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How Can We Find Out What Is in Water?

Author(s): Nancy P. Moreno, PhD, Barbara Z. Tharp, MS, and Judith Dresden, MS.

Let’s Get Started

  1. Give each student group 1 or 2 basket-type coffee filters, from which they will prepare test strips. Have students smooth and flatten the filters. Then, each student should cut a filter strip about 2-cm wide and 10-cm long.

  2. Give each group a 250-mL beaker with about 1 cm of mystery liquid in the bottom. Tell students that they will put the tips of their filter strips into the mystery liquid. Ask, What do you think might happen when you this? 

  3. Have each student write his or her initials at the top of his or her filter paper strip. Then, have students place the bottom tips of their strips into the liquid and fold the strips over the side of the beaker so that they stay upright. Student’s also may tape the strips onto a pencil, and rest the pencil across the top of the cup. 

    Note: The activity will work better if the strips are not pressed against the sides of the beakers.

  4. Have students observe the beakers and strips for 5–10 minutes. As color begins to rise up the strips, ask, What is happening?

Funded by the following grant(s)

National Institute of Environmental Health Sciences, NIH

National Institute of Environmental Health Sciences, NIH

The Environment as a Context for Opportunities in Schools
Grant Numbers: 5R25ES010698, R25ES06932

Houston Endowment Inc.

Houston Endowment Inc.

Foundations for the Future: Capitalizing on Technology to Promote Equity, Access and Quality in Elementary Science Education