Grade 5 · Science · Lesson 36

Water filter STEM challenge

Around the world, billions of people use simple layered filters to clean cloudy water before drinking it. In this STEM challenge you will design, build, and test your own mini water filter using a plastic bottle and four materials: cloth (or a coffee filter), activated charcoal, sand, and gravel. Your goal is to turn a sample of dirty water into water that is clearly cleaner — and to do it as a fair test so you can compare your filter to a classmates.

What this lesson teaches

1Build a layered water filter that turns dirty water into clearer water
2Explain the role of each layer (cloth, charcoal, sand, gravel) in trapping particles
3Identify the variables that must stay the same to make the test fair
4Evaluate filter performance using clarity and filtration time as evidence

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