Chemical Magic

• Materials

  • A few leaves of red cabbage
  • A blender
  • A strainer
  • Plastic cups
  • Water
  • Some household products described in each section

Experiment

Easy Method: Red Cabbage Jiffy Juice

Just follow the directions on the Red Cabbage Jiffy Juice bottle to make a big pitcher of "indicator" solution.
Stinky Method: Make Your Own Cabbage Juice

1. Peel off six big cabbage leaves and put them in a blender filled half full with water. Liquify it!
2. Pour the purplish cabbage liquid through a strainer to filter out all of the big chunks of cabbage. Doesn't cabbage juice smell great?
3. Save the liquid for the experiments to follow.

Regardless of which method you used to make your "indicator" solution, try this...

1. Set out three glasses, side by side against a white piece of paper.
2. Fill each glass half full with cabbage juice.
3. Since you know that vinegar is an example of an acid, add a little vinegar to the first glass of cabbage juice. Stir with a spoon and notice the color change to red, which indicates that vinegar is classified as an acid.
4. In the second glass, add a teaspoon of washing soda or laundry detergent. Notice how the liquid turns green which indicates this chemical is a base. Keep these two glasses of red and green liquid for future reference.
5. Try adding your own "test" substances to a small amount of cabbage juice and note the color change to determine if something is an acid or a base.  Orange juice, lemonade, milk, salt, ammonia, or soap are some suggestions. 

How Does It Work?

Some substances are classified as either an acid or a base. Think of acids and bases as opposites. Scientists can tell if a substance is an acid or a base by means of an indicator. An indicator is typically a chemical that changes color if it comes in contact with an acid or a base.
As you can see, the purple cabbage juice turns red when it is mixed with something acidic (an acid), or green when it mixes with something basic (a base). In the previous experiment, the vinegar was the acid and the laundry detergent was the base. Remember that an acid is the opposite of a base. Red cabbage juice is considered to be an indicator because it shows us something about the chemical composition of other substances. This is just one of many indicators that are available to scientists. Some indicators start out colorless and turn blue or pink, for example, when they mix with a base. There are hundreds of different types of indicators available to scientists depending on the type of substance that they are testing. If there is no color change at all, the substance that you are testing is probably neutral, just like water.

Additional Info

WARNING: Making your own red cabbage indicator is guaranteed to drive everyone out of your house because it stinks!