A beautiful demonstration to introduce students to acid–base indicators. The dye used in this special goldenrod paper acts as an acid–base indicator. When the paper comes in contact with a base, it changes from goldenrod to a dark red. Write hidden messages, splash fake blood or amaze your students with this great introduction to acids and bases. Instructions describe what bases to use and how to perform this demonstration so the paper is reusable. The best part is that carbon dioxide in the air will slowly change the red color back to goldenrod—just in time for your next class!
Concepts: Acid–base indicators, equilibrium. Time Required: 15 minutes Materials Provided: 100 sheets of reusable goldenrod paper.