REQUIRED PRACTICAL 6: PHOTOSYNTHESIS

• Aquatic plants produce visible bubbles of oxygen gas into the surrounding water when they photosynthesise, these are counted as a measure for the rate of photosynthesis
• METHOD

  • lie the lamp on its side, place beaker of water in front of it to act as a heat shield
  • fill boiling tube with sodium hydrogen carbonate solution
  • put pondweed into tube with cut end at the top, push it down with glass rod
  • attach tube to clamp stand right behind the beaker
  • leave for 5 minutes
  • start stopwatch and count bubble number produced in one minute
  • repeat to gather mean data
  • repeat at different distances for range of results
• CALCULATE THE LIGHT INTENSITY

  light intensity = 1 / DISTANCE(^2)

  units in cm(-2)