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Rate of photosynthesis.

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Rate of photosynthesis Results Distance (cm) Bubbles per minute Average Light intensity 1 2 3 0 240 249 251 246.7 5 201 222 214 212.3 11000 10 183 185 188 185.3 5800 15 154 152 158 154.7 3570 20 128 118 124 123.3 2320 25 93 88 90 90.3 1780 30 67 65 70 67.3 1320 35 53 50 4.8 50.3 1050 40 38 38 37 37.7 850 45 26 25 24 25 690 50 17 17 18 17.3 580 The temperature of the water stayed a constant of 20 degrees throughout the experiment. Analysis The graphs that I have drawn from my results confirm my prediction that as light intensity increases, so does the rate of photosynthesis. All of my results fall into this pattern. This is because the energy of the light is used to drive the reaction and obviously the closer the light is, the more energy given to the plant. ...read more.


However chlorophyll can only absorb so much light so after a while it has no effect. Evaluation Although I was happy with my results, looking back at my experiment there are a number of factors that could have made my results inaccurate or unreliable. The pondweed's rate of photosynthesis was not always at a steady rate. This was shown when I repeated each experiment three times and each time was slightly different. However I tried to overcome this problem by taking the average from the three results which meant that my results were more reliable. Another factor that could have effected my results was human error. This could have occurred from miscounting the number of bubbles. To improve the accuracy of my results I repeated each three times and found the average. ...read more.


Heat could have been added by using different temperatures of water. Since sodium hydrogen carbonate (NaHCO3) is used to provide the pondweed with carbon dioxide. Performing the experiment with different volumes of NaHCO3 could vary the amount of CO2. The plant would be kept at a constant distance from the lamp and a constant volume of water would be added to the sodium hydrogen carbonate. It could also be interesting to explore the effects of coloured lights on the rate of photosynthesis, which could lead to the question of whether or not other types of light, such as fluorescent lights or halogen lights, would have a different effect on the rate of photosynthesis. I think that overall the evidence is reliable and that the results show what I predicted. It could have been more accurate but I think it proves that as light intensity is increased photosynthesis speeds up. ...read more.

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