Essay On The Effect Of Light Intensity On Leaf Discs

Superior Essays
Register to read the introduction… iii) Light intensity, cm-2
Formula of light intensity = (1/distance2) = cm-2
Eg : for 10cm = 1/((10.00cm)²) = 1/(100 cm²) =0.0100 cm-2
Distance of leaf discs from the light source (±0.05) cm Light intensity (cm-2)
10.00 0.0100
15.00 0.0044
20.00 0.0025
25.00 0.0016
30.00 0.0011
35.00 0.0008
Table 6: The table shows the light intensity (cm-2) of leaf discs for each distance (±0.05 cm) iv) Uncertainty of light intensity (cm-2) for leaf discs.
Formula : Δ L = [(Δ d/d) + (Δ d/d)] × L
Keys:

ΔL =Uncertainty light intensity
L =Light intensity
Δd =Uncertainty of distance d =Distance

Eg : for 10cm = [(0.05/10.00) + (0.05/10.00)]cm × 0.0100 cm-2 = ± 0.0001 cm-2
Distance of leaf discs from the light source (±0.05) cm Light intensity (cm-2)with uncertainty
10.00 0.0100 ± 1.000 x 10⁻⁴
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Conclusion :
The purpose of this experiment is to measure the effect of light intensity on the rate of photosynthesis in leaf discs. In this experiment, leaf disc is used and the CO2 gas inside the leaf discs are expelled in the beginning of experiment. Then, leaf discs are immersed in 3% Sodium Hydrogen Carbonate Solution. To indicate that the photosynthesis has occured is when the leaf discs rise on the surface of solution. This means they had absorbed CO2 from Sodium Hydrogen and received light form the lamp.
By using different distace between the lamp and the surface of table which are (10, 15, 20, 25, 30 and 35) cm. The distance will be measures as light intensity by using the formula (light intensity/average time) cm-2 s-1. The concept of this experiment is, CO2 is needed to be absorbed by the discs leaf in order for phothosynthesis to occurwhich the products will be glucose and oxygen.Thats why we use 3% Sodium Hydrogen Carbonate Solution in the beaker since it can provide CO2. Since the factor of light intensity is being tested, other factors such as temperature and concentration must be
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In this experiment, the shorter the distance between the leaf discs and the light source, the higher the light intensity, thus the higher the rate of photosynthesis in the leaf discs.The theory of Photosynthesis is that it can occur in high or low light intensity. At low light intensity, where the distance is far, there will be a shortage of the product of light independent reactions. The products which decreased are NADPH2 and ATP energy. As the distance becomes shorter, meaning the light intensity increases , more products will be produced. It will later be used for light independent reaction which increases its products. That is why the rate of photosynthesis increases. But, the rate of photosynthesis at some point will have no further increase even if light hypothesis is

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