Science Exploration- Color Changing Cabbage
Red cabbage has some unique properties that allow it to change color in the presence of other substances. In this experiment, we will show you how to make the red cabbage solution and also explore its color changing properties!
Mess Level: Medium
Here is what you need (to make the cabbage indicator solution):
• 2 Cups of Red Cabbage (finely chopped)
• Large glass container
• Hot Plate or Stove Top
• Adult Supervision!
Here is what you need (to test):
• Red Cabbage indicator solution
• Lemon Juice
• Baking Soda
• Antacid (Tums or Rolaids)
• 4-6 small bowls or cups (you will want one for each testing ingredient)
• Safety Glasses
• Paper Towels
What to do (to make the cabbage indicator solution):
1. Before starting the activity, make sure you have adult supervision!
2. Place 2 cups of finely chopped red cabbage into a large glass container
3. Pour boiling water into the glass container and let it sit for at least 10 minutes. The color will start to leach out of the cabbage
4. When the liquid has turned a reddish-blue color, use a strainer to filter out the plant material from the liquid
5. Pour the liquid into a container and label it. This is your cabbage indicator solution.
6. You can store your cabbage indicator in the fridge in a screw top jar for up to a week.
What to do (to test):
1. Make labels for each of your testing ingredients (lemon juice, antacid, vinegar, baking soda)
2. Pour ½ cup of the cabbage indicator into small, individual cups or bowls
3. Place your labels next to each of the containers and add the corresponding testing ingredient into the cabbage indicator
4. Observe the changing colors
How did that work?
Red cabbage juice is considered to be an indicator because it shows us something about the chemical composition of other substances. Red cabbage contains a chemical called anthocyanin that changes color when it is mixed with an acid or a base.
When the liquid is a red or purple color it means that it is more acidic. When the liquid is a blue, green, or yellow color it means that the liquid is more basic.
You can conduct a neutralization experiment using a cabbage juice indicator. First, add an acidic solution such as vinegar or lemon, then juice until a reddish color is obtained. Add baking soda or antacids to make the mixture more neutral.
Try experimenting with other household substances like orange juice, Coca-Cola, ammonia, or milk to see what colors they turn the cabbage indicator solution. Based on the color they turn the cabbage indicator, try to determine which are acids and which are bases.