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Light is necessary for photosynthesis
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Light is necessary for photosynthesis • Pls subscribe our channel • / @scienceprojects7130 • Experiment: • 1.Take a potted plant having green leaves and place it in a completely dark place for about 48 hours to destarch its leaves. • During photosynthesis plants form starch in the leaves. Destarching a plant involves preventing photosynthesis, usually by keeping the plant in the dark for 24 to 48 hours until the starch is used by the plant for their food and energy. • 2. Take a thin strip of black paper and wrap it on one leaf on both the sides so that sunlight may not reach it from both the sides. • 3. Cover the leaf partially so that the remaining part of the leaf remains exposed to sunlight. • 4. Keep this potted plant with partially covered leaf in bright sunlight for a few hours. • 5. After few hours pluck the partially covered leaf from the plant and remove the black paper. • 6. Put the leaf in boiling water for a few minutes. • 7. Now boil the leaf in alcohol over a water bath. In this way, we get a decolourised leaf due to removal of chlorophyll. • 8. Wash the decolourised leaf with water to remove any alcohol present. • 9. Put the leaf on a white paper and pour iodine solution over the leaf and observe any change in colour. • 10. The middle part of leaf which was covered with black paper does not turn blue-black on adding iodine solution showing that no starch is present in the middle part of the leaf. • This is because sunlight could not reach the covered part of the leaf due to which the leaf could not do photosynthesis to produce starch. • 11. The uncovered part of leaf which was exposed to sunlight turns blue-black on adding iodine solution showing that starch is present in this part of leaf. • This means that the part of leaf which was exposed to sunlight could do photosynthesis to produce starch. • We conclude that sunlight is necessary for photosynthesis to produce food like starch. • Thanks for watching our video. • Science Projects • Science Experiments • Smart Scholar
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