Homemade pH indicator

Materials

1. Bowl

2. 1/4 cup water

3. 1/4 cup vinegar

4. 1/2 teaspoon turmeric

5.1/2 cup rubbing alcohol

6.1 teaspoon baking soda

7.Clear drinking glass

How Do I Do It

1. Combine the turmeric and rubbing alcohol in the bowl.

2. Combine the baking soda and water in the glass.

3. Pour a sufficient amount of the turmeric/alcohol combination into the glass to effect a color change. Observe the reaction. What color was produced?

4. Pour the vinegar into the glass.

What's Going On? 

Adding the pH indicator to the basic solution should have turned it red. Adding an acid (vinegar) made it foam and revert to its original yellow color.