cp light & RoP

• We will need

  • sealed 100ml flask filled with water at room temperature
  • gas syringe
  • pondweed
  • lamp
  • 1m ruler
• 1. The apparatus is set up and placed 15cm away from the lamp which gives off white light. Sodium hydrogen carbonate can be added to the water to ensure the plant has enough CO2
• 2. Leave the pondweed to photosynthesise for 10 minutes
• 3. As it photosynthesises, the oxygen released will collect in the gas syringe, this gives you an accurate measure of the volume of oxygen produced
• 4. This whole experiment is then repeated with the pondweed at a different measured distance from the lamp
• Any variables that could affect the experiment need to be controlled

  • temperature
  • CO2 concentration
• The rate of oxygen production can be calculated by,

  volume produced ÷ time taken