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Grades 6, 9, and 10 Beginner About 20 min Version 1 Awaiting review Premium

How clean is our water? Testing water samples

Water from different places can look and behave very differently. Looking closely shows particles of mud or algae. Universal indicator shows whether water is acidic, neutral or basic. The soap test shows whether water is hard. None of these tests can show germs, which need a microscope or a laboratory test, so even clean-looking water may not be safe to drink.

What you will learn

  • Compare water samples by appearance, pH and hardness.
  • Use distilled water as a control.
  • Suggest possible causes of poor water quality and explain the limits of simple tests.

Before you start

  • Know how to use universal indicator and the soap test.

Materials

  • Tap water, well water, river water, pond water and distilled water
  • Universal indicator
  • Soap solution

Equipment

  • 6 test tubes in a rack

Procedure

  1. Add a water sample to a test tube and look at it closely.
  2. Add universal indicator, stir, and read the pH.
  3. In another tube, add soap solution to a sample, shake (stir), and look at the lather.
  4. Test as many samples as you can and record your results in a table.

How this simulation is simplified

  • Each sample is shown with typical properties for its source. Real samples vary from place to place.
  • These simple tests cannot detect germs or harmful dissolved chemicals.