Sulfuric acid is corrosive and toxic
Oxalic acid is caustic
Chemicals and Solutions:
Oxalic acid/sulfuric acid solution
two ungraduated cylinders
Fill both cylinder 1/4 full of KMnO4 solution. Fill one of the cylinders with oxalic acid/sulfuric acid solution and the other with DI water.
Solution changes from Purple to Rose to Orange-brown to faint yellow to colorless over 4-5 minutes.