Low-Tech Water Filter for High-Impact Clean

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In this activity, learners consider the water features they might enjoy at a community park--a pond, brook, water playground (or "sprayground"), or pool--and what happens to the water over time. In small groups, they explore and test common materials to identify the best low-tech materials that can be used to help filter water. This activity is part of a curriculum designed to engage learners in hands-on engineering challenges.

Quick Guide

Preparation Time:
10 to 30 minutes

Learning Time:
10 to 30 minutes

Estimated Materials Cost:
Over $20 per group of students

Age Range:
Ages 4 - 14

Resource Types:
Activity, Demonstration, Lesson/Lesson Plan, Model


Materials List (per group of students)

  • computer, speakers, projector, projection screen, and access to the Internet (optional)
  • a writing surface where the groups may sketch and write (optional)
  • 5–6 (2-L) empty, clear plastic water bottles with the label and cap removed (preferably cleaned and repurposed for this activity)
  • 1 (16-oz. or larger) clear plastic container, such as a measuring cup
  • 10 rubber bands
  • 10 or more (~10" × 5") pieces of silk and/or cotton knit fabric, such as clean, discarded clothing or scraps from a fabric store
  • 6 cups of play sand
  • 5 cups of small aquarium gravel
  • 10 (~1") chunks of lava rock
  • 4 cups activated carbon/charcoal (sold at aquarium supply stores)
  • a selection of additional filtration materials to choose from, such as 1 cup of rice, 30 (5/8") marbles, 30 non-biodegradable Styrofoam "peanuts," 10 (1"x1") pieces of synthetic sponge, 1 package of cotton balls, 10 (5"x5") pieces of quilt batting, 2 cups shredded paper, 10 coffee filters
  • ~2 teaspoons of tea leaves (or the contents of 3–4 tea bags)
  • 3 cups boiling hot water
  • 1 (1-quart) tea pot or Pyrex measuring cup
  • 2 or more (~1-cup) containers for holding and pouring “dirty water,” such as measuring cups (preferably with spouts for easy pouring) or clean, empty personal water bottles
  • 2 or more labels or pieces of masking tape
  • 6 teaspoons or medicine droppers
  • 6 empty jars, pitchers, or other containers for collecting filtered water for later disposal
  • microscope, microscope slides, and water samples collected from a park fountain, stream, pond, or lake (optional)
  • 15–20 aprons or trash bags to wear over clothing
  • Safety signs, which read “Be safe! Do not drink this water”
  • 1 (8½" × 11") Be Creative…Be an Engineer! poster (for tweens, teens, and adults)
  • 1 (8½" × 11") Grand Challenges of Engineering poster (for teens and adults) (optional)
  • 1–2 (36" × 3 yards) packages of cheesecloth, purchased from a supermarket or kitchenware store


  • Earth and Space Science
    • Earth Structure
      • Oceans and Water
  • Engineering and Technology
    • Engineering
      • Bioengineering/Biomedical Engineering
      • Civil Engineering
      • Environmental Engineering
    • Technology
      • Agriculture and Biotechnology
  • Life Sciences
    • Ecology
      • Human Impact
  • The Nature of Science
    • The Scientific Process
      • About Inquiry
      • Asking Questions
      • Conducting Investigations
    • Science as a Career
  • The Nature of Technology
    • Technology and Society
      • Impacts of Technology
      • Technology and the Environment
    • The Design Process
      • Research and Development
      • Invention and Innovation
      • Problem Solving
      • Troubleshooting and Maintenance

Informal Categories

  • Nature and Environment


To use this activity, learners need to:

  • see
  • touch

Learning styles supported:

  • Involves teamwork and communication skills
  • Uses STEM to solve real-world problems
  • Involves hands-on or lab activities


Components that are part of this resource:

Includes alignment to state and/or national standards:

This resource is part of:

Access Rights:

  • Free access



  • , Lunar and Planetary Institute, 2013

Funding Source:

  • NSF, DRL-1010844