This clock reaction uses sodium, potassium or ammonium persulfate to oxidize iodide ions to iodine. Sodium thiosulfate is used to reduce iodine back to iodide before the iodine can complex with the starch to form the characteristic blue-black color. Follow us 👉 @sciencefunn for more science and daily facts.🤓 Enjoy the rest of your day.😇 This content has been shared using Instagram Remix/Sequence feature from the content owner @rebecca1227_ via @pubity | Science Is Fun For Everyone