ActivityAim: To demonstrate that sunlight is necessary forphotosynthesisbrown, while che part of the leaf exposed tosunlight turns blue-black.Explanation: The blue-black colour of theexposed part of the leaf is due to the presence ofstarch. The absence of starch in the coveredof the leaf results in the yellow-brown colour.To be demonstrated by the teacherpartThings required: A pocted plant with greenleaves, chick black paper, spirit, burner, test tube.beaker, forceps, iodine solution, and alcoholMethode1. Keep the potted plant in dark for two days.2 Cover the middle part of a leaf of this plantwith black paper so that it does not get anysunlighe3 Keep the plant in the sunlight for a day.4Perform the iodine test on the leaf (asdemonstrated in the first activity).Observation: You will notice that the part of theleaf that was deprived of sunlight turns yellow-Conclusion: The absence of starch shows thatphotosynthesis did not take place in the part ofleaf that was deprived of sunlight. This shows thatthe sunlight is necessary for photosynthesis.​