The anthocyanin in cabbage is used to demonstrate pH differences in household chemicals.
- Purple Cabbage (other fruits & vegetables which work well are radishes, beets, blueberries, grape juice. Note: Purple cabbage offers a wide range of colors and is probably the best example if a single indicator is to be used)
- array of buffers pH 2-13
- household items
- baking powder
- To make cabbage indicator simply place several cabbage leaves in a blender, add water and puree.
- Add indicator to each cylinder in the array of buffers.
- The pH of household chemicals can be tested by adding indicator and comparing the color produced to the buffer array.
Note: The indicators tend to deteriorate on standing and should be either freshly prepared or refrigerated if necessary for a day or two. I have frozen them in ice cube trays and they have kept well for several weeks. The indicator is an anthocyanin.
|1-3||pink||7-up, vinegar, asprin, lemon juice|
|10||green||sodium bicarbonate, Rolaids|
|12 & up||yellow||ammonia, drano|