A collaborative 7th-grade science research project investigating atmospheric water harvesting, phase changes, and clean water solutions through group research and presentations.
Water Harvest STEM Presentation Project • Grade 7 Science Page 3 of 3 • End of Project Guide
Topic 1: Dew Harvesting • Student Research Dossier Page 1 of 5
Topic 2 Research Sheet • Middle School Science
Fog Catchers: Giant Nets in the Clouds
POWERED BY WIND
Quick Summary (What is this?)
Fog harvesting uses nets or mesh screens to catch tiny liquid water droplets carried by fog. The droplets join together, run down the screen, and collect in a container.
The Problem: Mountain Towns with No Rain
High up in coastal mountains (like in Chile and Morocco), rain almost never falls. But every single morning, thick, cold ocean fog clouds roll across the mountains. Residents and families used to walk hours just to find water until engineers put up giant nets!
How It Works (In 3 Easy Steps)
1 Wind Blows Fog
Strong winds push low-hanging fog clouds directly into giant plastic mesh nets stretched out between metal poles.
2 Droplets Collide
Microscopic water drops in the fog crash into the mesh threads. They stick and bump into each other, joining together into big, heavy water drops.
3 Gutter Drain
Gravity pulls the heavy water drops down into a bottom gutter pipe. The clean water flows through pipes right into village homes!
Vocabulary Helper (Easy Words)
Fog: A cloud that is touching the ground, made of millions of tiny floating water drops.
Coalesce (Combine): When tiny little droplets bump into each other and merge into one big drop.
Mesh: An open net made of crisscrossing plastic threads.
By the Numbers (What to Expect)
Water Made: 1 to 5 big buckets (up to 20 liters) per net every day!
Power Needed: Zero! Powered by the wind.
Poster Cheat Sheet (Put these answers on your poster!)
Quick Presentation Facts
Where does it work best? On windy mountain ridges near the ocean that get thick morning fog.
The Best Thing (Pro): Produces thousands of gallons for whole towns without electricity!
The Biggest Problem (Con): If the wind stops or the fog disappears, no water is made.
Topic 2: Fog Harvesting • Student Research Dossier Page 2 of 5
Topic 3 Research Sheet • Middle School Science
The Desert Sponge: Water from Super-Dry Air
SOLAR HEATED
Quick Summary (What is this?)
Atmospheric water harvesting uses special sponge-like powders to pull water straight out of bone-dry desert air. When the morning sun warms up the box, the trapped water is released as pure liquid drinking water.
The Problem: When Air is Too Dry for Normal Traps
Ordinary dew and fog collectors only work when the air is humid. But in super-hot deserts like the Sahara or Death Valley, the air is bone-dry. Scientists had to invent a high-tech "molecular sponge" that can suck water out of air that feels completely dry!
How It Works (In 3 Easy Steps)
1 Soaking Up at Night
At night, the box opens. A special powder with trillions of microscopic holes acts like a super-sponge, grabbing hidden water gas out of the dry air.
2 Sunlight Warms It
When morning arrives, the clear lid closes. Warm sunshine heats up the powder inside, forcing the trapped water to escape as warm steam.
3 Dripping Water
The warm steam hits a cooler metal plate, condenses back into liquid water drops, and drips into a clean drinking cup!
Vocabulary Helper (Easy Words)
AWH: Short for Atmospheric Water Harvester (a machine that catches water from air).
Sponge / Sorbent: A special chemical material made to soak up water gas.
Evaporation: When heat turns liquid water into gas or steam.
By the Numbers (What to Expect)
Water Made: 2 to 5 bottles of water every day from a small box.
Power Needed: Natural sunshine or a small solar panel.
Poster Cheat Sheet (Put these answers on your poster!)
Quick Presentation Facts
Where does it work best? In super-dry inland deserts where other water systems fail.
The Best Thing (Pro): Works in the driest air on Earth using only sunlight!
The Biggest Problem (Con): The special powder is new technology and still expensive to make.
Topic 3: AWH Devices • Student Research Dossier Page 3 of 5
Topic 4 Research Sheet • Middle School Science
Desalination: Turning Ocean Water into Tap Water
BIG CITY SCALE
Quick Summary (What is this?)
Desalination turns salty ocean water into safe, fresh drinking water. Powerful pumps push ocean water through microscopic plastic filters under extreme pressure. The filter blocks all the salt, while clean water passes through!
The Problem: Water, Water Everywhere, But Not a Drop to Drink
Over 97% of all water on Earth is salty ocean water. Humans cannot drink salt water because the salt makes our bodies dangerously dehydrated. Desalination takes the salt out so millions of people can drink!
How It Works (In 3 Easy Steps)
1 Suck & Clean
Giant pipes pull seawater from the ocean. Sand filters remove seaweed, sand, and tiny floating dirt pieces so the water is clear.
2 High-Pressure Push
Enormous electric pumps push the salty water with giant force (like being deep underwater) against a special filter called a membrane.
3 Salt Blocked!
The filter holes are so tiny that only pure water fits through! Salt, bacteria, and minerals are trapped and washed away as salty wastewater.
Vocabulary Helper (Easy Words)
Desalination: Removing salt from ocean water.
Reverse Osmosis: Squeezing water through a microscopic sheet to trap salt.
Brine: The super-salty leftover water that gets sent back to the sea.
By the Numbers (What to Expect)
Water Made: Millions of gallons every day for entire cities!
Power Needed: Very High! Needs big power plants.
Poster Cheat Sheet (Put these answers on your poster!)
Quick Presentation Facts
Where does it work best? In coastal cities near the ocean that have lots of electricity.
The Best Thing (Pro): The ocean never runs out of water, even during terrible droughts!
The Biggest Problem (Con): Uses huge amounts of electricity and costs lots of money.
Topic 4: Desalination • Student Research Dossier Page 4 of 5
Topic 5 Research Sheet • Middle School Science
Rain Catchers: Saving Every Storm Drop
CHEAP & EASY
Quick Summary (What is this?)
Rainwater harvesting catches and stores natural rainwater right where it falls from the sky. Gutters catch the storm water on roofs and send it through simple dirt filters into storage tanks before it can hit the dirty ground.
The Problem: Good Water Washes Down the Drain!
Rain is naturally pure, fresh water. But when it falls on streets, parking lots, and dirt, it picks up oil and garbage and rushes down street drains as polluted runoff. Catching it on roofs saves hundreds of gallons of clean water!
How It Works (In 3 Easy Steps)
1 Rooftop Slide
Rain falls on smooth metal or tile roofs. The slanted roof acts like a slide, channeling water into metal gutters along the edge.
2 Dirty Water Trap
The first 5 minutes of rain washes dust and bird droppings off the roof into a special pipe. A floating ball seals that pipe shut!
3 Clean Storage Tank
Now only crystal clean storm water flows into a big covered tank (called a cistern) to be used for gardens, toilets, and drinking.
Vocabulary Helper (Easy Words)
Catchment: The surface (like a roof) that catches rain.
Cistern: A large, clean storage tank kept in the dark so green algae cannot grow.
First-Flush Diverter: A clever pipe that throws away the first dirty rain.
By the Numbers (What to Expect)
Water Made: Over 600 gallons from just 1 inch of rain on a house!
Power Needed: Zero! Gravity does all the work.
Poster Cheat Sheet (Put these answers on your poster!)
Quick Presentation Facts
Where does it work best? Any house, school, or farm that gets seasonal rainstorms.
The Best Thing (Pro): Super cheap, simple to build, and catches hundreds of gallons!
The Biggest Problem (Con): If it doesn't rain for months, your tank runs completely dry.
