Testing for Acids

Teacher had a red cabbage in school with her.

In a way it was a fortune telling cabbage (It could tell whether things were acids or not).  We know that acids are bad for our teeth and that we should wash our teeth well after eating or drinking acidic things.

We put a leaf of the red cabbage into hot water and let it cool.

The cabbage water turned a light purple colour.

We filled lots of little cups with this cabbage water, and then added different liquids like vinegar, orange juice, lemon juice, bread soda, bleach, shampoo and conditioner.  Before testing each item we said “Cabbage water, cabbage water, is the ____ an acid or not?”  Each time the cabbage water was able to give us a good answer.

We noticed that acids turned the cabbage water pink, alkalis (like bread soda) turned the cabbage water light blue and bleach takes all the colour from the cabbage water.

Having a red cabbage is a handy way to test for acids.