Light Intensity's Effect on Photosynthesis

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Light Intensity's Effect on Photosynthesis

Aim : To find out how light intensity will affect the rate of

photosynthesis in a piece of Canadian Pondweed.

Prediction : I predict that as I increase the distance between the

light source and the Canadian Pondweed (reducing the light intensity),

the volume of oxygen produced within the time limit (the measure of

the rate of photosynthesis) will decrease. This will happen because as

the light source is moved further away, less light rays will reach the

surface of the Pondweed, shown by this diagram;

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source

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Light rays Pondweed Light rays Light source

Pondweed

This will mean that less light (particles or waves) will go through

the clear Cuticle and upper Epidermis and reach the palisade layer.

This means that less light will reach each cell on average, and as

light is needed for photosynthesis to make the water and carbon

dioxide react together (making it a limiting factor) and so less light

means less water and carbon dioxide is reacted together in the time,

therefore there will be a decreased rate of photosynthesis, and less

oxygen produced will be produced as a by-product of the photosynthesis

reaction.

[IMAGE][IMAGE][IMAGE][IMAGE][IMAGE][IMAGE] I know that photosynthesis

will take place in the plant as there is all the factors needed for

photosynthesis available and present (water, carbon dioxide,

chlorophyll, and light) to the plant and therefore according to the

photos...

... middle of paper ...

...ble overall picture of

whether light intensity affects the rate of photosynthesis. I could

have extended the range on the distance axis so that I could find out

how this pattern evolves at the extremes of the axis and also do

sections of the range in more detail e.g. more dense results every 1mm

at the small end of the axis to see a more reliable pattern. I could

then conclude each part of the line of best fit in more detail and

explain the different stages of the experiment. I could have looked at

all the other limiting factors, maybe in the same experiment so I

could see the separate relationships and conclude which factor affects

photosynthesis more. Finally I could investigate the precise

mathematical relationship between these two factors using an equation

of the line of best fit and a Spearman's Rank calculation.

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