Chemical Traffic Light experiment is particular reaction classified as a chemical clock rotation. It take place when the concentrations of products and reactants can change periodically. This periodic change can occur following rapid changes. Unlike most chemical reactions,the products spontaneously change back. The experiment involves changing colors with an indicator. Indigo Carmine in an alkaline solution of glucose. The alkaline solution of Glucose is poured into a solution of indigo carmine make a gradual change color: First blue became Green – Red – Yellow.