Fifth Grade · Science · week 8

Design: filtration system

Design, describe, and test a multi-step filtration system that separates a mixture, then evaluate and improve it.

Engineers do not just study matter, they use what they know about matter to solve real problems. Clean drinking water is one of the biggest engineering challenges in the world, and it usually starts with filtration: passing dirty water through layers of material that trap different sized particles while letting clean water through.

A good filter design usually layers materials from coarse, with big gaps, like gravel, to fine, with tiny gaps, like sand or cloth, so big particles get caught first and small particles get caught last. This week you design your own layered filter, predict how it will perform, test it, and then improve it; that improve-and-retest step is real engineering.

📋 For the teacher
Teach it (10–15 min):
  • If you can, actually build a simple layered bottle filter and test it with muddied water outside or over a sink; real results teach more than an imagined test.
  • Push the test, evaluate, improve cycle explicitly: what worked, what did not, what is the next change?
  • Be honest that home filtration does not make water certified safe to drink; this is about the engineering process, not a real water-safety solution.
  • Let a first attempt that does not work well be a genuine part of the lesson; the redesign is the most valuable step.
Talk about it:
  • Why does layer order matter in a filtration design?
  • What would you change if your filter did not work as well as you hoped?
  • Why do engineers test and redesign instead of just building once?

Mastery looks like: They can describe a layered filtration design, predict its performance, and propose a specific improvement based on a test result.

Common stumbles: Assuming any filter automatically makes water perfectly clean or safe; giving up after one attempt instead of redesigning.

Homework for this lessonType it, write it with a stylus, or print it for pencil & paper.open →
Records attendance + 15 min of Science for this learner.
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