inside.

  3. 3Put it together

    Make a visible side diagram that matches the actual layers. Prepare equal portions of the teacher’s model dirty water; never use unknown outdoor contamination.

  4. 4Test it fairly

    Pour the same volume into each design. Time the flow and compare collected samples against the same white background without touching or tasting them.

  5. 5Improve one part

    Change one layer or its thickness, keeping water volume and other layers the same. Compare flow time and visible clarity again.

  6. 6Show and turn in

    Turn in the layer diagram, volumes, times and clarity observations. Label all samples NOT FOR DRINKING and explain that clear water can still be unsafe.

How will you know it works?

  • Water flows through the system
  • Output is visibly clearer than input
  • Layer diagram accurately explains the design

Before you move on

Explain which measurement, input or design choice you are testing. Predict the result and record what stays the same so your comparison is fair.

Machine cutting, printer setup and electrical power-on require adult approval. A basic-materials model is a valid way to demonstrate the design when equipment is unavailable.

Keep your plan, test notes and before-and-after evidence with the printable design brief below. Use the detailed teacher plan and any coding guide for tool instructions. These steps continue across the lesson’s meetings, not all in one sitting.

For teachers

Engineering standards

This shows how the lesson connects to the national NGSS engineering standards and what student work you can collect.

Assessed

3-5-ETS1-1

Teams define the user or purpose, success criteria, and limits before building.

What students show: Problem statement with measurable criteria and material constraints.
Practiced

3-5-ETS1-2

Students sketch and compare at least two solutions before choosing or combining features.

What students show: Two labeled ideas and an evidence-based design choice.
Assessed

3-5-ETS1-3

Teams use a repeatable low-tech test—pour the same measured water volume through each design and compare time plus visual clarity—then revise one feature.

What students show: Test notes, before-and-after design, and explanation of improvement.

Materials

  • Cut plastic bottles prepared by an adult or paper funnels
  • Gravel, sand, cotton, mesh, and coffee filters
  • Cups, trays, spoons, and prepared muddy test water
  • Rulers, pencils, markers, and planning paper
  • Masking tape, glue dots, paper fasteners, clips, and rubber bands
  • Scissors and other teacher-approved hand tools
  • Reused and student-proposed materials approved before use

Teacher preparation

  1. Set out a broad materials buffet instead of identical kits.
  2. Build one small test rig, not a finished example students may copy.
  3. Mark size, time, and material limits visibly.
  4. Prepare a team planning page and shared test-data table.
  5. Create a safe holding area for drying or unfinished builds.

Step by step

How to teach it

Day 1 · 0–20

Explore the challenge

  1. Introduce the mission: Build a model filter that improves the visible clarity of muddy test water while allowing it to flow through.
  2. Identify the user or audience and what success should look like.
  3. Explore how sample materials bend, fold, join, compress, slide, or balance.
Day 1 · 20–60

Imagine and prototype

  1. Each student sketches a different possibility.
  2. Teams compare ideas against criteria and constraints.
  3. Build a quick model using only part of the material budget.
Day 2 · 0–35

Build and test

  1. Complete the first working version.
  2. Use the same procedure each time: pour the same measured water volume through each design and compare time plus visual clarity.
  3. Record what worked, what failed, and where it happened.
Day 2 · 35–60

Improve with evidence

  1. Change one important feature rather than rebuilding randomly.
  2. Repeat the same test and compare results.
  3. Add color, surface, form, or story details that strengthen the purpose.
Optional Day 3

Gallery and challenge round

  1. Display designs with a one-sentence mission and test result.
  2. Let visitors try the project using the same rules.
  3. Teams explain one tradeoff and one idea they would try next.

Assessment

  • Problem statement includes a purpose, criteria, and constraints.
  • Sketches show meaningfully different ideas.
  • Material choices are explained using properties.
  • Test is repeatable and produces recorded evidence.
  • Revision responds to a specific result or failure point.

Supports & extensions

  • Offer picture directions and sample joining techniques.
  • Provide pre-cut pieces, adaptive scissors, or larger materials.
  • Allow students to explain through drawing, speaking, or demonstration.
  • Assign flexible roles: designer, builder, tester, recorder, and artist.
  • Extension: reduce material use while maintaining performance.

Safety & responsible use

  • Use only clean, teacher-approved reused materials.
  • Carry scissors and tools safely; cut away from hands and bodies.
  • Cover sharp cardboard corners, wire ends, skewers, or fasteners.
  • Use a defined test zone and keep faces away from moving or falling parts.
  • Teacher handles hot glue, craft knives, and any tool not approved for students.

No-machine alternative

The entire project is already designed for common classroom materials. Substitute paper folds, tabs, slots, string, tape, or found objects while keeping the same criteria and fair-test cycle.

Printable student design brief

The challenge

Build a model filter that improves the visible clarity of muddy test water while allowing it to flow through.

Success criteria

  • Water flows through the system
  • Output is visibly clearer than input
  • Layer diagram accurately explains the design

Constraints

  • Filtered water is never for drinking
  • Same water volume and test mixture for all teams
  • Wet work stays inside trays

Engineer’s notes

Our design should…
We chose this material because…
Our first test showed…
The failure point was…
We changed… because…
Next time we would…
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