Required Practical 6

• Pondweed can be used to measure the effect of light intensity on photosynthesis
• Experiment with pondweed and light

  1. Place source of white light at specific distance from pondweed

  2. Leave pondweed to photosynthesise for set time

  3. Oxygen released collects in capillary tube

  4. Use syringe to draw gas bubble alongside ruler and measure length

  5. Control any variables that could affect results

  6. Repeat twice with same light distance, calculate mean oxygen volume

  7. Repeat whole experiment with light at different distances
• Any variable that could affect the results should be controlled
• Repeat twice with the light source at the same distance and the mean volume of oxygen produced is calculated
• Repeat the whole experiment with the light source at different distances to the pondweed