pond weed photo syntheseis
... Fair Test To ensure that a fair test is carried out the following things must be done. The same pondweed must be used every time we change the light distance, as the only variable in this experiment is the distance of the desk lamp. Do the experiment three times for each distance to get an accurate averages the equipment we are using is not very accurate There must only be one variable and that is the distance of the light source from the plant. Take results after three minutes for each individual experiment. Safety * Follow lab safety rules (e.g. no running bags at back etc). * Keep the desk lamp away from contact with potassium hydro carbonate * Wear goggles. Method * Collect apparatus. * Set up apparatus as in diagram. (See appendix 1). · * Fill measuring cylinder and beaker with potassium hydro carbonate· * Set up desk lamp in correct position 60cm * Turn on desk lamp and start stopwatch. * Count the bubbles for the next three minutes. * Record your results. * Repeat experiment twice more for distance 60cm * Do the same for every other distance Results These are my results (see appendix 2) Analysis Looking at my results a can see a significant increase in the rate of photosynthesis as the distance decreases. All of the results I was given show this pattern. In the experiment when the distance was 60cm there was not much photosynthesis taken place only about 1-2 bubbles of oxygen were produced, but when the desk lamp was 10cm away a lot of photosynthesis was occurring on average 26.75 bubbles in three minutes a quite substantial difference from 60cm;overall it was quite a significant increase. I believe this is because when the desk lamp is close more of the pondweeds surface area has light energy shining upon it, which means more photosynthesis will occur in a shorter time. The average no. of bubbles for different distances are as follows (see appendix 3) Looking at my results it is quite evident that the number of bubbles produced is much greater when the distance of the pondweed from the desk lamp is less. This proves that my original hypothesis was correct that "as the distance decreases of the desk lamp from the pondweed therefore more oxygen bubbles are produced". As I mentioned before this is because there is more light energy shining on a greater surface area when the desk lamp is closer so therefore greater surface area equals more photosynthesis. Evaluation I think that on the whole my experiment was ok. The results I gathered were very odd I believe this is because of the poor quality of the pondweed we used also people in the lab walked in front of the lamp a few times. But with the set of results we were given we wer...