Experiment to show that Light is essential for Photosynthesis:
Requirements: A potted plant with green leaves, Black paper, Alcohol,
Iodinesolution, and clips, (the plant should kept in dark for a long time
before experiment). .
Procedure: Cover both side of a leaf with black paper and clip so
that Sunlightcannot reach inside. Then let the pot with the plant be kept in Sunlight.
After one hour tear the leaf off and boil in alcohol so that the leaf becomes
chlorophyll free. Now let the leaf be immersed in iodine solution.
Observation: On taking out from the iodine solution it will be seen
that all thearea except the covered area became blue (deep violet or black)
Conclusion: Carbohydrate react with iodine solution turns to blue
(deep violetor black). Sunlight did not reach the area covered with black
paper; photosynthesis did not occur there, that is carbohydrate did not
produce. As carbohydrate did not produce there the area did not turn blue (deep
violet or black). Thus it is proved that Sunlight is essential for
photosynthesis so to say for manufacture of carbohydrate.