GRAPE JUICE CHEMISTRY

Objective: To observe Grape Juice’s natural ability to detect acids and bases.

Materials:

• Grape Juice (Juicy Juice works very well, even though it's not 100% Grape Juice)
• Water
• Baking Soda
• Citric Acid Crystals (substitute vinegar if you don’t have citric acid crystals)
• Spoon
• 3 Clear plastic cups or glasses (10-12 ounce capacity)
• Paper Towels (optional, but handy in case of an overflow)
  

Procedure:

1. Pour about 1 inch of Grape Juice into an empty cup. Then add about an inch of water to the Grape Juice to lighten its color.
2. Pour about 1 inch of water into a different cup. Add a spoonful of Baking Soda to this water and stir until dissolved (or mostly dissolved).
3. Pour about 1 inch of water into your last cup. Add a spoonful of Citric Acid Crystals to this cup and stir until dissolved (or mostly dissolved). If you don’t have citric acid crystals, pour 1 inch of vinegar into the cup for this step.

KEEP TRACK OF WHICH CUP IS WHICH!

4. Pour the Baking Soda liquid into the Grape Juice and watch for a color change. Cool! Grape Juice detects chemicals that are “alkaline” or “bases” by turning darkish green-ish!
5. Next, pour the Citric Acid liquid into the darkish green-ish liquid. Whoa!!

Grape juice detects acids by turning a very light color! And as you may have noticed, baking soda and citric acid react in an exciting way also.

What’s Going On?

Grape juice, like many other natural chemicals, reacts when different types of chemicals are mixed with it. Cabbage juice is another example of a natural acid/base indicator.

Think and Talk About This:

Do you think toothpaste is an acid or a base? How could you find out? What other chemicals could you test with your Grape Juice indicator? With mom or dad’s permission & help, design and experiment and try it out!