Goldenrod Paper

    Kids, learn how to use a special color-changing paper to develop a hidden message! Certain brands of goldenrod (golden yellow) paper contain a special dye that turns bright red in solutions that are basic like ammonia or baking soda. The paper turns back yellow with an acid like vinegar or lemon juice.

    Please note:  All chemicals and experiments can entail an element of risk, and no experiments should be performed without proper adult supervision.

    You will need some sheets of goldenrod paper (available on-line at several sites or craft stores), cotton balls, household ammonia from the grocery store, safety glasses, and a candle.

    1. Place a piece of goldenrod paper on the table. Make sure that table is clean and the work surface is dry.

    2. Place a drop of water on one of the corners of the paper. Does anything happen?

    3. Fill a jar with a small amount of ammonia water. Dip in a cotton ball and wipe it across the top portion of the goldenrod paper. Does anything happen?

    4. As you continue to wipe designs on the top half of the goldenrod paper, notice that the paper does not stay red forever. What is causing the paper to change back to yellow?

    5. Use the old piece of wax candle to write a secret message (such as “Chemistry is Cool!”) across the bottom half of the paper.

    6. Wipe the cotton ball with ammonia water across the secret message to see what develops.

    How does it work?

    Goldenrod paper's yellow color is from a dye that is found in turmeric powder, a deep orange-yellow spice. Turmeric contains 5% essential oils and 3% curcumin (another name for turmeric is curry).   It is the active substance of turmeric and it is also known as Natural Yellow 3; the full chemical name is (hang on!): (1E,6E)-1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione (a polyphenol).

    The ammonia on the cotton ball is a base and causes the dye in the special goldenrod paper to change color. You probably noticed that the red color fades over time and the paper eventually changes back to its original yellow color. Why? Carbon dioxide in the air reacts with ammonium hydroxide to make ammonium carbonate, which is neutral. If you use a stronger base like baking soda, the red message will not disappear in air. You will need to use a stronger acid like lemon juice or vinegar to change it from red to yellow. You can also use goldenrod paper as inexpensive pH paper to classify safe household products as being either acidic or basic.


    Kathleen Carrado Gregar, PhD, Argonne National Labs
    June 2009


    References: (search “goldenrod”); this link also has a video.
    Carl Ahlers - Prof Bunsen Science (