What do you do after returning the rest tube to the water bath?

After returning the test tube to the water bath, wait 30 seconds then use the stirring rod to transfer one drop of solution to a well in the spotting tile which contains iodine And the iodine should turn blue-black showing that starch is present Take a sample every 30 seconds until the iodine remains orange - which shows that starch is no longer present in the solution and the reaction is completed. Then record the time it took for the iodine to remain orange Finally repeat this reaction several times using different pH buffers for example pH 6, 7 and 8