Generates 6 test tubes and that each one is added a drop of Lugol

generates 6 test tubes and that each one is added a drop of Lugol ,and each test tube has a different food , in the first test tube a piece of banana is added to the second a piece of potato or potato to the third a few grams of sugar to the fourth a small piece of bread to the fifth a few grams of rice to the sixth a small piece of noodle , each tube with its respective chemical reaction , more noticeable with those that have starch all straight without errors