This experiment is easy and fun for kids of all ages.
You Will Need:
- Blender (optional)
- Microwave (optional)
- Red cabbage
- Filter paper
Cut a red cabbage into pieces such that it will fit into a blender. Chop the cabbage, adding the minimum amount of water needed to blend it (because you want the juice as concentrated as possible). If you don’t have a blender, then use a vegetable grater or chop your cabbage using a knife.
Microwave the cabbage until it’s at the boiling point. You’ll see the liquid boil or else steam rising from the cabbage. If you don’t have a microwave, soak the cabbage in a small volume of boiling water or else heat the cabbage using another method. Then allow the cabbage to cool for around 10 minutes.
Filter the liquid from the cabbage through filter paper. It should be deeply coloured. Soak filter paper in this liquid. Allow it to dry. Cut the dry coloured paper into test strips.
Use a dropper or toothpick to apply a little liquid to a test strip. The colour range for acids and bases will depend on the particular plant. You can also construct a chart of pH and colours using liquids with a known pH so that you can then test unknowns. Examples of acids include hydrochloric acid (HCl), vinegar, and lemon juice. Examples of bases include sodium or potassium hydroxide (NaOH or KOH) and baking soda solution. Another way to use your pH paper is as a colour-change paper. You can draw on pH paper using a toothpick or cotton swab that has been dipped in an acid or base.
- If you don’t want coloured fingers, it is suggested to soak only half of the filter paper with the cabbage juice, leaving the other side uncoloured. You will get less usable paper, but you will have a place to grab it from.
- Many plants produce pigments that can be used as pH indicators. Try this project with some of the other common home and garden indicators.
NOTE: BEFORE USING ANY OF THE PRODUCTS LISTED PLEASE READ ANY SAFETY AND PRECAUTIONS TO THIS PRODUCT BEFORE USAGE.
PLEASE ALSO COMPLETE A PATCH TEST.
APC Pure does not accept any responsibility, this is a guide only.