MR. G DOES MYSTERY INK

We always love a visit from our favorite scientist and today was no exception!
​Thank you for sharing Mystery Ink with us Mr. G.

Problem: What happens to golden-rod paper when you draw on it with baking soda and water?

Materials: Q-tip, water, baking soda, vinegar, cup,  golden-rod paper, stir stick, teaspoon

Procedure: Get a piece of golden-rod paper and place it on a dry desk.  Fill a small cup half way with water.  Dip in a Q-tip and then touch it to a corner of the golden-rod paper.  Now add 1/2 teaspoon of baking soda to the water and stir.  Dip the Q-tip into this mixture and then write the first letter of your name on the golden-rod paper with the Q-tip.  What happens? 
If you have more time...get another small cup.  Fill it half way with water.  Add 1/2 teaspoon of vinegar and stir.  Dip the Q-tip and trace over your letter with it.  What happens?

Hypotheses:
A. The letter you wrote will glow in the dark. (5)
B. The letter will change color to a bright orange. (2)
C. The mixture will make a crackling noise on the paper. (3)
D. The mixture will burn a hole in the paper in the shape of the letter you wrote. (7)

Conclusion: The letter will change color to a bright orange.
Vinegar and baking soda are opposite chemicals.  Vinegar is an acidic chemical.  Baking soda is a basic chemical.  Golden-rod paper is an acid-base indicator.  The paper reacts to the base baking soda and turns a bright orange.  When you mix baking soda and vinegar they cancel each other out; they become neutral like water.  When we traced over the letter with the vinegar the base becomes neutralized and the the writing is erased by the vinegar!  So cool!