Photosynthesis

• What is the formula equation for photosynthesis?

  Carbon dioxide + water → glucose + oxygen
• What do green plants use to produce glucose and oxygen?

  Carbon dioxide and water in light energy
• What factors can affect the rate of photosynthesis in the practical?

  • Light intensity
  • Carbon dioxide concentration
  • Temperature
• What type of plant is used in the photosynthesis practical?

  Aquatic plant, specifically pond weed
• Why is sodium hydrogen carbonate solution added to the boiling tube?

  To encourage the pond weeds to photosynthesize
• How is the pond weed prepared for the experiment?

  Cut and placed in sodium hydrogen carbonate solution
• What is the purpose of cutting the stem of the pond weed underwater?

  To observe the oxygen bubbles produced
• How is the rate of photosynthesis measured in this experiment?

  By counting the number of oxygen bubbles produced
• What angle should the pond weed be cut at for optimal oxygen production?

  At an angle across the stem
• What is the independent variable in this photosynthesis experiment?

  Light intensity
• How can light intensity be changed in the experiment?

  By changing the distance from the light source
• What type of light source is suggested for the experiment?

  LED light source
• Why is it important to keep the temperature constant during the experiment?

  To ensure a fair test without additional variables
• What should be done before taking measurements of oxygen bubbles?

  Allow the pond weed to adjust to light
• How many bubbles were counted at a distance of 10 cm from the light source?

  23 bubbles
• What distances should be tested for the independent variable?

  10, 20, 30, 40, and 50 cm
• What is an alternative method to measure oxygen production in the experiment?

  • Collect gas in a boiling tube
  • Use a glass funnel to trap oxygen
  • Measure the volume of oxygen produced
  • Test with a glowing splint to confirm oxygen
• What happens to the water in the boiling tube during gas collection?

  It is displaced by the produced oxygen
• What indicates that oxygen is being produced by the pond weed?

  Bubbles of gas escaping from the stem
• What is the importance of light energy in photosynthesis?

  It is necessary for glucose and oxygen production
• What role does chlorophyll play in photosynthesis?

  It captures light energy for the process
• Why is controlling carbon dioxide concentration important in photosynthesis experiments?

  To ensure accurate measurement of photosynthesis rate
• What is the significance of fair testing in scientific experiments?

  To ensure reliable and valid results
• How is a timer used in measuring the rate of photosynthesis?

  To count bubbles produced in one minute
• What tool is used to cut the pond weed?

  Dissecting scissors
• Why is it important to align the boiling tube with the light source?

  To ensure consistent light exposure for the plant
• What is the procedure for testing the gas collected with a glowing splint?

  It should relight to confirm oxygen presence