RP06 - Photosynthesis

• What is the aim of the RP06 Photosynthesis practical?

  To investigate the effect of light intensity on the rate of photosynthesis in an aquatic organism (e.g., pondweed), measured by counting the number of oxygen bubbles produced per minute.
• What equipment is needed for the RP06 Photosynthesis practical?

  (Group 1: Basic Setup)

  Boiling tube, Freshly cut 10 cm piece of pondweed, Light source, Ruler
• What mnemonic is used to remember the equipment for Group 1: Basic Setup (RP06)

  "Big Frogs Leap Regularly"
• What equipment is needed for the RP06 Photosynthesis practical?

  Group 2 (Timing and Support)

  Test tube rack, Stopwatch
• What mnemonic is used to remember the equipment for Group 2: Timing and Support (RP06)

  "Timely Rest"
• What equipment is needed for the RP06 Photosynthesis practical?

  Group 3 (Chemical and Handling)

  0.2% sodium hydrogen carbonate solution, Glass rod
• What mnemonic is used to remember the equipment for Group 3: Chemical and Handling (RP06)

  "So Great!"
• What is the first step in the RP06 Photosynthesis practical?

  Position - Place the test tube rack with the boiling tube 10 cm away from the light source, measured using a ruler.
• What is the second step in the RP06 Photosynthesis practical?

  Prepare - Fill the boiling tube with a fixed volume of sodium hydrogen carbonate solution.
• What is the third step in the RP06 Photosynthesis practical?

  Insert - Place the cut pondweed into the boiling tube with the cut end at the top and gently push it down with a glass rod.
• What is the fourth step in the RP06 Photosynthesis practical?

  Equilibrate - Leave the boiling tube to rest for 5 minutes for the pondweed to acclimatize.
• What is the fifth step in the RP06 Photosynthesis practical?

  Start - Begin the stopwatch and count the number of bubbles produced in one minute.
• What is the sixth step in the RP06 Photosynthesis practical?

  Repeat - Repeat the bubble count two more times and take the mean for accuracy.
• What is the seventh step in the RP06 Photosynthesis practical?

  Record - Record the data in a table.
• What is the eighth step in the RP06 Photosynthesis practical?

  Distance - Repeat steps 1-7 for 3 more distances (20, 30, 40 cm) from the light source.
• What is the ninth step in the RP06 Photosynthesis practical?

  Graph - Plot a graph of the rate of photosynthesis (number of bubbles) against light intensity (using the inverse square law: light intensity = 1/distance²).
• What are the sources of error in the RP06 Photosynthesis practical?

  Temperature may affect the rate of photosynthesis. Bubbles may form too quickly to count.
• What are the potential hazards in the RP06 Photosynthesis practical?

  There is a potential allergy risk from the pondweed. The lamp may get hot. Be careful to keep water away from electrical outlets and wiring.