Write an Experiment That Shows That Sunlight Is Important for Photosynthesis?

The experiment using a potted plant and iodine test proves that sunlight is essential for photosynthesis.

Materials Required

• A healthy potted plant
• Black paper
• Scissors and pins
• Iodine solution
• Alcohol and test tubes
• Beaker and hot water

Procedure

1. Keep the potted plant in a dark room for 24–48 hours to remove stored starch.
2. Cover one leaf partly with black paper and expose the plant to sunlight for a few hours.
3. After exposure, remove the leaf and boil it in water for a few minutes.
4. Then boil it in alcohol to remove chlorophyll, making the leaf pale.
5. Dip the leaf in warm water again to soften it.
6. Add iodine solution to the leaf.

Observation

The part of the leaf exposed to sunlight turns blue-black in color (presence of starch), while the covered part remains yellowish-brown.