Science Lesson Kit · Teacher Resource
Water Filtration Challenge: Design, Test & Improve a Filter — 5E Lesson Plan
Earth Science · 55 minutes
Grade 5
5E lesson flow
01
Engage
6 min
Teacher Does
Show a cloudy sample and two possible filter media without suggesting the water becomes drinkable.
Students Do
List what might be removed and what cannot be seen.
Ask
- Will visibly cleaner mean safe to drink?
Look For
Students state a visibility limit and water safety caution.
02
Define
8 min
Teacher Does
Set criteria: visibility improvement and minimum collected volume; state material/time constraints.
Students Do
Rank desired outcomes and sketch a prototype.
Ask
- What does success mean before we test?
Look For
Clear measurable criteria and recognized design constraints.
03
Build
10 min
Teacher Does
Provide classroom-prepared safe media and coach consistent sample setup.
Students Do
Assemble two different supported filter designs.
Ask
- Which one feature is different between your designs?
Look For
Fairly comparable prototypes and safe setup.
04
Test
13 min
Teacher Does
Time both tests and model recording volume and clarity against the same background.
Students Do
Pour equal model-water amounts and log both outcomes.
Ask
- Does the clearer filter also collect more water?
Look For
Measurements for both criteria, not judgment from a single feature.
05
Redesign
10 min
Teacher Does
Challenge teams to explain one change from data; retest if classroom time allows.
Students Do
Propose a specific redesign and expected effect.
Ask
- Which observation tells you what to change?
Look For
An evidence-linked improvement and identified trade-off.
06
Evaluate
8 min
Teacher Does
Present independent River Rescue print case and the non-drinking reminder.
Students Do
Reason with new results and write a bounded claim.
Ask
- Why can nobody drink even the clearest sample?
Look For
Data-based evaluation and safety limitation.
Student goal
I can compare two classroom filter prototypes fairly and redesign one using both visible clarity and measured water recovery.
Learning objectives
- Describe what classroom filters can and cannot remove from modeled dirty water.
- Use criteria, constraints, and a fair test to compare two filter designs using visible particles and recovered water volume.
- Explain a specific redesign using data while clearly stating that the filtered water is never safe to drink.
Materials
- Two identical prepared filter holders per group (teacher-cut bottle tops or funnels)
- Coffee filters
- Clean gravel and clean sand (optional)
- Cloth or cotton pads
- Identical measuring cups
- Teacher-prepared water mixed with a little clean sand/soil
- Collection cups
- Clarity reference card
- Timer
- Trays and towels
- Safety goggles
Before class
- Make all bottle cuts in advance; smooth or cover sharp edges.
- Prepare model water using small amounts of clean classroom sediment only; do not use real wastewater.
- Pretest a feasible 100 mL sample and ensure filters will drain within the lesson time.
- Set a common test window and simple clarity scale (1=very cloudy, 5=least cloudy).
- Label every station 'DO NOT DRINK'.
- Plan cleanup and sediment disposal without washing excessive sand down drains.
Safety & supervision
Review these precautions before students begin the investigation. Follow your school's safety procedures.
- Do not drink, taste or splash the model water before or after filtering.
- Teacher cuts any bottles before the activity; cover sharp edges.
- Use clean approved sediment only, not real contaminated water.
- Avoid airborne dust and wash hands afterward.
Prior knowledge
- Some materials can be trapped by a filter while water passes through.
- Engineers choose criteria and constraints before testing.
Vocabulary
- filtration
- A method that traps some materials while a fluid passes through.
- filter medium
- A material, such as a coffee filter or gravel layer, used in a filter.
- sediment
- Small particles of Earth material such as sand or soil.
- turbidity
- How cloudy water looks because of particles suspended in it.
- criteria
- The conditions a design should meet to solve a problem.
- constraint
- A limit on a design, such as time, materials or size.
- prototype
- An early model built to try out and improve an idea.
- redesign
- A change to an existing prototype based on evidence from a test.
Differentiation
- Offer a labeled funnel diagram with movable filter-layer picture cards.
- Use a comparison table with preprinted clarity and volume columns.
- Provide the sentence starter: 'I would change ___ because our data showed ___.'
- For extension, add flow rate (mL/min) and discuss clarity–volume trade-offs.
Assessment
- Score prototype comparison on BOTH criteria.
- Check constant initial water volume and test duration.
- Review independent worksheet reasoning, not just which filter looks clear.
- Check every student articulates the no-drinking limitation.
Exit ticket
Our clearest filter gives only half as much collected water. Name one possible design trade-off and one safety limitation.
Extension
Graph clarity scores against collected volume for several prototypes; identify which designs satisfy the preset criteria.