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The aim of this investigation is to find out whether the change in light intensity affects the rate of photosynthesis in pondweed

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Science Coursework, Photosynthesis The aim of this investigation is to find out whether the change in light intensity affects the rate of photosynthesis in pondweed. I predict that as the light intensity increases by the lamp getting closer to the pondweed then the temperature and the rate of oxygen bubbles and the rate of photosynthesis will increase. Photosynthesis can be explained by using the word and symbol equations which are: Carbon Dioxide + Water + Light Energy Glucose + Oxygen + Water. The balanced symbol equation is: 6CO + 12H O C H O + 6O + 6H O. And what happens in these equations is that the water is absorbed through the many root hairs and is used along with the absorption of carbon dioxide in the air all can be used to convert into glucose and oxygen is released into the air to be used by us and other land animals that need it. During photosynthesis green plants transform light energy to chemical energy and use that energy to synthesize organic fuel molecules that can be stored in the form of carbohydrates. Carbon dioxide from the atmosphere provides the carbon source for photosynthesis and water provides the hydrogen needed to reduce the carbon dioxide in the formation of carbohydrate molecules. The way that all the minerals and water etc get around the plant is through the vascular bundles all over the plant which are made ...read more.


* We then turned on the lamp and started the stopwatch and waited 2 minutes for the process of photosynthesis to begin. * We then stopped the stopwatch and started to count the amount of oxygen bubbles that rose to the top of the test tube. * We then repeated this process again at the measurement of 35cm then 30cm and so on until we got to 5cm and then stopped and repeated the whole thing twice more so that we could have a range of results. Diagram Distance (cm) No. of oxygen bubbles 1st try No. of oxygen bubbles 2nd try No. of oxygen bubbles 3rd try Average 40 43 34 41 39.333 35 41 43 40 41.333 30 38 58 39 45 25 37 50 41 42.667 20 43 52 43 46 15 42 51 51 48 10 44 53 55 50.667 5 46 50 50 48.667 Analysis Looking back at the results shows that there isn't really a pattern in them because they are all going up and then down or down and the up and its al changing. But if we take out a few results then we can try and realise from my prediction that the rate of photosynthesis is increasing while the light intensity increases. If the light intensity doubles the rate of photosynthesis does not usually double it increases but does not double. ...read more.


1.8 1.7333 20 2.2 2.2 2.2 2.2 15 2.5 2.5 2.5 2.4333 10 2.5 2.5 2.5 2.4 5 2.4 2.4 2.4 2.3 Conclusion Looking at my results I can see that as the light intensity increases the rate of photosynthesis also increases this proves that my prediction was true. Evaluation My investigation went well because looking back at my results it shows that my prediction was true and this means that my investigation was done correctly as well. The reason it went well is because I was able to repeat the experiment and I was given the chance to do a preliminary coursework or a first draft to improve on. There was a couple of anomalous results which were not fitting with the pattern and looked out of place and this could be due to anything not being exact in the experiment. The reason could be to do with outside light not being completely blacked out the inside lights not being turned off or it could be the fact that we continued the experiment on for two days. To improve this we could black out the windows and turn off the inside lights we could have used the same plant over the two days or could have done the experiment in one day. The ICT experiment gave out no anomalous results and was a complete success and was completely accurate so it was better than the normal experiment. ...read more.

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