Red Cabbage pH Indicator

In this lab based activity students actually make their  own pH indicator solution with red cabbage juice! Red cabbage juice contains a natural pH indicator that will change colors according to the acidity of the solution. Red cabbage juice indicator is easily made  and  exhibits a wide range of color that  can be used to make their own pH paper strips. An instructional video is attached. A great lab using red cabbage juice as a pH indicator that shows the pH of a substance with a color change. This activity does involve advanced preparation time for the cabbage juice. Activity closely tied to GLE and could serve as an extension activity.

Lesson Variations

Blooms taxonomy level: 
Applying

Helpful Hints

Materials You Will Need:

  • Red cabbage
  • Blender or knife
  • Boiling water
  • Filter paper (coffee filters work well)
  • One large glass beaker or another glass container
  • Six 250 mL beakers or other small glass containers
  • Household ammonia (NH3)
  • Baking soda (sodium bicarbonate, NaHCO3)
  • Washing soda (sodium carbonate, Na2CO3)
  • Lemon juice (citric acid, C6H8O7)
  • Vinegar (acetic acid, CH3COOH)
  • Cream of tartar (Potassium bitartrate, KHC4H4O6)
  • Antacids (calcium carbonate, calcium hydroxide, magnesium hydroxide)
  • Seltzer water (carbonic acid, H2CO3)
  • Muriatic acid or masonry's cleaner (hydrochloric acid, HCl)
  • Lye (potassium hydroxide, KOH or sodium hydroxide, NaOH)

References

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