Grade 4- Iodine test for starch

In the course of the chapter "Plants prepare food" the students learnt that, food prepared by the plants is a type of sugar called glucose. The excess glucose is stored in various parts of the plant e.g. roots, stem leaves, etc as starch. To test the presence of starch in various food items the students carried out an experiment. A drop of iodine solution with the help of a dropper was put on food items like biscuits, onion, cabbage, idili etc.  The students observed that these food items containing starch showed a change in colour ( dark blue spot) and those like cabbage and onion showed no change as they do not have starch.  Later they noted down the same in their work books. This interactive session helped them understand iodine test for starch.