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Photosynthesis.For my experiment I have chosen to use light distance as my variable.This means that to carry out a fair test everything else must be kept the same

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Introduction

Photosynthesis Photosynthesisto find effects of distance of a light source from pond weed has on the amount of oxygen produced Photosynthesis All green plants need to be able to make their own food.They do this by a process called photosynthesis.For photosynthesis to occur they need sunlight energy.This energy is absorbed by a green pigment called chlorophyll,which is mainly found in the leaves.This energy then combinEs with water molecules (from the soil) and carbon dioxide (from the air).Then as a result of this,a type of sugar is produced .This is called glucose.Also oxygen is made. For my experiment I have chosen to use light distance as my variable.This means that to carry out a fair test everything else must be kept the same during the experiment. Hypothesis I think that as the light source (desk lamp) is moved closer to the pondweed,the rate that oxygen is produced will increase therefore more oxygen willbe produced and also more glucose. I believe this will happen because when the the light source is nearer to the plant more of the plants surface area is coming ...read more.

Middle

� Take results after three minutes for each induvidual experiment. Safety � Follow lab safety rules (eg no running bags at back etc). � keep the desklamp away from contact with water. � Be careful when using scapuar. Method � Collect apparatus. � Set up apParatus as in diagram. � Fill measuring cylinder and beaker with water. � Add carbon dioxide mixture to water. � Set up desklamp in correct position(eg 10cm). � Turn on desklamp and start stopwatch. � Count the bubbles for the next three minutes and also make a note of the change in volume. � Record your results. � Repeat experiment twice more for distance 10cm and then do the same with distance 20,30,40,50,60,70,80,90, and 100cm. Results These are my results Because my results did not go entirely to plan(because my pondweed was not photosynthesising quick enough) I have been given a past years results which I will now usS as my results instead.They are as follows- Analysis Looking at my results a can see a significant increase in the rate of photosynthesis as the distanse decreases.All of ...read more.

Conclusion

Evaluation I think that on the whole my experiment was ok.The results i gathered were very odd i belive this is because of the poor quality of the pondwed we used.But with the set of resuts we were given we were able to calculate acurate averages which followed my prediction. I belive our measurments were about as accurate as we could get usill oung the apparatus that we did. We experienced quite a few problems throughout our experiment.These were first of all in our first experiment our pondweed was not of a high standard and was photosynthesizing very slowly the only way we could have got around this problem without using new pondweed would be to leave the experiment for longer.Another problem we encountered was the change in temperature when the desklamp was close to the pondweed because we could not do anything to ammend this we had to accept any slight change in our results.another problem we faced was counting the bubbles when the plant was photosythesising the bubbles were different sizes,but as talked about in my pelimenary data we overcame this problem by counting every individual bubble as one. ...read more.

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