ACID/BASE INDICATORS

ILENE J. WAGNER                O. A. THORP
                               6024 W. Warwick 
                               Chicago, IL 60634
                               1-312-545-0169

OBJECTIVE:
     To show that plant extracts are indicators for acids and bases.
MATERIALS: 
     Flask/beaker
     Heater
     Filter & funnel
     Test tubes and test tube holder
     Eye dropper bottle
     Boiling chips
     10 ml graduate
     Alcohol/water/acetone
     An acid (vinegar)
     A base (baking soda solution)
     A quantity of various plant materials: beets, red cabbage, flowers, berries, 
       teas, etc. 

PROCEDURE: 
     Boil plant material in container with 40 ml of alcohol( or what ever solvent 
you use). NOTE:DO NOT USE ALCOHOL WITH OPEN FLAME OR FILAMENT Use boiling chips 
and a LOW heat to prevent spattering. 
     Filter material, using funnel and filter paper into eye dropper bottle or 
test tube.  Discard solid material. 
     Place 5-10 ml of base, acid, and water in separate test tubes.  Use your 
indicators to test for acid or base.  Use water as a control for the color. Note 
the color changes. 

STRATEGIES:
     Make indicators from various fruits and vegetables; use various indicators on 
several household products, food stuffs, cosmetics, medications, etc.  Use a chart 
that will show how much indicator is necessary to show color change, what the 
original color is and what change was seen. 
     Use filter paper with indicator on it, dried, to make your own litmus paper. 
                    

                                COLOR CHANGE
------------------------------------------------------------------------------
                                   ACID                     BASE
PLANT       | ORIGINAL COLOR | AMOUNT, DROPS | COLOR | AMOUNT, DROPS | COLOR
------------|----------------|---------------|-------|---------------|--------
Cabbage     |                |               |       |               |
------------|----------------|---------------|-------|---------------|--------
Beet        |                |               |       |               |
------------|----------------|---------------|-------|---------------|--------
Gladiolus   |                |               |       |               |
------------|----------------|---------------|-------|---------------|--------
Blueberries |                |               |       |               |
------------|----------------|---------------|-------|---------------|--------