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.

Standards & Objectives

Academic standards
GLE 0706.2.1
Extend understandings of addition, subtraction, multiplication and division to integers.
GLE 0807.9.9
Explain the basic difference between acids and bases.
 
Alignment of this item to academic standards is based on recommendations from content creators, resource curators, and visitors to this website. It is the responsibility of each educator to verify that the materials are appropriate for your content area, aligned to current academic standards, and will be beneficial to your specific students.
 

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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