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Biology - How Light Intensity Affects the Rate of Photosynthesis

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Biology - How Light Intensity Affects the Rate of Photosynthesis

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  • July 10, 2005
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Biology Coursework ¡V Does The Light Intensity
Affect the Rate of Photosynthesis

The Investigation

In this experiment I will investigate the affect in which the light intensity will have on a plants photosynthesis process. This will be done by measuring the bubbles of oxygen and having a bulb for the light intensity variable.


The input variable which will be used in this investigation will be the light intensity (this will be a 100Watt bulb being moved closer and further away from the plant). The outcome variable which will change as a result of this experiment will be the amount of oxygen made in the experiment due to the amount of light intensity increases (causing the plant to photosynthesise more).


I predict that as the input variable, the light intensity increases (the light moved towards the plant) the outcome variable, the amount of oxygen, produced from photosynthesis will be larger. Plants can absorb and use light energy because they have a green pigment, chlorophyll, contained in the chloroplasts in some of their cells. Chlorophyll allows the energy in sunlight to drive chemical reactions. Chloroplasts act as a energy transducers, converting light energy into chemical energy. So as the plant has more light the chlorophyll inside the chloroplasts can react faster absorbing in more light for food and energy. The equation for photosynthesis can help to predict the outcome of the investigation.
Light Energy
Carbon Dioxide + Water --------------„³ Glucose + Oxygen

This shows that there could be three variables in this experiment, carbon dioxide, water and light energy. So in our case the variable light energy (light intensity) will be used. The equation also shows that if there is more light energy then more glucose and oxygen will be produced. I also predict that as...