My aim in this experiment is to find out if the amount of light given to a plant affects the amount of oxygen given of in the process of photosynthesis.

Light and chlorophyll

Carbon dioxide + Water Sugar + Oxygen

I no this because of experiments I have already done testing the rate of photosynthesis:

Is light essential for photosynthesis? Leaving 1 plalnt in the dark and 1 in light. I then measured oxygen given of in both. The one in the dark didn't create any oxygen the one in light produced oxygen.

I will now go on and use a computer simulation to test how light intensity effects photosynthesis. I will record results at 10 different light intensitys: 10,20,30,40,50,60,70,80,90,100 all these are measured in arbitry units. If I was doing the experiment I would do it each measurement 3 times and take an average but since it is a computer simulation the results will be the same.

Fair Test

The variable in this experiment is light intensity. I predict that this controlling factor of photosynthesis will increase the oxygen produced as the arbitrary units are increased. The controlling factors I will keep the same are temperature at 25°C and the amount of NaHC03 at 5%. It is important I keep theses two controlling factors the same to ensure a fair test.

Temperature- It is important I keep temperature the same because it is a controlling factor in this experiment. If I increase the temperature the enzyme in the leaf will work faster producing more oxygen. If the temperature is increased over 45°C the enzymes will denature.

NaHCO3- it is important I keep this the same to ensure that the plant has the same amount of carbon dioxide to take in. If not it will not be a fair test.

Safety

There are no risks in this experiment because it is a computer simulation.

Apparatus

The apparatus I use in this experiment are: Gas syringe,

Capillary tube,

Elodea (plant),

Lamp,

Stop watch.

Method

I moved the lamp closer to Elodea to increase the light intensity and collect the amount of oxygen collected in the gas syringe. I will do this at 10 different light intensities 10,20,30,40,50,60,70,80,90,100 all these are measured in arbitry units. I will Record these results in a table and draw a graph of them.

Results

Light intensity (arbitrary units)

Oxygen collected

0

5

20

0

30

5

40

20

50

25

60

30

70

35

80

40

90

45

00

50

Conclusion

I can conclude after analysing and drawing a graph of my results that the rate of photosynthesis increased as the light intensity increased. I can say this because the Gradient of the graph is 0.5 so therefore for an increase of 1 arbitrary unit there is an increase of 0.5 mm oxygen collected. The rate of photosynthesis increased as light intensity increased because of more light being captured in the leaves. This will no doubt result in more head on collisions with the chloroplast in the leaf. My prediction was correct in a way but the graph did not ploto out because of the high level of NaHCO3 around the plant providing enough carbon dioxide for the elodea to react with no matter how strong the light intensity. The prediction did say that the rate of photosynthesis was going to increase in when so light intensity is increased so it was right in a way.

Evaluation

The procedure to obtain results was perfect because it was a computer simulation. If I was to do the experiment I would have recorded each result 3 times and taken an average but because it was a computer simulation it would have been pointless because all the results would have been the same. The results drew a perfect straight-line graph with no anomalous results. The results were good enough to write a conclusion. I expect that the reliability of the results to be reliable because it was a computer simulation and shouldn't be wrong. Further work I would do on this experiment would be to do the exact same experiment again using a less concentration of carbon dioxide so I could see a what point the plant ran out of carbon dioxide and the graph ploto out. I will also do the experiment changing the temperature. I would expect the enzyme to denature and photosynthesis to stop at the temperature 45°C. I would expect the amount of oxygen to increase as the temperature increases. This is because as higher temperatures the enzyme would have more energy and speed up the reaction. Up to the temperature of 45°C.