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CCSS.RI.5.10 |© http://www.englishworksheetsland.com

A Chemistry Experiment               

     

1. What is the purpose of this experiment?  2. In this experiment, which of the following is the 

acid?  

A. water B. vinegar C. baking soda 

 3. Why do the flowers change color?       4. What is litmus paper?    

Litmus paper is an acid-base indicator, a paper that changes color depending on whether or not it comes into contact with an acid or a base. Many plants in nature are also acid-base indicators. This is because most plants are slightly acidic or alkaline themselves, so they change color when mixed with something that has the opposite ph.

You Will Need the Following Materials:

Collect three of more different kinds of flowers of different colors (red, pink, orange, blue, purple, etc.). Good flowers to test include geraniums, hydrangeas, morning glories, poppies, tulips, violets, petunias, pansies, roses, and hibiscus flowers.

White Vinegar A spoon for each flower 5 or more clear plastic cups. Baking soda Water A marker

Take These Steps: 1. Label one plastic cup "acid" and another “base". Add half a cup

of white vinegar to the acid cup. Mix a few teaspoons of baking soda with half a cup of water and pour it into the base cup.

2. Choose one of your flowers. Write down what kind and color of flower it is. Crush its petals into a pulp. Divide it into three empty cups. Add a few drops of water to each one.

3. Use a spoon to add a few drops of acid to one cup. Use a different spoon to add a few drops of base to another.

4. Now compare the flowers in the three cups. If the flower is an acid-base indicator, you will know it immediately because the flower petals in one of the cups will change colors. A red flowers will turn bluish or greenish in a base, and become more vividly red in an acid. A blue flower will turn red or pink in an acid, and a brighter blue in a base. Take notes on the results.

5. Using clean cups each time, repeat the experiment to test each kind of flower. Take notes each time.