Experimental Design on Plant Growth

What affect does fertilizer have on the rate of growth in plants over a certain period of time? When tested, there is no affect on the growth of plants from a change of an environmental factor, such as an exposure to fertilizer. By changing the independent variable (whether or not the plant was planted with fertilizer), you are testing to see how the dependent variable would change (the growth of plants). In order to assure that there is no experimental error, a control must be kept to produce the most accurate data on what effect fertilizer has on plant growth. Although many environmental factors could be tested, such as the amount of sunlight exposed to or the amount of water given, some of the controls in this experiment would be to keep both of the stated factors above the same, along with testing the same type and age of plant, testing in the same temperature, and planting in the same type of pot. In order to conduct this experiment, the only thing needing to be changed is having one plant growing with fertilizer in its soil, and one without. By doing so, we can see whether or not fertilizer has any effect on plant growth by measuring the mass of the plant (in grams) every 15 days. Two plants will be tested at the same time in order to keep all other environmental factors the same. Once finished, the data will be analyzed by graphing and charting the results to be able to compare the differences in growth. Once tested, the results show that on day 1, the plant not exposed to fertilizer began at 5 grams, and that the plant exposed to fertilizer began at 4 grams. After 15 days, the plant not exposed to fertilizer was measured at 12 grams, and the plant exposed to fertilizer was measured at 22 grams. Lastly, after 30 days, the plant not exposed to fertilizer was measured at 21 grams, and the plant exposed to fertilizer was measured at 48 grams. In conclusion, the original hypothesis that environmental factors had no effect on plant growth was proven faulty