Experiment to show the rate of photosynthesis

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Experiment to show the rate of photosynthesis

Aim: Experiment to show the rate of photosynthesis when pondweed is under different life intensities.

Prediction: I predict that the closer the light is to the pondweed the (or the higher the light intensity) the more oxygen will be produced until a certain point where the temperature or carbon dioxide levels will be the limiting factor. The further away the light, the slower the oxygen bubbles will be produced so the less light the less photosynthesis will occur which is needed for the plant to make food.

        
                                             The rate increases (A) but     only to a certain extent. Then they don't increase any more because of the other limiting factors of the carbon dioxide levels and temperature.

Method:

  • Lamp
  • Sodium Hydrogen Carbonate
  • 1 Meter Ruler
  • Water
  • Beaker
  • Stopwatch
  • Pondweed
  • Measuring Cylinder
  • Scales
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  • Set up apparatus like above with the light source 5 cm from the beaker and cut the end of the pondweed.
  • Some potassium hydrogen carbonate might have to be added which provides carbon dioxide for the plant which is needed for photosynthesis. Then wait for the plant to 'acclimatise'.
  • Count the number of bubbles seen in 1 minute which is a way of measuring the rate of photosynthesis.
  • A row of dots on paper while counting can represent each bubble counted.
  • Move the light 10cm away. Wait 2 minutes and then count the bubbles again.
  • Repeat this ...

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