Materials List: Protect Your Body, Filter Your Water!

Each group needs:

  • 1.5 foot (.46 m) plastic tubing or PVC pipe with 1.5 inch (3.81 cm) or greater inner diameter; available at hardware stores (see Figure 1, which shows an example tube that is longer than 1.5 feet; it is recommend to cut tubes to 1.5 feet to avoid difficulties in removing filter materials)
  • 2 250-ml beakers
  • 50-100 ml chlorinated water; this 200 ppm solution is prepared by the teacher using Clorox┬« germicidal bleach; see instructions in the Procedure section
  • 50-ml graduated cylinder
  • plastic spoon, to load sands and activated carbon
  • sieve, to separate small materials
  • lab safety gloves, one pair per student per day, such as disposable nitrile gloves available at
  • lab book or notebook, one per student; alternatively, have students record all necessary information throughout the activity on blank sheets of paper and staple them together to serve as a lab "book" for the activity
  • safety goggles, enough so that each student in a team can wear goggles while handling and testing the chlorinated solution
  • Engineering Design Report Scoring Rubric, one per student
  • Claim-Evidence-Reasoning Graphic Organizer, two per student

To share with the entire class:

  • activated carbon, either granules or pellets; for cleanup, pellets are easier to separate with a sieve at activity end; see material life expectations note, below
  • filter media, such as cotton balls, fish filter media, carbon infused filter media, 50 micron felt pad, cheesecloth, cotton cloth or whatever is available
  • fine-grained sand
  • (for teacher use only!) Clorox┬« germicidal bleach; used to make a chlorinated water solution; 2 teaspoons bleach per gallon of water
  • pitcher or other container large enough to hold a gallon of water, for preparing the chlorinated water
  • "free" and total low-level chlorine water quality test strips, such as Hach's "Free & Total Chlorine Test Strips, 0-10 mg/l," 50 strips, 0-10 ppm, at
  • sanitizer-strength chlorine test strips, such as LaMotte's "4250-BJ sanitizer strength chlorine test strips," 200 strips, 0-200 ppm, from Cole-Parmer at
  • stopwatch
  • sink, tap water, soap, towels

Note: A pound of activated carbon can remove 200 ppm chlorine from 843 gallons, as calculated from Thus, a supply of activated carbon is reusable for several years of experiments.