Thank you for sharing Mystery Ink with us Mr. G.
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?
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)
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!