Surface Area of Leaves

Surface Area of Leaves
Aim: To find a connection between the size(surface area) of the leaf and the distance between the trunk and the road. Hypothesis: Yes, I believe that the surface area of the leaves will increase the further away from the road they are. I believe that there are many reasons all due to different pollutions, caused by the cars driving on the road. I?m sure that it affects the leaves in other ways such as premature leaf drop, delayed maturity, plant growth, reproductionâ??.but also the size will get affected. Cars are responsible for a tremendous amount of air pollution and wasted energy that affect humans and our environment. Acid rain, which is caused by air pollution, poisons our water as well as plants.
The smoke and fumes from burning fossil fuels rise into the atmosphere and combine with the moisture in the air to form acids rain. The main chemicals here are sulphur dioxide and nitrogen oxides. The tree?s roots absorb water from the ground, as a life source and when the acid rain, rains around that tree its life source is poisoned. The acid rain also harm the leaves as fog, acid fog, which the leaves will bath in, and that will make their protective waxy coating can, wear away. Which could lead to water loss, which makes the leave decrease in surface area. I also think that since the acid reacts with nutrients that the tree needs, such as calcium, magnesium and potassium, it?ll starve the tree, which will affect the individual leaves. And when the leaves are damaged they can?t produce enough food energy (by photosynthesis) for them self and the tree to remain healthy. Except for the acid rain I believe that ethylene harms the leaves. Ethylene is one of the many products of car, truck and bus exhaust and it also results from the incomplete combustion of coal, gas and oil for heating. As known ethylene modifies the activities of plant hormones and growth regulators, and amongst other things it causes stunt of growth. Method: We went to ?Kungsparken? just outside our school to investigate some leaves. We decided to pick leaves from trees further and further away from the road (Regements gatan). Which made my independent variable, the distance to the street, and the dependent variable, the surface area of the leaves that were picked. All the leaves were picked from the same species, the beech. We picked the leaves randomly but from the same height. Which were my controlled variables. To measure the distance steps that were measured as approximately 1 metre were used. From every beech four leaves were picked. These were put on a millimetre paper and drawn, which allowed us to calculate the surface area, by counting the squares on the paper. The results from the leaves that came from the same tree were added and divided by four, which gave us the average area for the leaves coming from the same tree. These results were then plotted on a graph. Data collection: Tree no. Distance from street (stepsâ?ˆ1m)Â?0,5m Surface area of 1:st leaf (cm²) Surface area of 2:nd leaf (cm²) Surface area of 3:rd leaf (cm²) Surface area of 4:th leaf (cm²) Mean surface area (cm²) 1 2,43 36,5 25,8 28 34,5 31,2 2 29,5 30,5 13,5 17,5 32 23,375 3 45,5 42,5 24 43â?? 32â?? 35,625 4 55 29,8 34 22,5 26 28,075 The table gives us the different areas that were calculated, and also the average area of the leaves that came from the same tree which we got from adding the four results and dividing the answer given by four. Data processing: See graph. Evaluation (Conclusion and errors):From the results I got I can draw the conclusion that, No there is none connection between the surface area of the leaf and its distance to the street. From my results I could see that the average surface area for the leaf didn?t increase the further away from the street it was situated. In fact there wasn?t any special pattern in how the area increased/decreased. So back to my hypothesis, I was wrong. It didn?t have to do with pollution, at least not that much so it would make any difference in my results. So my conclusion now is that what affects the size could be how much sunlight it has ?received?, the age of the tree and the leaf, the soil moisture, nutrient supply and time of year. And leaves developing in nearly full shade often differ dramatically (in appearance) from leaves at the ends of branches in full sun near the top of the tree. Factors that have made our investigation less accurate (errors) are the fact that we didn?t know the age of the tree, or the age of the leaves. We also didn?t know if the tree was injured or sick, which might have affected the result we got. Another error could be the trees genetics, perhaps all the leaves on the trees we chose were small due to genes. And whether or not the tree was in the shadows or under the sun. Whether or not the pollution has an affect on the size of the leaves, I know that it does effect our environment and air quality continues to be a major concern all over the world.

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