The Effect of Wavelength on Photosynthesis Rate

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The Effect of Wavelength on Photosynthesis Rate

Aim:

To investigate how different wavelength (colors) of light affect the

photosynthetic rate. I will use a pant that is a pond weed called

elodea. I will measure the rate of photosynthesis by measuring the

amount of o2 given off in bubbles per minuet from the elodea. I will

do this by placing the Elodea in a test tube with sodium hydrogen

carbonate then I will vary the light wavelength (color) using colored

filters and count the number of oxygen bubbles given off using a

pencil dot technique.

Prediction

I predict that with a blue filter the photosynthetic rate will be the

highest as blue is a highly absorbent color it also has a short

wavelength so carries the most energy. The color to have the least

photosynthetic rate will be green as although it has quiet a short

wavelength so a lot of energy it will be reflected by the plant and

not absorbed. Yellow and orange will have average photosynthetic rates

although orange will be slightly more as it is more absorbent than

yellow even low it has a longer wavelength and dose not carry as much

energy as yellow would. Red will have a very high photosynthetic rate

as even though it has the longest wavelength and therefore carries the

least energy it will be greatly absorbed so a lot of the light energy

will be used rater than reflected.

Prediction graph.

[IMAGE]

Photosynthetic equation

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[IMAGE][IMAGE]6CO2 + 6h20 light energy and chlorophyll C6H1206 + 6O2

Carbon dioxide + water converted into glucose and oxygen

Theory of photosynthesis

Photosynthesis is a chemical reaction, which uses the energy from

sunlight to convert carbon dioxide and water to oxygen (The bi

product) and glucose. Plants trap the energy in sunlight using

chlorophyll a light trapping pigment found in leaf plant cells. It

then uses carbon dioxide which enters the plant by small holes found

on the underside of the leaf called stoma and water which enters the

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