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Acidic and Basic Test

Suggested Grades

3+

Objective

Students will be introduced to acidic and basic liquids through this simple test.

Materials

  • clear plastic cups
  • a head of purple cabbage coarsely shred.
  • spoons
  • paper towels
  • *safety glasses
  • white vinegar
  • ammonia
  • water

Method

Can do this activity as a demonstration or in class groups. Take extra care with the ammonia, though.

  • Boil the shredded cabbage in a 1/2 a pot of water for about ten minutes. Strain and refrigerate until ready to use.
  • Fill cups about half way with each liquid.
  • Add one teaspoon of the boiled cabbage to each glass. What happened?

    Cabbage should change colour:

    • vinegar - red - acid
    • ammonia - green - base
    • water - purple - neutral
  • Based on these colour changes, try to predict whether other liquids are acidic or basic, then add the boiled cabbage to find out. Extension: Make your own indicator paper.
  • Soak paper towels or white coffee filters in purple cabbage juice.
  • Let dry and cut into strips. The strip should change colour according to the type of liquid it's dipped into.

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