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How light affects the rate of photosynthesis

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How light affects the rate of photosynthesis Aim To see how light affects the rate of photosynthesis Introduction Photosynthesis occurs only when light is present, and takes place in the chloroplasts of green plant cells. The definition of photosynthesis is the production of simple sugars from carbon dioxide and water causing the release of sugar and oxygen. The chemical equation for photosynthesis can be expressed like this: (Light) 6CO2 + 6H2O C6H12O6 + 6O2 (In the presence of chlorophyll) Also the word equation can be expressed like this: Light CO2 + H2O Glucose + O2 Chlorophyll Plants need light to photosynthesis, and so that without light, the plant would die. The reason that light intensity does affect the rate of photosynthesis is because the light energy is absorbed by the chloroplasts and then the chlorophyll makes then energy for the plant to use. There for if the more light taken by the chloroplasts (to a certain limit depending on the plant) ...read more.


1 x measuring flask (filled with tap water) 1 x piece of pondweed (eklodea) 1 x stopwatch 1 x pen and paper (to record results) The method I use is as follows: 1. Pour water into the flask to about 3/4 of the total. 2. Place the light source 50cm away from the pond weed. 3. Measure this accurately by using the 100cm ruler. 4. Start the stop watch as you turn the light source on. 5. Count the amount of oxygen bubbles being released from the pond weed during the time period of 1 minute and record your results. 6. Move the light source 10 cm closer 7. Begin counting the amount of bubbles again through a time span of 1 minute and record your results 8. Move the light source 10 cm closer Begin counting the amount of bubbles again through a time span of 1 minute and record your results 9. ...read more.


Ways of improving this experiment are limited I could have made more results by moving the light source 5cm closer each minute of prolonging the minute to 2 minutes to get more precise and accurate readings. Another factor that may have caused inaccurate readings was the light already coming in through the classroom windows I suggest next time placing blinds over the windows preventing any foreign light affecting the experiment. I do believe this test was fair as the only factor I changed was the range of the light source. I kept the light source the same, the pond weed the same, the water the same and the ruler the same. From this investigation I have learnt that plants are more complex then I first imagined, before this investigation I never took into consideration the plants we see all around us each day where making their own food constantly from now on I will see plants in an entirely different prospect. Joseph Maher ...read more.

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