Lab report
Aim: to be able to find out the effect of light intensity on the rate of photosynthesis
Hypothesis: I think that as the light intensity will increase or the light source will get closer, the plant will produce more oxygen meaning more bubbles will be produced. Therefore the photosynthesis will become quicker
Materials: power pack, elodea plant, lamp, test tube, room temperature water, thermometer, ruler, stopwatch
Variables
Independent-changing light intensity or the distance of the light source from the plant
Dependent- bubbles produced per minute
Variable-
Method * Step 1 place the Elodea pondweed in a testube filled with room temperature water. * Step 2- place the testube with the elodea pondweed into another beaker filled with room temperature water. Use the thermometer to check the temperature of the water. * Step 3 – connect the lamp to a power pack and keep it at the same voltage or power. * Step 4- place the beaker with the testube in front of the light source ( lamp) * Step 5 – use a ruler to measure the distance between the lamp and the beaker each time doing the experiment. * Step 6 – Count the bubbles per minute made by the elodea plant using a stop watch and record the results in a table format. * Step 7 – to ensure accuracy repeat the experiment several times using different distances (at least three times) and replace the water in the beaker each time after the experiment.
Source: virtual experiment done from the following website http://www.reading.ac.uk/virtualexperiments/ves/preloader-photosynthesis-full.html Data and results: Distance | 140 mm | 150mm | 160 mm | Number of bubbles produced | 87 bubbles per minute | 64 bubbles per minute | 45 bubbles per minute |

Conclusion – from the data collected above we can come to the conclusion that the higher the light intensity the faster photosynthesis will take place. This was proved as there were more bubbles produced per minute when the light source was kept closer i.e.: higher light intensity speeds up photosynthesis and affects the rate of photosynthesis.
Evaluation: If I were to do this experiment again, instead of doing it virtually I would do it in real and repeat the experiment at least three times with each distance to ensure accuracy. Furthermore I believe the results of this experiment are not very accurate and only an estimation since the bubbles were counted by a human eye and we can often make mistakes by missing a bubble or two.