Let's Make a Change
$34.99
Introduction
Behold Waitī, the whetū (star) that looks after our freshwater systems and the creatures that thrive within it. Waitī, a star in the Matariki cluster, allows us an abundance of clean water in Aotearoa. So how can we make water clean enough to drink?
Nature has its own way of cleaning water, using layers like sand, soil, and stone. Before it reaches our taps, water goes through natural and human-made filters—removing dirt, rocks, and even germs.
In this experiment, you’ll build your own mini water filter using natural materials like cotton, sand, charcoal, and rocks. Then you’ll pour dirty water through it and watch how it becomes cleaner—just like in the natural world! But remember, this is just an example - the water still isn't safe to drink.
As we learn about filtering water, we remember how precious fresh water is and how important it is to care for it under the domain of Waitī.
Step 1:
Gather all your materials:
• Takawai kirihou - Large plastic water bottle
• Pōro kātene - Cotton balls
• Onepū - Sand
• Ngārahu - Charcoal (crushed)
• Toka - Rocks of different sizes (gravel, pebbles and small rocks)
• One - Dirt or soil
• Kōata - Glass
• Kutikuti - Scissors
• Ipu ine - Measuring cup (optional)
Step 2:
With the help of an adult, cut the bottom off the plastic bottle (about 1/3 of it). Keep both parts—you’ll use the bottom part to hold your dirty water.
Step 3:
Place the cotton into the neck of the bottle and then a layer on top of that as flat as you can.
Tip: You can balance the bottle upside down in your glass while you build your filter.
Step 4:
Pour sand into the bottle on top of the cotton. Spread it out evenly.
Step 5:
Next, add a layer of crushed charcoal on top of the sand. Spread it out evenly, just like you did with the sand.
Step 6:
Add your rocks, starting from smallest to largest. For example, put your gravel in first, then the larger rocks.
You now have a filter that represents the natural world.
Step 7:
In the bottom part of the bottle (that you cut off earlier), mix about ½ cup of water with a small handful of dirt to make 'dirty water'.
Step 8:
Place your filter (the top of the bottle, now filled with layers) upside down on your glass. Carefully pour the dirty water through it.
Watch what happens as the water moves through each layer!
Remember you still cannot drink this water.
Reflect
- Which layers seemed to be the most important or effective in filtering the water? Why?
- Why do you think the order of the layers matters in a water filter? What might happen if you mixed the layers up?
- How could you test the cleanliness of your filtered water?
How It Works
This experiment shows how water can be cleaned by passing through different layers of natural materials, just like it does in nature. As the dirty water moves through rocks, charcoal, sand, and cotton, larger particles (like dirt and debris) get trapped, leaving the water looking clearer. Each layer filters out different sizes of particles—charcoal also helps reduce smells and some impurities. This process is attributed to Waitī, the star linked to freshwater and the systems that keep it flowing clean and healthy.
