Purpose:
After reviewing the acid/base tutorial you will apply this understanding by creating your own pH indicator strips using coffee filters soaked in purple/red cabbage juice. Special molecules in the juice react to pH by changing shape (which translates into a color change).

Materials: Purple/Red cabbage Small Pot Coffee filters Various acid/base solutions to test

Procedure:

• Cut the cabbage into small pieces and place in the pot with just enough water to cover
• Boil the mixture until the liquid turns dark blue-purple
• Soak the coffee filters in the juice for 20 minutes, lay out on a plastic tray or wax paper and let dry
• Get known solutions to test. e.g. white vinegar, soda, lemon or orange juice, detergent in water, baking soda in water (for pH values see acid/base tutorial).
• Place a few drops of the test solutions on separate spots of the indicator paper. Basic solutions should change the paper greenish and acids should cause pinkish coloration.
• Test an unknown solution with your pH color wheel (provided by the teacher or have a friend pick a drop of one of the knowns to identify).

Conclusion:
Finally, update your website with the details of this lab experience including a short summary (describe anthocyanins) and results! The instructor will grade this lab web entry according to this rubric.