Make Your Own pH Paper

You can make your own pH paper to test the acidity of common chemicals using a coffee filter and one of several common plants. One way is to prepare red cabbage pH indicator, soak a coffee filter in the indicator, allow the paper to dry, then cut it into test strips. If you happen to have a holiday poinsettia, you can use some of the red bracts to make poinsettia pH paper. Once you have test strips, you can use a toothpick or cotton swab to apply a test chemical. The reactions from household chemicals of known pH can help you evaluate unknowns.
Photo: Emily Roesly