Traffic light colors
Chemicals: glucose, sodium hydroxide, indigo
Solution A: 14 g glucose in 700 ml water
Solution B: 6 g of sodium hydroxide in 200 ml water
Solution A is heated to 35 ° C. and 0.1 g of indigo carmine. The solution is blue. Addition of solution B, the color changes to green. During the 30s, the color changes to red, which after 3 minutes, turn yellow.