Water Filters – Bay Area Discovery Museum

Water Filters

Can you make dirty water clean? Design, create, and test your own water filter to find out!

Materials Required

  • Pebbles and/or gravel
  • Sand
  • Coffee filters
  • Cotton balls
  • Small scoopers
  • 3 pre-made tester filters
  • 1 bucket of dirty water
  • Empty bucket
  • Empty plastic bottles cut in half, hole drilled into lid
  • Pencil and paper
  • 4 bins or baskets

Instructions

  1. Set up each material neatly in a separate bin or basket.
  2. Demonstrate that the pre-made filters can be used to make dirty water cleaner.
  3. Remind children it is not safe to drink the water at any point in the activity.
  4. Challenge the children to make their own water filter using the materials available. Show them the sorted items and ask them to plan their own design using pencil and paper.
  5. Invite each child or team of children to get one empty half bottle and fill it using the materials (pebbles, sand, coffee filters and cotton balls) in any quantity, combination, and order that they choose.
  6. Once children have filled their bottles, they can test their filters by pouring dirty water through it.
  7. Ask children to make observations and changes to their filters: What happened when you poured the dirty water through it? Did the water change in any way? What could you do to make your filter better?

Additional Tips

Try these add-on activities:

  • Ask children to record their observations about each iteration of their design. Which design worked best? Why do they think that happened?
  • Try sending the same water through the filter multiple times. What happens?
  • For older children, explore and discuss: Why is the water dirty? Why can’t we drink it? Perform a test using a purchased water quality test kit to see if the filtered water is actually clean and potable. Emphasize how the type or size of the filter is related to the type of contaminant in the water.

Links to Creativity

As educators and researchers continue to explore and develop best practices for teaching STEM to children, their findings often point to how children’s exploration and parent’s explanations are not mutually exclusive (Callanan & Oakes, 1992). Encouraging children to playfully explore materials and concepts often leads to explanations of what was found, and these explanations lead to further exploration as children seek even more information. This process unfolds as children attempt many iterations of filter systems for this activity. Along the way, they discover the many variables involved (e.g., the materials chosen, the amount of those materials, etc.) and begin testing how each interacts with the next. This Control for Variables (see Chen & Klahr, 1999) is not only akin to hypothesis testing, but helps identify individual features of materials that can lead to some very creative solutions to a problem as big as water filtration (McCaffrey, 2012).

Supporting research includes:

Callanan, M. A., & Oakes, L. M. (1992). Preschoolers' questions and parents' explanations: Causal thinking in everyday activity. Cognitive Development, 7(2), 213-233.

Chen, Z., & Klahr, D. (1999). All other things being equal: Acquisition and transfer of the control of variables strategy. Child Development, 70(5), 1098-1120.

McCaffrey, T. (2012). Innovation relies on the obscure: A key to overcoming the classic problem of functional fixedness. Psychological Science, 23(3), 215-218.

Contributor

This activity was contributed by the Bay Area Discovery Museum. ©2017 Bay Area Discovery Museum. For more information and resources see BayAreaDiscoveryMuseum.org

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SCOPE OF ACTIVITY

CREATIVITY SKILLS USED

Water Filters

Can you make dirty water clean? Design, create, and test your own water filter to find out!

  • Pebbles and/or gravel
  • Sand
  • Coffee filters
  • Cotton balls
  • Small scoopers
  • 3 pre-made tester filters
  • 1 bucket of dirty water
  • Empty bucket
  • Empty plastic bottles cut in half, hole drilled into lid
  • Pencil and paper
  • 4 bins or baskets
  1. Set up each material neatly in a separate bin or basket.
  2. Demonstrate that the pre-made filters can be used to make dirty water cleaner.
  3. Remind children it is not safe to drink the water at any point in the activity.
  4. Challenge the children to make their own water filter using the materials available. Show them the sorted items and ask them to plan their own design using pencil and paper.
  5. Invite each child or team of children to get one empty half bottle and fill it using the materials (pebbles, sand, coffee filters and cotton balls) in any quantity, combination, and order that they choose.
  6. Once children have filled their bottles, they can test their filters by pouring dirty water through it.
  7. Ask children to make observations and changes to their filters: What happened when you poured the dirty water through it? Did the water change in any way? What could you do to make your filter better?

Try these add-on activities:

  • Ask children to record their observations about each iteration of their design. Which design worked best? Why do they think that happened?
  • Try sending the same water through the filter multiple times. What happens?
  • For older children, explore and discuss: Why is the water dirty? Why can’t we drink it? Perform a test using a purchased water quality test kit to see if the filtered water is actually clean and potable. Emphasize how the type or size of the filter is related to the type of contaminant in the water.
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