Hydro Logic Teacher Guide Hydro Logic
Teacher Facilitation Guide
Grade 6-8 Science
45-50 Minutes
Small Groups (3-4)
Hands-on Lab
Learning Objectives
Design and test a multi-stage filtration system to remove solid pollutants.
Differentiate between mechanical separation and chemical/biological treatment.
Analyze the limitations of physical filtration regarding pathogens and dissolved chemicals.
The "Dirty Water" Mix
Prepare 1 gallon for the whole class:
Tap Water 1 gallon
Potting Soil 1/2 cup
Dry Leaves/Twigs 1 handful
Vegetable Oil 2 tbsp
Food Coloring (optional) 3 drops
Lesson Timeline
1
Warm-up (5 Minutes)
Play the video segment (03:40-03:53 ).
2
Engineering Challenge (30 Minutes)
Groups design and build their filters using the Clear Water Challenge Worksheet .Crucial Rule: They must justify the order of their materials (e.g., "Big rocks first to catch the big stuff").
Observation Tip: Encourage students to look at the "after" water and the vegetable oil. Most filters will struggle with the oil, creating a bridge to the "Chemical Treatment" discussion.
3
Reflection & Comparison (10 Minutes)
Compare student results to the video (03:53-04:10 ). Discuss Good Microbes and UV/Chlorine .
Critical Discussion Prompts
The "What's Left?" Question
"Your water looks clear, but would you drink it? Why or why not?" Look for: Bacteria, invisible chemicals, nitrates from the intro.
The "Sustainability" Link
"How does this help us use a limited resource sustainably?" (Reference video 04:19). Look for: Recycling water, environmental protection.
Teacher Prep Checklist
Station Setup
Cut 2-liter bottles in half for each group (cap side = filter, bottom side = collection).
Divide gravel, sand, and cotton into bowls for easy access.
Set up a "Testing Sink" or large buckets for water disposal.
Common Misconceptions
"Clear = Clean"
"Filters remove everything"
Filter Frenzy Slides Environmental Science
FILTER FRENZY
Engineering solutions for a thirsty planet.
The First Line of Defense
Watch carefully! The first two steps of wastewater treatment focus on mechanical separation .
Look For:
How solids are removed.
What "mechanical" filtering means.
Embedded media
Recommended: Watch 03:40 - 04:10
THE DIRTY TRUTH
"Less than 1% of Earth's water is accessible fresh water, so we must protect it from pollution."
🪨
Solids
Dirt, leaves, sticks, and plastics.
🛢️
Chemicals
Oils, soaps, and fertilizers.
🦠
Pathogens
Bacteria and viruses (Invisible!).
Engineering Challenge
Your mission: Build a multi-stage filter to produce the clearest water possible from the provided "dirty" sample.
Constraints:
At least 3 distinct material layers.
Total build time: 20 minutes.
Must sketch design before building.
🪨 Gravel
🏖️ Sand
☁️ Cotton
☕ Filters
Analysis: Is It Safe?
Observation
Even if the water looks 100% clear, is it safe to drink? Why or why not? Think back to the video's mention of UV light and Chlorine .
The Invisible Threat
Bacteria & Viruses
Dissolved Chemicals (Nitrates)
Microplastics
"Salt water doesn't go through wastewater treatment like drinking water does."
Pollutants like mercury bioaccumulate in tissues and biomagnify up the food chain. Mechanical filters can't stop this!
Become a Solution
Reduce Plastic
Stop microplastics at the source.
Dispose Properly
Never flush meds or chemicals.
Educate
Share what you've learned today!
Clear Water Challenge Worksheet CLEAR WATER CHALLENGE
Engineering Design & Filtration Lab
Engineer Name
Date / Group ID
1
Stage 1: Design Phase
Sketch your multi-stage filter below. Label each layer (Gravel, Sand, Cotton, Filter Paper) and explain why you chose that order.
Available Materials:
• Large Gravel
• Fine Sand
• Cotton Balls
• Coffee Filters / Cloth
• 2L Bottle (Housing)
Blueprinting Area (Sketch Layers Here)
2
Stage 2: Observation & Data
Metric Before Filtration After Filtration Clarity (1-10) Pollutants Seen Presence of Oil
3
Stage 3: Engineering Analysis
Which layer was most effective at removing "solid pollution"? Why?
What did your filter NOT remove? (Think about chemicals, oil, or invisible particles).
BEYOND THE FILTER
Wastewater treatment plants use Microbes (biological) and UV Light/Chlorine (chemical) after the mechanical screens. Why are these steps necessary for human health?
Group Build Instructions Handout BUILD GUIDE
Team Engineering Instructions
Time Allotted
30:00
Assign Team Roles
Lead Engineer
Oversees the assembly and ensures the design plan is followed.
Materials Manager
Collects and manages gravel, sand, and cotton layers.
Data Recorder
Documents observations and completes the Clarity Table.
Assembly Steps
1
Prepare Housing
Invert the top half of your bottle (the cap side) and place it into the bottom half. Secure with tape if needed.
2
Base Layer
Place cotton balls or a coffee filter in the neck of the bottle. This stops your filter materials from falling into the clean water!
3
Layering
Add your chosen materials (sand, gravel, etc.) in the order your team designed. Tamp down each layer lightly.
4
The Pour
Slowly pour 200ml of "Dirty Water" onto the top layer. Do not pour too fast or you will flood the filter!
Typical Setup
DIRTY WATER
GRAVEL
SAND
COTTON
Note: Your team's order might be different! This is just an example.
Engineer Pro-Tip:
Think about particle size. Should the biggest rocks go at the top to catch large leaves, or at the bottom to support the smaller sand particles? Discuss with your team!
