Biology Coursework Analysis and Evaluation (transpiration)

Essay by sweetness029High School, 11th gradeB-, February 2004

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Analysis -

After doing this experiment, I can see from my graph that a decrease in light intensity reduces the rate of transpiration. This is because when there is a high level of light intensity it starts to evaporate any water and because there was such intense light on the plant at the beginning of the experiment water quickly evaporated. This is also due to the fact that leaf water is also needed to aid in photosynthesis and to stop the leaves from wilting. Transpiration takes place more during the day than it does at night because light causes the stomata to open and when they are open water is lost faster. Water evaporates from the spongy cells in leaves into the air spaces. Next, the water vapour diffuses through the stomata into the air. The process of transpiration takes place to continuously draw water up the xylem from the roots.

This water is then drawn into the spongy cells to replace the lost water.

My results agreed with my hypothesis because transpiration did increase when the light intensity did. My graph further showed my prediction to be accurate.

Evaluation -

The method that I used proved to be quite accurate because it helped me to make a relevant conclusion about the factors affecting the rate of transpiration. My results were accurate enough to show that there was strong correlation between the possible factor (light intensity) and the rate of transpiration.

In my results there was only 1 anomalous result, which was at 40cm away from the light. This result could have come about by a mistake in placing the lamp. At some points in the experiment I noticed that the base of my lamp was on the point but the actual bulb was still much closer to...