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Introduction

1.0 Abstract The purpose of this investigation was to determine what effects different pH levels, more specifically pH 3, 5, 7 and 9 have on the rate of growth of plants. It was hypothesised that if the pH is neutral, the growth of the plant will increase because the maximum availability of primary nutrients required for plant growth is greatest at a pH value between 7 and 9. Consequently if the pH is acidic then the growth of the plant will decrease because availability of primary nutrients required for plant growth will be less at a pH value between 1 and 4. An experiment was designed to determine what pH had the most positive effect on the rate of plant growth. It was found that pH 7 caused the largest rate of growth for the plants, with pH 9 following closely behind. Therefore the optimum pH for plants was in fact a pH of 7-9, however, in particular 7. 2.0 Aim To investigate the effect of varying levels of pH on the growth of broad bean plants, thus determining the differences in growth between broad bean plants with higher pH levels and lower pH levels. 3.0 Hypothesis If the pH is neutral, the growth of the plant will increase because the maximum availability of primary nutrients required for plant growth is greatest at a pH value between 7 and 9. If the pH is acidic then the growth of the plant will decrease because availability of primary nutrients required for plant growth will be less at a pH value between 1 and 6. If the pH is altered then the rate of photosynthesis will also alter. If the optimum pH for photosynthesis is not met, then the plant will not obtain sufficient food or nutrients, thus the plant will not grow sufficiently. 4.0 Introduction This investigation focuses on the effects that different pH levels may cause on the rate of growth of plants. ...read more.

Middle

59.96 41.07 42.46 51.77 61.89 55.54 38.58 41.67 45.49 53.78 58.24 39.83 44.87 42..42 55.44 58.84 30.45 37.09 Height (cm) 3.6 2.2 2.5 3.3 2.5 3.9 4.3 3.3 8.3 7.1 13.1 8.1 6.3 6.8 7.2 9.1 3.0 5.3 Leaf Number Count 2 2 2 2 2 2 2 2 2 3 4 4 3 3 2 2 1 1 Distance Between Nodes Stem Height Compared to Actual Height Table 4: Day 8 Data Collection Data Table 5: 26-7-11 Plant Number 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 pH Tested 3 5 7 9 Tap Water Weight (g) 54.69 37.88 37.91 46.08 57.90 53.18 34.67 38.46 41.27 49.62 54.67 35.35 41.14 39.95 51.07 53.43 28.56 35.10 Height (cm) 4.1 2.8 3.0 3.8 3.0 4.4 4.8 3.9 8.9 7.8 13.7 8.7 6.8 7.3 7.8 9.6 3.5 5.7 Leaf Number Count 2 2 2 2 2 2 2 2 2 3 4 4 3 3 2 2 5.5 0 Distance Between Nodes - 0 - - - - 12.0/3.0 0 - - 13.0/1.0 - - - 5.0/3.0 Stem Height Compared to Actual Height 3.5 3 3.5 5 Table 5: Day 12 Data Collection Data Table 6: 29-7-11 Plant Number 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 pH Tested 3 5 7 9 Tap Water Weight (g) 58.73 43.48 42.45 50.91 61.77 59.76 39.80 44.37 45.66 53.22 58.14 39.32 46.16 46.55 55.29 57.06 43.95 48.63 Height (cm) 4.4 3.0 3.2 4.0 3.2 4.7 5.1 4.2 9.2 8.1 14.0 9.0 7.0 7.6 8.1 9.8 4.0 6.0 Leaf Number Count 2 2 2 2 2 2 2 2 2 3 4 4 3 3 2 2 1 1 Distance Between Nodes - 0 - - - - 12.0/3.0 0 - - 13.0/1.0 - - - 5.0/3.0 Stem Height Compared to Actual Height 3.5 3 3.5 5 Table 6: Day 15 Data Collection Data Table 7: 1-8-11 Plant Number ...read more.

Conclusion

A more accurate measuring system would be needed in future in order to achieve more precise results. The data gathered from this experiment is very relevant as the results obtained show the degree of usefulness of pH for maximum plant growth. For gardeners and farmers when growing plants and produce it is important to know what level of pH will enable them to have maximum plant growth. This experiment is extremely relevant as it shows that pH 7-9 results in larger and steadier plant growth. As these results show a very substantial difference in the growth rate of plants watered with pH 3 and 5 and pH 7 and 9 in such a short period of time, this experiment could benefit gardeners and farmers immensely as they have the knowledge to maximise their plant growth. It is therefore an extremely relevant experiment and should be repeated over a longer period of time to obtain more accurate results. After acquiring information from this investigation, it is possible for further investigations to be conducted continuing on from the above findings. Firstly, an investigation into the use of different amounts of pH 7 to determine if pH 7 could have a negative effect on plant growth if received in small or large amounts. Secondly, investigate how 9.0 Conclusion In conclusion, in completing this experiment it was found that the results did in fact support the formulated hypotheses. Firstly, that if the pH is neutral, the growth of the plant will increase because the maximum availability of primary nutrients required for plant growth is greatest at a pH value between 7 and 9. Secondly, if the pH is acidic (pH 1-6) then the growth of the plant will decrease because of availability of primary nutrients required for plant growth will be less. Lastly, if the pH is altered then the rate of photosynthesis will also alter. If the optimum pH is not met, then the plant will obtain sufficient food or nutrients, thus the plant will not grow sufficiently. Therefore the experiment was successful in supporting the research and hypotheses. ?? ?? ?? ?? Page | 2 ...read more.

This student written piece of work is one of many that can be found in our GCSE Green Plants as Organisms section.