Materials:
red cabbage
cooking pot
small containers with lids
funnel
eye dropper
coffee filter
various liquids to test - lemon juice, liquid soap, water, vinegar, milk, washing soda
Procedure:
Cut cabbage into small pieces. Put in saucepan and add enough water to cover the cabbage. Bring to a boil. Turn off heat and let stand for about an hour. Drain off cabbage juice into a jar. Dip strips of coffee filter into the juice and let dry. This will be the indicator paper.
Fill labeled containers with different substances to about 3/4ths full. Dip strips into liquid, or use eye dropper to put liquid on strips.
The indicator reacts with the liquid and changes color according to the acidic or alkali level. If the liquid is an acid, the paper will turn red or pink, If the liquid is an alkali, the paper will burn blue or green. Yellow indicates a neutral substance.
We also poured cabbage juice into the jars. This made it easier for the students to see and compare the colors.
We had also used full sized coffee filters that were dipped with cabbage juice and made a picture by using a small paint brush to create a picture with different colors.
