Straining Out the Dirt

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Learners take on the role of environmental engineers as they design water filters. Learners see how polluted water (water with chocolate powder mix) can become clearer when passed through their filter of sand, marbles, granulated activated carbon, and cotton balls. Resource contains suggestions for assessment, extensions, and scaling for different levels of learners.

Quick Guide

Preparation Time:
10 to 30 minutes

Learning Time:
45 to 60 minutes

Estimated Materials Cost:
$5 - $10 per group of students

Age Range:
Ages 11 - 14

Resource Types:
Activity, Experiment/Lab Activity, Lesson/Lesson Plan, Model


Materials List (per group of students)

  • 0.5 liter (500 mL) plastic water or soda bottle
  • ½ cup granulated activated carbon (GAC) (available from chemical supply stores or pet supply stores in the aquarium section)
  • 2-3 cotton balls
  • Jar (smaller in diameter than the 500 mL bottle so that the water bottle can be supported in the jar without falling through)
  • Drill with small diameter bit (adult use)
  • Kitchen knife or scissors (adult use)
  • 3 tsp. of chocolate powder mix (such as Hershey's® or Nestle Quik®)
  • Water (enough water for each bottle to be filled up 3-4 oz.)
  • Pitcher or bucket for mixing powdered chocolate and water
  • 4-5 cups of sand
  • 50+ marbles


  • Earth and Space Science
    • Earth Structure
      • Oceans and Water
  • Engineering and Technology
    • Engineering
      • Environmental Engineering
  • Life Sciences
    • Ecology
      • Human Impact
  • The Nature of Technology
    • The Design Process
      • Research and Development
      • Invention and Innovation

Informal Categories

  • Model Building


To use this activity, learners need to:

  • see
  • see color
  • touch

Learning styles supported:

  • Involves hands-on or lab activities


Includes alignment to state and/or national standards:

This resource is part of:

Access Rights:

  • Free access


  • Schaefer, Malinda ; Pérez-Suárez, Sharon D. ; Lundberg, Matt ; Heavner, Ben ; Yowell, Janet

Source Collection

  • TeachEngineering


  • All rights reserved, Regents of the University of Colorado, 2004

Funding Sources:

  • National Science Foundation, 0226322
  • Fund for the Improvement of Postsecondary Education (FIPSE)
  • U.S. Department of Education