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Water filtration systems

Girl and boy examining coloured glasses of water

Project information

Not everyone’s cup of tea!

While most children playing in the mud kitchen just pretended to drink their ‘cups of tea’, one child did drink the dirty water, which started a discussion on why we should not do that. When one of the educators showed the children a video about parts of the world without access to clean drinking water, the children decided to invent a water filtration system.

Finding solutions to a problem

Starting with creating a jar of dirty water by adding mud, bark, sand and pebbles to it, the children discussed what they would do if they only had dirty water to drink. They thought that they could “scoop the bits out” or “wash the water in the rain” and what instruments could they use to clean the water? “A scoop” or “the bowl with holes in,” they suggested.

The children noticed that the bark floated, while pebbles and sand sunk to the bottom of the jar. They managed to get some of the bark out using a slotted spoon but the water was still dirty. They also left a tray of dirty water out in the rain over night. In the morning, they noticed that the tray had more water in it, but it was still dirty.

Testing prototypes

The children became engineers and used sieves, cups, sponges, rubber bands, tape, dish cloths, fabric and other resources to build their own filtration systems. We then tested the systems to see if the water came out cleaner and assessed which designs worked well and which were least successful.

No fishing in murky waters

Throughout the project, the children used a planning sheet, in which they recorded why the water was dirty, how they proposed to clean it and what resources they would need. Younger children worked with older children, who could help with drawing. The sheet also included a space for them to reflect – “Did it work?”

Optimising designs

The children tested and optimised their designs and conducted technical experiments to find out which materials worked as filters. They demonstrated each filter system to the group, which enabled them to learn from each other as they took inspiration to adapt their own systems.

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