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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 * Set up apparatus like above with the light source 5 cm from the beaker and cut the end of the pondweed. ...read more.


2cm away from beaker at all times * Amount of KHCO3 added Why: The CO2 provided can affect the rate of photosynthesis How: One scapula full put in to the water with the pondweed every time * Dark room or same light around the pondweed other than the lamp Why: If more light is focused on the pondweed the rate of photosynthesis will be increased and it will not be a fair test. How: Investigation to take place in dark room Results: Test 1 Distance (cm) Bubbles 5 14 10 9 15 6 20 5 25 3 Test 2 Distance (cm) Bubbles 5 14 10 7 15 7 20 5 25 4 Distance (cm) Avg. Bubbles 5 14 10 8 15 6.5 20 5 25 3.5 Conclusion: The most bubbles were produced when the light intensity was 5cm away from the pondweed which means more oxygen is produced which suggests that the more light focused on the pondweed the more photosynthesis will occur and the photosynthesis occurred very fast on that measurement which also prooves my prediction was correct. ...read more.


The oxygen produced for both tests for the 20cm distance were the same which shows that the results were correct. The 25cm distance was also close and had an average of 3.5 bubbles per minutes which shows that all of my results were pretty much correct and less oxygen is produced when the light source goes further away. There were also no major anomilies but a couple of problems were faced during the investigation. The initianal pondweed used for some of the experiments did not produce any oxygen so the experiment had to be redun. To improvw this I should be using fresh autotrophic pondweed to produce oxygen first time around. Another problem faced was that the distance between the light and the beaker wasn't exactly spot on so to make this a better test the measurements should be taken accuretly and marks should be made where appuratus should be placed. ...read more.

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