Chemistry experiments: Briggs-Rauscher reaction or Iodine clock
When several chemicals are mixed – hydrogen peroxide, iodic acid, manganese(II) sulfate, sulfuric and malonic acids, and starch – a chain of complex reactions is triggered. As a result, the solution periodically changes color from colorless to amber, and then to dark blue. This occurs due to the formation and disintegration of iodine complexes with starch.