Primary School in Chalin eTwinning ClubRED CABBAGE PH INDICATOR Ania & Bartek Class 6
THE PURPOSE OF THIS EXPERIMENT IS TO SHOWHOW TO MAKE YOUR OWN PH INDICATOR USING CABBAGE JUICE
RED CABBAGE JUICE CAN BE USED TO TEST THE PH OF COMMON HOUSEHOLD CHEMICALS. RED CABBAGE JUICE CONTAINSA NATURAL PH INDICATOR THAT CHANGES COLORS ACCORDING TO THE ACIDITY OF THE SOLUTION.
To make our own red cabbage juice indicator we need: * red cabbage * blender or knife * boiling water Procedure Chop the cabbage into small pieces until you have about 2 cups of chopped cabbage. Place the cabbage in a large beaker or other glass container and add boiling water to cover the cabbage. Allow at least ten minutes for the color to leach out of the cabbage. Filter out the plant material to obtain a red-purple-bluish colored liquid. This liquid is at about pH 7. Ania and Bartek prepared pH indicator a day before their experiment.
Set out 5 glasses, side by side.Fill each glass half full with cabbage juice.
Add a lemon to the glass of cabbage juice We noticed the color changed to red, which indicated that lemon juice is classified as an acid.
Add a little vinegar to the glass of cabbage juice We noticed the color changed to red, which indicated that vinegar is classified as an acid.
Add a teaspoon of laundry detergent to the glass of cabbage juice We noticed the liquid turns green, indicating that this chemical is a base.
Add a teaspoon of oven cleaner to the glass of cabbage juice We noticed the color changed to green, which indicated that the oven cleaner is classified as an base.
Add a teaspoon of alka-prim tablets to the glass of cabbage juice We noticed the color changed to green, which indicated that alka-prim tablets are classified as an base.
DURING OUR EXPERIMENT THE PURPLECABBAGE JUICE TURNED RED WHEN IT WAS MIXED WITH SOMETHING ACIDIC AND TURNED GREEN WHEN IT WAS MIXED WITH SOMETHING BASIC. REDCABBAGE JUICE IS CONSIDERED TO BEAN INDICATOR BECAUSE IT SHOWED US SOMETHING ABOUT THE CHEMICALCOMPOSITION OF OTHER SUBSTANCES.
RED CABBAGE CONTAINS A WATER-SOLUBLE PIGMENT CALLED ANTHOCYANIN THATCHANGES COLOR WHEN IT IS MIXED WITH AN ACID OR A BASE. THE PIGMENT TURNS RED IN ACIDICENVIRONMENTS WITH A PH LESS THAN 7 AND THE PIGMENT TURNS BLUISH-GREEN INALKALINE (BASIC) ENVIRONMENTS WITH A PH GREATER THAN 7.