Acids and bases/Litmus paper

Many vegetable inks contain compounds which can be used for indicator paper.

Simple recipe for litmus paper:

1. Chop up some red cabbage
2. Add water to cover
3. Bring to a boil
4. Soak some blotting paper in the colored solution
5. Let the paper dry

Experiment with dipping the paper into a variety of common acids and bases. The paper will change color. Other intensely colored vegetables can also be used to make litmus paper.

See also:

• Acids and bases