Clean Water Designs

Overview

Students investigate how light-based energy ideas connect to Earth systems by focusing on a real-world Earth challenge: removing muddy contaminants from water. In an engineering design cycle, students build and test simple filtration systems, then refine their designs based on evidence, meeting Grade 5 Earth science expectations through hands-on experimentation.

Learning intentions

Students will be able to:

• describe how light and energy can help us observe materials and changes during an investigation
• engineer a filtration system using everyday materials to improve the quality of water
• test their system using clear measurements/observations and explain how design changes affect results
• explain patterns in how different filter materials (and layers) perform and why

Success criteria

• I can build a filtration system that reduces visible particles compared to my control sample.
• I can record what I changed (materials/layers) and what happened (results) using tables and observations.
• I can explain my best design using evidence from my tests.
• I can describe how my observations (including light/clarity) show the system is working.

Curriculum links

• TEKS.SCI.5.8.A: investigate and describe transformations of energy in systems (using observations with light to support investigation meaning)
• TEKS.SCI.5.8.C: demonstrate and explain how light travels and can be reflected, refracted, or absorbed (using flashlight/light to detect clarity changes in filtered vs. unfiltered water)
• TEKS.SCI.5.8.B: demonstrate how electrical energy in complete circuits can transform into light (classroom flashlight/circuit demonstration to support observation tools)
• TEKS.SCI.5.12.B: predict how changes in a system affect cycling/flow of matter and energy in environments (filtering as a model for how matter is separated/retained to affect flow)
• TEKS.SCI.5.12.C: describe a healthy ecosystem and how human activities can be beneficial or harmful (clean water filtration as a human action affecting ecosystem health)

Lesson structure (60 minutes)

1. 0–6 min · Hook (Observe “dirty water”). Teacher pours a sample of muddy water into a clear cup and shines a flashlight through it; students predict what they will see after filtration and why light looks different through cloudy water.

2. 6–12 min · Mini direct teach (Light + testing). Teacher reviews: light travels in straight lines and cloudiness changes how much light passes through (students describe what changes they expect to measure/notice using flashlight “beam clarity”). Students identify one observable indicator (brightness/clarity, particle settling).

3. 12–18 min · Engineering challenge prompt. Teacher explains the task: “Engineer a simple water filtration system that makes the water clearer using everyday materials.” Students choose materials and sketch a quick plan (layers, order, and a support method).

4. 18–35 min · Build & run Test 1 (control vs. filtered). Teacher provides materials and models safe handling; students build their first filter and pour the same volume of dirty water through it into a collection cup. Students record results in a table: time to filter, visible clarity (0–3 rating), and an image-free written description.

5. 35–44 min · Evidence check (Use light as a measurement tool). Teacher re-shines the flashlight through both unfiltered and filtered samples; students compare brightness/visibility of the “beam path” and complete a short observation note explaining what changed. Students discuss whether their design improved clarity and why.

6. 44–55 min · Redesign & run Test 2 (iterate). Teacher prompts: “Choose one change at a time” (e.g., add an extra layer, change order, tighten spacing, add a pre-filter layer). Students refine their filter, run Test 2, and update the data table with the same measures.

7. 55–60 min · Share & exit ticket. Teacher selects two quick share-outs; students explain their best design decision using evidence and complete an exit ticket: “What design change improved results, and what did you observe?”

Resources

• 2–3 cups of muddy water samples (same initial batch if possible)
• Clear plastic cups or containers for filtration and comparison
• Flashlights (one per group or shared station) and access to darkened area or consistent lighting
• Funnel-like structures: plastic bottles cut in half, cups with holes, or paper cones
• Everyday filter materials: coffee filters, paper towels, sand, small gravel/rocks, cotton balls, activated charcoal (optional), fabric scraps (as appropriate)
• Measuring tools: measuring cups or marked cups; timer
• Data sheet (table for Test 1 and Test 2): material layers, time, clarity rating, observations
• Safety supplies: paper towels, gloves if available, trash bin for used filter material
• Whiteboard or chart paper for class comparisons

Assessment

• Formative during build: teacher checks that students include a testable design plan (materials + order) before Test 1.
• Formative during testing: teacher reviews students’ data tables for consistency (same volume, same clarity scale).
• Exit ticket (quick): students must identify one design change and one evidence-based observation.

Differentiation

• Provide sentence starters: “I changed… because…,” “My evidence is…,” “A pattern I noticed is…”
• Offer a scaffolded materials “menu” with recommended layer options for students who need structure; allow more freedom for others.
• For students who finish early: challenge them to predict and justify which layer order will improve results before Test 2.
• ELL support: visual labels for materials (sand/gravel/paper/cotton), and allow oral responses recorded by the partner or teacher if needed.