Materials List: Should I Drink That?

Each group needs:

  • 8 paper cups, to hold test samples of deionized water, purified water, school tap water, salt-water solution, and each student's sample of tap water brought from home
  • ~400 ml deionized water (200 ml for test sample, 200 ml to make salt-water solution), such as chemical grade, 1 gallon bottle (CAS 7732-18-5) at; some company and university research labs are willing to give teachers some deionized water for free
  • ~200 ml purified water, such as 1 gallon bottle at grocery stores or Walmart
  • ~200 ml school tap water
  • ~2g salt and 200 ml deionized water (purified water works, too)
  • ~200 ml sample tap water from home, per student
  • LED-conductivity tester, such as the one in Figure 1-left, made by the teacher from 2 AA batteries in a battery holder with switch, breadboard and LED light, wire, alligator clips and electrical tape, mounted on sturdy cardboard; connect everything as shown on the Testing Equipment Setup Visual Aid (which also provides website sources for example materials)
  • electrical conductivity meter, see Figure 1-middle, such as HM Digital AP-2 AquaPro Water Quality Electrical Conductivity Tester at
  • multimeter (includes two test probes), see Figure 1-right
  • a map of your local school district divided into ~5 distinct areas; see the Procedure section for details
  • extra 200 ml purified water in cups or squirt bottles, for rinsing testing equipment between samples
  • paper towels, for drying rinsed testing equipment
  • Should I Drink That? Worksheet, one per person
  • Lab Equipment Testing Instructions, one per group
  • (optional) tray to hold the water samples in cups, to contain any spillage
  • (optional) calculators, for calculating averages

To share with the entire class:

  • sink and drain, for source of school tap water and disposal of water samples
  • marker or tape and pen, for labeling cups to identify water samples
  • (optional) capability to show students a four-minute online video