When two substances chemically react, a new substance is produced. One indication that a new substance has been produced is a color change. The universal indicator is a chemical that changes color in the presence of certain levels of acids and bases. Acids turn the indicator red, pink, orange, and yellow, while bases turn the indicator green, blue, and purple (fuchsia). The purple color may look more like a deeper pink, as compared to the pink you will see when the solution is acidic. Phenolphthalein solution is also an acid/base indicator; however, this substance will only change color in the presence of a base.