← Back to Adventure

🧪 Filtering Water

Learn how dirty water gets clean!

0 of 4 sections explored
🏞️
Section 1
Why We Filter Water
👆 Tap to explore!

Water from rivers and lakes might look clean, but it can hide things you cannot see! Let's learn why we clean our water before drinking it.

🔬 Hidden Dangers! Water that looks clear can still have tiny germs too small to see. One drop of lake water can have thousands of them!
🌊 What's in Untreated Water? River water can have dirt, sand, leaves, and animal waste in it. All of that must be taken out before you can drink it.
🏭 Water Treatment Plants Are Amazing! Water cleaning plants clean over 34 billion gallons of water every day! That could fill 50,000 swimming pools. They work all day and all night so you always have clean water.
🕰️ Long Ago... Long ago, people got sick from dirty water. Ancient Egyptians were some of the first to filter water. They used sand and gravel over 4,000 years ago!
🤔 Scout Discussion

Have you ever seen a river that looked clean? Would it be safe to drink from? Why or why not?

🏗️
Section 2
How a Water Treatment Plant Works
👆 Tap to explore!

Water goes through many steps before it gets to your sink. Follow the path from dirty water to clean water!

Water Treatment Process 1. Screening Remove big stuff (sticks, leaves) 2. Coagulation Chemicals make dirt clump together 3. Sedimentation Clumps sink to the bottom 4. Filtration Sand & gravel catch tiny bits UV 5. Disinfection Chlorine or UV kills germs 6. Storage Clean water stored & sent to homes! Water gets cleaner at each step! Dirty 🟤 Clean 🔵
⏱️ How Long Does It Take? Cleaning water takes about 1 to 3 hours. Then the clean water flows through pipes under the ground to your house!
🧪 Coagulation Is Cool! Special stuff is added to the water that works like a magnet for dirt. Tiny dirt bits stick together and make big clumps. The clumps are heavy, so they sink to the bottom!
🤔 Scout Discussion

Which step do you think is the most important? Why? What if we skipped killing the germs?

🔧
Section 3
Build Your Own Water Filter!
👆 Tap to explore!

Now let's build your own water filter! This fun project shows how layers of sand and rocks can clean dirty water.

🚨 Safety Warning! The water from your filter is NOT safe to drink! It may look cleaner, but it can still have germs you cannot see. This is just to learn how filters work. Only drink water from a tap or a sealed bottle!

📦 Materials You Need

🍶 Big plastic bottle
✂️ Scissors (ask a grown-up!)
☁️ Cotton balls or coffee filter
🏖️ Fine sand
🏜️ Coarse sand
⬛ Charcoal (from a pet store)
🪨 Small rocks and pebbles
🪨 Large rocks
🥤 Cup or jar to catch water
🌿 Dirty water (mix water with dirt and leaves)

📋 Steps

  1. Ask a grown-up to cut the bottle in half. You will use the top half as your filter.
  2. Take the cap off. Flip the top half upside down like a funnel. Set it on top of your cup.
  3. Stuff cotton balls into the neck of the bottle. This is your finest layer.
  4. Add fine sand on top of the cotton (about 2 inches).
  5. Add chunky sand on top of the fine sand (about 2 inches).
  6. Add small rocks and pebbles (about 2 inches).
  7. Add big rocks on top (about 2 inches).
  8. Slowly pour dirty water in the top. Watch it drip through!
  9. Look at the water that comes out. Is it cleaner than before?
DIY Water Filter Pour dirty water in the top Large Rocks (catches big stuff) Small Gravel (catches medium bits) Coarse Sand (catches small bits) Charcoal (absorbs chemicals) Fine Sand (catches tiny bits) Cotton Balls (finest filter) Cleaner water! ✨ Cut Plastic Bottle (inverted)
🔬 What Happened? Water flows down through each layer. Big rocks stop big pieces. Gravel catches medium bits. Sand traps small stuff. Charcoal soaks up bad smells and tastes. Cotton catches the tiniest bits. Real water plants work the same way!
🧑‍🔬 Try This Experiment!
  • Pour the water through a second time. Does it get even cleaner?
  • Try dirty water with food coloring or soil. What does the filter catch best?
  • Change the order of the layers. Does it still work?
🚨 Remember! Even if the water looks cleaner, it is still NOT safe to drink. Your filter catches dirt, but it cannot catch tiny germs. Real water plants use special stuff to kill germs after filtering.
🤔 Scout Discussion

Why are the big rocks on top and the cotton on the bottom? What would happen if you put cotton on top instead?

🥾
Section 4
Backpacking Water Filters
👆 Tap to explore!

Hikers cannot bring a water cleaning plant with them! So how do they get clean water? Let's find out!

💪 Pump Filters

You pump a handle to push water through a filter. It is like a tiny water cleaning plant in your backpack!

🤏 Squeeze Filters

Fill a soft bag with water and squeeze it through a filter. Clean water comes out the other side!

💡 UV Pens

Stir this special light pen in your water for 90 seconds. The light kills germs. It is like a mini sun in your bottle!

🔥 Boiling

The oldest trick! Boil water for one minute and the heat kills germs. You just need a pot and a fire!

🔬 Incredibly Tiny Filters! Hiking filters have holes so tiny you cannot see them. The holes are 500 times thinner than a hair! Germs are too big to fit through.
🦠 What Can Get Through? Filters catch most germs, but some are even tinier. To kill those, you need UV light or boiling. That is why many hikers use more than one way to clean water!
⛰️ Fun Hiker Facts! A hiker walking the whole Appalachian Trail (over 2,000 miles!) might filter over 500 gallons of water. That is a LOT of clean water from one little filter!
🤔 Scout Discussion

If you went camping, which way would you clean your water? Why? Would you bring a backup way too?

🎊 You Did It!

You learned all about filtering water! You know how water plants work, how to build a filter, and how hikers clean water. Great job, Scout!