tests/experiments

• Photosynthesis and Starch Testing

  Objective: To test for the presence of starch in a leaf.
• Photosynthesis and Starch Testing

  Procedure: 1) Remove a green leaf from a plant that has been exposed to sunlight. 2) Boil the leaf in water for 2 minutes. 3) Transfer the boiled leaf to a boiling tube with alcohol and place the tube in hot water to decolorize the leaf. 4) Remove the leaf, rinse it in hot water to soften it, and spread it on a white tile. 5) Add a few drops of iodine solution to the leaf. A blue-black color indicates the presence of starch.
• Photosynthesis and Starch Testing

  Observations and Discussion: • The alcohol decolorizes the leaf. • Boiling the leaf in water stops all chemical processes.
• Sunlight and Photosynthesis

  Objective: To find out if sunlight is necessary for photosynthesis.
• Sunlight and Photosynthesis

  Procedure: 1) Destarch a potted plant by keeping it in the dark for two days. 2) Cover parts of a leaf with black paper, expose it to sunlight, then test for starch.
• Sunlight and Photosynthesis

  Conclusion and Discussion: • Parts exposed to sunlight will turn blue-black with iodine, indicating starch formation. • This shows sunlight is necessary for photosynthesis.
• Chlorophyll and Photosynthesis

  Objective: To determine if chlorophyll is necessary for photosynthesis.
• Chlorophyll and Photosynthesis

  Procedure: 1) Destarch a variegated plant (one with green and white leaves) by keeping it in the dark for two days. 2) Expose it to sunlight, then test a leaf for starch. 3) Compare areas with and without chlorophyll.
• Chlorophyll and Photosynthesis

  Discussion: • Only the green parts (with chlorophyll) will turn blue-black, indicating that chlorophyll is essential for photosynthesis.
• Carbon Dioxide and Photosynthesis

  Objective: To find out if carbon dioxide is necessary for photosynthesis.
• Carbon Dioxide and Photosynthesis

  Procedure: 1) Destarch two potted plants by keeping them in the dark for two days. 2) Enclose one plant in a jar with soda lime to absorb CO₂. 3) Expose both plants to sunlight and test their leaves for starch.
• Carbon Dioxide and Photosynthesis

  Observation: • The plant without CO₂ will not produce starch, indicating that CO₂ is necessary for photosynthesis.
• Oxygen Production during Photosynthesis

  Objective: To find out what gas is produced during photosynthesis.
• Oxygen Production during Photosynthesis

  Procedure: 1) Use aquatic plants (like Elodea) and place them in water with sodium hydrogen carbonate. 2) Place the setup in sunlight and observe bubbles forming. 3) Test the gas with a glowing splint. If it reignites, oxygen is present.
• Oxygen Production during Photosynthesis

  Discussion: • Oxygen is given off during photosynthesis.