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Experiment to find out whether or not the intensity of light affects the rate of photosynthesis

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Introduction

Experiment to find out whether or not the intensity of light affects the rate of photosynthesis Photosynthesis What is photosynthesis? Photosynthesis is the process that plants use to produce food. What does a plant need to perform the process of photosynthesis? A plant will need: Light, as the energy source that can make photosynthesis happen, Carbon Dioxide, and Water. Also the plant will need suitable conditions, for example, the optimum temperature and pH value of the soil. The plant will also need Chlorophyll (a green pigment), but the plant creates this itself and the substance is already present in the plants' chloroplasts. What does the process of photosynthesis make? Photosynthesis makes 2 substances: Glucose and Oxygen. Glucose is used by the plant to make the basis of many other molecules. Oxygen is considered a waste product of the plant, however, plants need oxygen to respire, so, during the night, when there is not an adequate amount of light to photosynthesise reasonably, the plant will be respiring using the oxygen to create food and energy. Where does the process of photosynthesis take place? Photosynthesis takes place in the chloroplasts of the plant, which are mainly in the palisade cells of the leaves. ...read more.

Middle

Weight some Cabumba with a paperclip and place it in the beaker, so that the Cabumba doesn't float on the surface of the water which would make counting bubbles difficult, 3. Place the lamp 10cm from the beaker, 4. Start the stop-watch and count how many bubbles of oxygen are produced in 1 minute, 5. Move the beaker 10cm further away from the lamp and repeat the experiment, repeat the experiment in order to make certain that there are no anomalous results, 6. Repeat steps 4 and 5 until you are satisfied with the amount of results that you have, 7. Repeat the whole experiment again from step 1. The experiment would not be fair because there is other light in the room which could affect the rate at which photosynthesis occurs, such as the fluorescent striplights on the ceiling and the light coming in through the windows. I think that I could have made the experiment fairer by blacking out the room completely and making sure that the only light in the room was the lamp which I was using. The independent variable in this experiment is the intensity of (or distance from) ...read more.

Conclusion

My results in the second run of the experiment could not have been accurate and reliable because the apparatus were set up next to a window, as I explained on page 5. I realised this and repeated the experiment in a blacked out room. To support my results, I investigated the intensity of the light (measured in Lux) at the different measurements to see if it was proportional to my results, over the page is my results table and graph. As you can see from the graph, the light intensity reduces as the light is moved further away from the Cabumba, and so does the number of bubbles per minute. To investigate this further, it would be possible to collect the amount of oxygen in a container as the plant produced it and measure it with some sort of device. Overall though, I have found out that, the further away Cabumba is from a light source, the less it produces oxygen. This is because it needs the light as an energy source for the process of photosynthesis (see top of page 2), however the number of bubbles will only increase as long as there is enough Carbon Dioxide and water available to the Cabumba, and the Cabumba is not dead. ?? ?? ?? ?? Andew Todd - 10ND - Biology Coursework Assignment ...read more.

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